[PATCH 0/3] line-log: integrate -L with the standard log output pipeline

[PATCH 0/3] line-log: integrate -L with the standard log output pipeline

[Michael Montalbo via GitGitGadget]

Since its introduction, git log -L has short-circuited from
log_tree_commit() into its own output function, bypassing log_tree_diff()
and log_tree_diff_flush(). This skips no_free save/restore,
always_show_header, diff_free() cleanup, and means that pickaxe (-S, -G,
--find-object) and --diff-filter cannot suppress commits whose pairs are all
filtered out, because show_log() runs before diffcore_std().

This series restructures the flow so that -L goes through the same
log_tree_diff() -> log_tree_diff_flush() path as normal single-parent and
merge diffs, then uses that to enable several non-patch diff formats.

Patch 1: revision: move -L setup before output_format-to-diff derivation

Preparatory reorder in setup_revisions(). The -L block sets a default
DIFF_FORMAT_PATCH when no format is requested; move it before the derivation
of revs->diff from output_format so the default is visible to that check. No
behavior change on its own.

Patch 2: line-log: integrate -L output with the standard log-tree pipeline

Rename line_log_print() to line_log_queue_pairs(), stripping it down to only
queue pre-computed filepairs. log_tree_diff_flush() handles show_log(),
diffcore_std(), and diff_flush(). This fixes pickaxe and --diff-filter
suppression, and aligns the commit/diff separator with the rest of log
output. Also rejects --full-diff, which is meaningless when filepairs are
pre-computed.

Patch 3: line-log: allow non-patch diff formats with -L

Expand the allowlist to accept --raw, --name-only, --name-status, and
--summary. These only read filepair metadata already set by the line-log
machinery. Diff stat formats (--stat, --numstat, --shortstat, --dirstat)
remain blocked because they call compute_diffstat() on full blob content and
would show whole-file statistics rather than range-scoped ones.

Michael Montalbo (3):
  revision: move -L setup before output_format-to-diff derivation
  line-log: integrate -L output with the standard log-tree pipeline
  line-log: allow non-patch diff formats with -L

 Documentation/line-range-options.adoc         | 10 +-
 line-log.c                                    | 30 ++----
 line-log.h                                    |  2 +-
 log-tree.c                                    |  9 +-
 revision.c                                    | 25 +++--
 t/t4211-line-log.sh                           | 99 ++++++++++++++++---
 t/t4211/sha1/expect.parallel-change-f-to-main |  1 -
 .../sha256/expect.parallel-change-f-to-main   |  1 -
 8 files changed, 120 insertions(+), 57 deletions(-)


base-commit: 9f223ef1c026d91c7ac68cc0211bde255dda6199
Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-2094%2Fmmontalbo%2Fmm%2Fline-log-use-log-tree-diff-flush-v1
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-2094/mmontalbo/mm/line-log-use-log-tree-diff-flush-v1
Pull-Request: https://github.com/gitgitgadget/git/pull/2094
-- 
gitgitgadget

[PATCH 1/3] revision: move -L setup before output_format-to-diff derivation

[Michael Montalbo via GitGitGadget]

From: Michael Montalbo <mmontalbo@gmail.com>

The line_level_traverse block sets a default DIFF_FORMAT_PATCH when
no output format has been explicitly requested.  This default must
be visible to the "Did the user ask for any diff output?" check
that derives revs->diff from revs->diffopt.output_format.

Currently the -L block runs after that derivation, so revs->diff
stays 0 when no explicit format is given.  This does not matter yet
because log_tree_commit() short-circuits into line_log_print()
before consulting revs->diff, but the next commit will route -L
through the normal log_tree_diff() path, which checks revs->diff.

Move the block above the derivation so the default DIFF_FORMAT_PATCH
is in place when revs->diff is computed.  No behavior change on its
own.

Signed-off-by: Michael Montalbo <mmontalbo@gmail.com>
---
 revision.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/revision.c b/revision.c
index 599b3a66c3..4a8e24bc38 100644
--- a/revision.c
+++ b/revision.c
@@ -3112,6 +3112,14 @@ int setup_revisions(int argc, const char **argv, struct rev_info *revs, struct s
 		object_context_release(&oc);
 	}
 
+	if (revs->line_level_traverse) {
+		if (want_ancestry(revs))
+			revs->limited = 1;
+		revs->topo_order = 1;
+		if (!revs->diffopt.output_format)
+			revs->diffopt.output_format = DIFF_FORMAT_PATCH;
+	}
+
 	/* Did the user ask for any diff output? Run the diff! */
 	if (revs->diffopt.output_format & ~DIFF_FORMAT_NO_OUTPUT)
 		revs->diff = 1;
@@ -3125,14 +3133,6 @@ int setup_revisions(int argc, const char **argv, struct rev_info *revs, struct s
 	if (revs->diffopt.objfind)
 		revs->simplify_history = 0;
 
-	if (revs->line_level_traverse) {
-		if (want_ancestry(revs))
-			revs->limited = 1;
-		revs->topo_order = 1;
-		if (!revs->diffopt.output_format)
-			revs->diffopt.output_format = DIFF_FORMAT_PATCH;
-	}
-
 	if (revs->topo_order && !generation_numbers_enabled(the_repository))
 		revs->limited = 1;
 
-- 
gitgitgadget

[PATCH 2/3] line-log: integrate -L output with the standard log-tree pipeline

[Michael Montalbo via GitGitGadget]

From: Michael Montalbo <mmontalbo@gmail.com>

`git log -L` has bypassed log_tree_diff() and log_tree_diff_flush()
since the feature was introduced, short-circuiting from
log_tree_commit() directly into line_log_print().  This skips the
no_free save/restore (noted in a NEEDSWORK comment added by
f8781bfda3), the always_show_header fallback, show_diff_of_diff(),
and diff_free() cleanup.

Restructure so that -L flows through log_tree_diff() ->
log_tree_diff_flush(), the same path used by the normal
single-parent and merge diff codepaths:

 - Rename line_log_print() to line_log_queue_pairs() and strip it
   down to just queuing pre-computed filepairs.  The show_log(),
   separator, diffcore_std(), and diff_flush() calls are removed
   since log_tree_diff_flush() handles all of those.

 - In log_tree_diff(), call line_log_queue_pairs() then
   log_tree_diff_flush(), mirroring the diff_tree_oid() + flush
   pattern used by the single-parent and merge codepaths.

 - Remove the early return in log_tree_commit() that bypassed
   no_free save/restore, always_show_header, and diff_free().

Because show_log() is now deferred until after diffcore_std() inside
log_tree_diff_flush(), pickaxe (-S, -G, --find-object) and
--diff-filter now properly suppress commits when all pairs are
filtered out.

The blank-line separator between commit header and diff changes
slightly: the old code printed one unconditionally, while
log_tree_diff_flush() only emits one for verbose headers.  This
matches the rest of log output.

Also reject --full-diff, which is meaningless with -L: the filepairs
are pre-computed during the history walk and scoped to tracked paths,
so there is no tree diff to widen.

Update tests accordingly.

Signed-off-by: Michael Montalbo <mmontalbo@gmail.com>
---
 line-log.c                                    | 30 ++++-------
 line-log.h                                    |  2 +-
 log-tree.c                                    |  9 ++--
 revision.c                                    |  2 +
 t/t4211-line-log.sh                           | 52 ++++++++++++++-----
 t/t4211/sha1/expect.parallel-change-f-to-main |  1 -
 .../sha256/expect.parallel-change-f-to-main   |  1 -
 7 files changed, 56 insertions(+), 41 deletions(-)

diff --git a/line-log.c b/line-log.c
index 858a899cd2..7ee55b05cc 100644
--- a/line-log.c
+++ b/line-log.c
@@ -13,7 +13,6 @@
 #include "revision.h"
 #include "xdiff-interface.h"
 #include "strbuf.h"
-#include "log-tree.h"
 #include "line-log.h"
 #include "setup.h"
 #include "strvec.h"
@@ -1004,29 +1003,18 @@ static int process_all_files(struct line_log_data **range_out,
 	return changed;
 }
 
-int line_log_print(struct rev_info *rev, struct commit *commit)
+void line_log_queue_pairs(struct rev_info *rev, struct commit *commit)
 {
-	show_log(rev);
-	if (!(rev->diffopt.output_format & DIFF_FORMAT_NO_OUTPUT)) {
-		struct line_log_data *range = lookup_line_range(rev, commit);
-		struct line_log_data *r;
-		const char *prefix = diff_line_prefix(&rev->diffopt);
-
-		fprintf(rev->diffopt.file, "%s\n", prefix);
-
-		for (r = range; r; r = r->next) {
-			if (r->pair) {
-				struct diff_filepair *p =
-					diff_filepair_dup(r->pair);
-				p->line_ranges = &r->ranges;
-				diff_q(&diff_queued_diff, p);
-			}
-		}
+	struct line_log_data *range = lookup_line_range(rev, commit);
+	struct line_log_data *r;
 
-		diffcore_std(&rev->diffopt);
-		diff_flush(&rev->diffopt);
+	for (r = range; r; r = r->next) {
+		if (r->pair) {
+			struct diff_filepair *p = diff_filepair_dup(r->pair);
+			p->line_ranges = &r->ranges;
+			diff_q(&diff_queued_diff, p);
+		}
 	}
-	return 1;
 }
 
 static int bloom_filter_check(struct rev_info *rev,
diff --git a/line-log.h b/line-log.h
index 04a6ea64d3..99e1755ce3 100644
--- a/line-log.h
+++ b/line-log.h
@@ -46,7 +46,7 @@ int line_log_filter(struct rev_info *rev);
 int line_log_process_ranges_arbitrary_commit(struct rev_info *rev,
 						    struct commit *commit);
 
-int line_log_print(struct rev_info *rev, struct commit *commit);
+void line_log_queue_pairs(struct rev_info *rev, struct commit *commit);
 
 void line_log_free(struct rev_info *rev);
 
diff --git a/log-tree.c b/log-tree.c
index 7e048701d0..1ead481891 100644
--- a/log-tree.c
+++ b/log-tree.c
@@ -1105,6 +1105,11 @@ static int log_tree_diff(struct rev_info *opt, struct commit *commit, struct log
 	if (!all_need_diff && !opt->merges_need_diff)
 		return 0;
 
+	if (opt->line_level_traverse) {
+		line_log_queue_pairs(opt, commit);
+		return log_tree_diff_flush(opt);
+	}
+
 	parse_commit_or_die(commit);
 	oid = get_commit_tree_oid(commit);
 
@@ -1179,10 +1184,6 @@ int log_tree_commit(struct rev_info *opt, struct commit *commit)
 	opt->loginfo = &log;
 	opt->diffopt.no_free = 1;
 
-	/* NEEDSWORK: no restoring of no_free?  Why? */
-	if (opt->line_level_traverse)
-		return line_log_print(opt, commit);
-
 	if (opt->track_linear && !opt->linear && !opt->reverse_output_stage)
 		fprintf(opt->diffopt.file, "\n%s\n", opt->break_bar);
 	shown = log_tree_diff(opt, commit, &log);
diff --git a/revision.c b/revision.c
index 4a8e24bc38..a1c795de96 100644
--- a/revision.c
+++ b/revision.c
@@ -3181,6 +3181,8 @@ int setup_revisions(int argc, const char **argv, struct rev_info *revs, struct s
 	if (revs->line_level_traverse &&
 	    (revs->diffopt.output_format & ~(DIFF_FORMAT_PATCH | DIFF_FORMAT_NO_OUTPUT)))
 		die(_("-L does not yet support diff formats besides -p and -s"));
+	if (revs->line_level_traverse && revs->full_diff)
+		die(_("-L is not compatible with --full-diff"));
 
 	if (revs->expand_tabs_in_log < 0)
 		revs->expand_tabs_in_log = revs->expand_tabs_in_log_default;
diff --git a/t/t4211-line-log.sh b/t/t4211-line-log.sh
index aaf197d2ed..1d566ea9bd 100755
--- a/t/t4211-line-log.sh
+++ b/t/t4211-line-log.sh
@@ -368,7 +368,6 @@ test_expect_success '-L diff output includes index and new file mode' '
 
 test_expect_success '-L with --word-diff' '
 	cat >expect <<-\EOF &&
-
 	diff --git a/file.c b/file.c
 	--- a/file.c
 	+++ b/file.c
@@ -377,7 +376,6 @@ test_expect_success '-L with --word-diff' '
 	{
 	    return [-F2;-]{+F2 + 2;+}
 	}
-
 	diff --git a/file.c b/file.c
 	new file mode 100644
 	--- /dev/null
@@ -433,7 +431,6 @@ test_expect_success 'show line-log with graph' '
 	null_blob=$(test_oid zero | cut -c1-7) &&
 	qz_to_tab_space >expect <<-EOF &&
 	* $head_oid Modify func2() in file.c
-	|Z
 	| diff --git a/file.c b/file.c
 	| index $head_blob_old..$head_blob_new 100644
 	| --- a/file.c
@@ -445,7 +442,6 @@ test_expect_success 'show line-log with graph' '
 	| +    return F2 + 2;
 	|  }
 	* $root_oid Add func1() and func2() in file.c
-	ZZ
 	  diff --git a/file.c b/file.c
 	  new file mode 100644
 	  index $null_blob..$root_blob
@@ -494,23 +490,17 @@ test_expect_success '-L --find-object does not crash with merge and rename' '
 		--find-object=$(git rev-parse HEAD:file) >actual
 '
 
-# Commit-level filtering with pickaxe does not yet work for -L.
-# show_log() prints the commit header before diffcore_std() runs
-# pickaxe, so commits cannot be suppressed even when no diff pairs
-# survive filtering.  Fixing this would require deferring show_log()
-# until after diffcore_std(), which is a larger restructuring of the
-# log-tree output pipeline.
-test_expect_failure '-L -G should filter commits by pattern' '
+test_expect_success '-L -G should filter commits by pattern' '
 	git log --format="%s" --no-patch -L 1,1:file -G "nomatch" >actual &&
 	test_must_be_empty actual
 '
 
-test_expect_failure '-L -S should filter commits by pattern' '
+test_expect_success '-L -S should filter commits by pattern' '
 	git log --format="%s" --no-patch -L 1,1:file -S "nomatch" >actual &&
 	test_must_be_empty actual
 '
 
-test_expect_failure '-L --find-object should filter commits by object' '
+test_expect_success '-L --find-object should filter commits by object' '
 	git log --format="%s" --no-patch -L 1,1:file \
 		--find-object=$ZERO_OID >actual &&
 	test_must_be_empty actual
@@ -711,4 +701,40 @@ test_expect_success '-L with -G filters to diff-text matches' '
 	grep "F2 + 2" actual
 '
 
+test_expect_success '-L with --diff-filter=M excludes root commit' '
+	git checkout parent-oids &&
+	git log -L:func2:file.c --diff-filter=M --format=%s --no-patch >actual &&
+	# Root commit is an Add (A), not a Modify (M), so it should
+	# be excluded; only the modification commit remains.
+	echo "Modify func2() in file.c" >expect &&
+	test_cmp expect actual
+'
+
+test_expect_success '-L with --diff-filter=A shows only root commit' '
+	git checkout parent-oids &&
+	git log -L:func2:file.c --diff-filter=A --format=%s --no-patch >actual &&
+	echo "Add func1() and func2() in file.c" >expect &&
+	test_cmp expect actual
+'
+
+test_expect_success '-L with -S suppresses non-matching commits' '
+	git checkout parent-oids &&
+	git log -L:func2:file.c -S "F2 + 2" --format=%s --no-patch >actual &&
+	# Only the commit that changes the count of "F2 + 2" should appear.
+	echo "Modify func2() in file.c" >expect &&
+	test_cmp expect actual
+'
+
+test_expect_success '--full-diff is not supported with -L' '
+	test_must_fail git log -L1,24:b.c --full-diff 2>err &&
+	test_grep "not compatible with --full-diff" err
+'
+
+test_expect_success '-L --oneline has no extra blank line before diff' '
+	git checkout parent-oids &&
+	git log --oneline -L:func2:file.c -1 >actual &&
+	# Oneline header on line 1, diff starts immediately on line 2
+	sed -n 2p actual | grep "^diff --git"
+'
+
 test_done
diff --git a/t/t4211/sha1/expect.parallel-change-f-to-main b/t/t4211/sha1/expect.parallel-change-f-to-main
index 65a8cc673a..6d7a201036 100644
--- a/t/t4211/sha1/expect.parallel-change-f-to-main
+++ b/t/t4211/sha1/expect.parallel-change-f-to-main
@@ -5,7 +5,6 @@ Date:   Fri Apr 12 16:16:24 2013 +0200
 
     Merge across the rename
 
-
 commit 6ce3c4ff690136099bb17e1a8766b75764726ea7
 Author: Thomas Rast <trast@student.ethz.ch>
 Date:   Thu Feb 28 10:49:50 2013 +0100
diff --git a/t/t4211/sha256/expect.parallel-change-f-to-main b/t/t4211/sha256/expect.parallel-change-f-to-main
index 3178989253..c93e03bef4 100644
--- a/t/t4211/sha256/expect.parallel-change-f-to-main
+++ b/t/t4211/sha256/expect.parallel-change-f-to-main
@@ -5,7 +5,6 @@ Date:   Fri Apr 12 16:16:24 2013 +0200
 
     Merge across the rename
 
-
 commit 4f7a58195a92c400e28a2354328587f1ff14fb77f5cf894536f17ccbc72931b9
 Author: Thomas Rast <trast@student.ethz.ch>
 Date:   Thu Feb 28 10:49:50 2013 +0100
-- 
gitgitgadget

[PATCH 3/3] line-log: allow non-patch diff formats with -L

[Michael Montalbo via GitGitGadget]

From: Michael Montalbo <mmontalbo@gmail.com>

Now that -L flows through log_tree_diff_flush() and diff_flush(),
metadata-only diff formats work because they only read filepair
fields (status, mode, path, oid) already set on the pre-computed
pairs.

Expand the allowlist in setup_revisions() to also accept --raw,
--name-only, --name-status, and --summary.  Diff stat formats
(--stat, --numstat, --shortstat, --dirstat) remain blocked because
they call compute_diffstat() on full blob content and would show
whole-file statistics rather than range-scoped ones.

Signed-off-by: Michael Montalbo <mmontalbo@gmail.com>
---
 Documentation/line-range-options.adoc | 10 +++---
 revision.c                            |  7 ++--
 t/t4211-line-log.sh                   | 47 +++++++++++++++++++++++++--
 3 files changed, 56 insertions(+), 8 deletions(-)

diff --git a/Documentation/line-range-options.adoc b/Documentation/line-range-options.adoc
index ecb2c79fb9..72f639b5e7 100644
--- a/Documentation/line-range-options.adoc
+++ b/Documentation/line-range-options.adoc
@@ -8,12 +8,14 @@
 	give zero or one positive revision arguments, and
 	_<start>_ and _<end>_ (or _<funcname>_) must exist in the starting revision.
 	You can specify this option more than once. Implies `--patch`.
-	Patch output can be suppressed using `--no-patch`, but other diff formats
-	(namely `--raw`, `--numstat`, `--shortstat`, `--dirstat`, `--summary`,
-	`--name-only`, `--name-status`, `--check`) are not currently implemented.
+	Patch output can be suppressed using `--no-patch`.
+	Non-patch diff formats `--raw`, `--name-only`, `--name-status`,
+	and `--summary` are supported.  Diff stat formats
+	(`--stat`, `--numstat`, `--shortstat`, `--dirstat`) are not
+	currently implemented.
 +
 Patch formatting options such as `--word-diff`, `--color-moved`,
 `--no-prefix`, and whitespace options (`-w`, `-b`) are supported,
-as are pickaxe options (`-S`, `-G`).
+as are pickaxe options (`-S`, `-G`) and `--diff-filter`.
 +
 include::line-range-format.adoc[]
diff --git a/revision.c b/revision.c
index a1c795de96..b41ec4016b 100644
--- a/revision.c
+++ b/revision.c
@@ -3179,8 +3179,11 @@ int setup_revisions(int argc, const char **argv, struct rev_info *revs, struct s
 		die(_("the option '%s' requires '%s'"), "--grep-reflog", "--walk-reflogs");
 
 	if (revs->line_level_traverse &&
-	    (revs->diffopt.output_format & ~(DIFF_FORMAT_PATCH | DIFF_FORMAT_NO_OUTPUT)))
-		die(_("-L does not yet support diff formats besides -p and -s"));
+	    (revs->diffopt.output_format &
+	     ~(DIFF_FORMAT_PATCH | DIFF_FORMAT_NO_OUTPUT |
+	       DIFF_FORMAT_RAW | DIFF_FORMAT_NAME |
+	       DIFF_FORMAT_NAME_STATUS | DIFF_FORMAT_SUMMARY)))
+		die(_("-L does not yet support the requested diff format"));
 	if (revs->line_level_traverse && revs->full_diff)
 		die(_("-L is not compatible with --full-diff"));
 
diff --git a/t/t4211-line-log.sh b/t/t4211-line-log.sh
index 1d566ea9bd..63cf8e5d9f 100755
--- a/t/t4211-line-log.sh
+++ b/t/t4211-line-log.sh
@@ -155,8 +155,45 @@ test_expect_success '-p shows the default patch output' '
 	test_cmp expect actual
 '
 
-test_expect_success '--raw is forbidden' '
-	test_must_fail git log -L1,24:b.c --raw
+test_expect_success '--raw shows mode, oid, status and path' '
+	git log -L1,24:b.c --raw --format= >actual &&
+	grep "^:100644 100644 [0-9a-f]\{7\} [0-9a-f]\{7\} M	b.c$" actual &&
+	! grep "^diff --git" actual &&
+	! grep "^@@" actual
+'
+
+test_expect_success '--name-only shows path' '
+	git log -L1,24:b.c --name-only --format= >actual &&
+	grep "^b.c$" actual &&
+	! grep "^diff --git" actual &&
+	! grep "^@@" actual
+'
+
+test_expect_success '--name-status shows status and path' '
+	git log -L1,24:b.c --name-status --format= >actual &&
+	grep "^M	b.c$" actual &&
+	! grep "^diff --git" actual &&
+	! grep "^@@" actual
+'
+
+test_expect_success '--stat is not yet supported with -L' '
+	test_must_fail git log -L1,24:b.c --stat 2>err &&
+	test_grep "does not yet support" err
+'
+
+test_expect_success '--numstat is not yet supported with -L' '
+	test_must_fail git log -L1,24:b.c --numstat 2>err &&
+	test_grep "does not yet support" err
+'
+
+test_expect_success '--shortstat is not yet supported with -L' '
+	test_must_fail git log -L1,24:b.c --shortstat 2>err &&
+	test_grep "does not yet support" err
+'
+
+test_expect_success '--dirstat is not yet supported with -L' '
+	test_must_fail git log -L1,24:b.c --dirstat 2>err &&
+	test_grep "does not yet support" err
 '
 
 test_expect_success 'setup for checking fancy rename following' '
@@ -737,4 +774,10 @@ test_expect_success '-L --oneline has no extra blank line before diff' '
 	sed -n 2p actual | grep "^diff --git"
 '
 
+test_expect_success '--summary shows new file on root commit' '
+	git checkout parent-oids &&
+	git log -L:func2:file.c --summary --format= >actual &&
+	grep "create mode 100644 file.c" actual
+'
+
 test_done
-- 
gitgitgadget

Re: [PATCH 0/3] line-log: integrate -L with the standard log output pipeline

[Junio C Hamano]

"Michael Montalbo via GitGitGadget" <gitgitgadget@gmail.com> writes:

> Since its introduction, git log -L has short-circuited from
> log_tree_commit() into its own output function, bypassing log_tree_diff()
> and log_tree_diff_flush(). This skips no_free save/restore,
> always_show_header, diff_free() cleanup, and means that pickaxe (-S, -G,
> --find-object) and --diff-filter cannot suppress commits whose pairs are all
> filtered out, because show_log() runs before diffcore_std().
>
> This series restructures the flow so that -L goes through the same
> log_tree_diff() -> log_tree_diff_flush() path as normal single-parent and
> merge diffs, then uses that to enable several non-patch diff formats.

This unfortunately saw no reviews and

  https://lore.kernel.org/git/pull.2094.git.1777349126.gitgitgadget@gmail.com/

does not show the previous rouns so I am assuming nobody is
interested in the topic?  

Or are people more busily writing their own patches than reviewing
others' patches?  Unfortunately that is not sustainable.




> Patch 1: revision: move -L setup before output_format-to-diff derivation
>
> Preparatory reorder in setup_revisions(). The -L block sets a default
> DIFF_FORMAT_PATCH when no format is requested; move it before the derivation
> of revs->diff from output_format so the default is visible to that check. No
> behavior change on its own.
>
> Patch 2: line-log: integrate -L output with the standard log-tree pipeline
>
> Rename line_log_print() to line_log_queue_pairs(), stripping it down to only
> queue pre-computed filepairs. log_tree_diff_flush() handles show_log(),
> diffcore_std(), and diff_flush(). This fixes pickaxe and --diff-filter
> suppression, and aligns the commit/diff separator with the rest of log
> output. Also rejects --full-diff, which is meaningless when filepairs are
> pre-computed.
>
> Patch 3: line-log: allow non-patch diff formats with -L
>
> Expand the allowlist to accept --raw, --name-only, --name-status, and
> --summary. These only read filepair metadata already set by the line-log
> machinery. Diff stat formats (--stat, --numstat, --shortstat, --dirstat)
> remain blocked because they call compute_diffstat() on full blob content and
> would show whole-file statistics rather than range-scoped ones.
>
> Michael Montalbo (3):
>   revision: move -L setup before output_format-to-diff derivation
>   line-log: integrate -L output with the standard log-tree pipeline
>   line-log: allow non-patch diff formats with -L
>
>  Documentation/line-range-options.adoc         | 10 +-
>  line-log.c                                    | 30 ++----
>  line-log.h                                    |  2 +-
>  log-tree.c                                    |  9 +-
>  revision.c                                    | 25 +++--
>  t/t4211-line-log.sh                           | 99 ++++++++++++++++---
>  t/t4211/sha1/expect.parallel-change-f-to-main |  1 -
>  .../sha256/expect.parallel-change-f-to-main   |  1 -
>  8 files changed, 120 insertions(+), 57 deletions(-)
>
>
> base-commit: 9f223ef1c026d91c7ac68cc0211bde255dda6199
> Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-2094%2Fmmontalbo%2Fmm%2Fline-log-use-log-tree-diff-flush-v1
> Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-2094/mmontalbo/mm/line-log-use-log-tree-diff-flush-v1
> Pull-Request: https://github.com/gitgitgadget/git/pull/2094

Re: [PATCH 0/3] line-log: integrate -L with the standard log output pipeline

[D. Ben Knoble]

Hi Michael,

On Tue, Apr 28, 2026 at 12:06 AM Michael Montalbo via GitGitGadget
<gitgitgadget@gmail.com> wrote:
>
> Since its introduction, git log -L has short-circuited from
> log_tree_commit() into its own output function, bypassing log_tree_diff()
> and log_tree_diff_flush(). This skips no_free save/restore,
> always_show_header, diff_free() cleanup, and means that pickaxe (-S, -G,
> --find-object) and --diff-filter cannot suppress commits whose pairs are all
> filtered out, because show_log() runs before diffcore_std().
>
> This series restructures the flow so that -L goes through the same
> log_tree_diff() -> log_tree_diff_flush() path as normal single-parent and
> merge diffs, then uses that to enable several non-patch diff formats.

Cleanup by itself to shrink the number of concepts in the code is
already a good thing IMO, so getting additional features out of it is
even nicer.

> Patch 1: revision: move -L setup before output_format-to-diff derivation
>
> Preparatory reorder in setup_revisions(). The -L block sets a default
> DIFF_FORMAT_PATCH when no format is requested; move it before the derivation
> of revs->diff from output_format so the default is visible to that check. No
> behavior change on its own.

Straightforward, nice.

>
> Patch 2: line-log: integrate -L output with the standard log-tree pipeline
>
> Rename line_log_print() to line_log_queue_pairs(), stripping it down to only
> queue pre-computed filepairs. log_tree_diff_flush() handles show_log(),
> diffcore_std(), and diff_flush(). This fixes pickaxe and --diff-filter
> suppression, and aligns the commit/diff separator with the rest of log
> output. Also rejects --full-diff, which is meaningless when filepairs are
> pre-computed.

At first I questioned the removal of the DIFF_FORMAT_NO_OUTPUT
conditional in line_log_queue_pairs, but now that it only queues pairs
it shouldn't be checking output formats. Good.

I also noted that log_tree_diff() returns the result of
log_tree_diff_flush() in the -L case, which is a bit different from
the other patterns. I think the difference is that the other cases
have some conditional logic around the log_tree_diff_flush cases (?)
but I'm not sure. Perhaps that branch should also be looking at
opt->loginfo ?

Finally, I wonder if in describing the removal of the early return:

> - Remove the early return in log_tree_commit() that bypassed
>   no_free save/restore, always_show_header, and diff_free().

we might want to be more explicit that this is _because_ line-level
diff is now handled in the regular pipeline?

[I suppose we could, in theory, split the rejection of --full-diff to
a separate prep commit, idk.j]

> Patch 3: line-log: allow non-patch diff formats with -L
>
> Expand the allowlist to accept --raw, --name-only, --name-status, and
> --summary. These only read filepair metadata already set by the line-log
> machinery. Diff stat formats (--stat, --numstat, --shortstat, --dirstat)
> remain blocked because they call compute_diffstat() on full blob content and
> would show whole-file statistics rather than range-scoped ones.

Short and sweet.

The stat formats are kind of like --full-diff, and I think they should
probably all be rejected or all allowed: since the stats are based on
the full-diff, it makes sense to enable them if we can also make -L +
--full-diff semantically sensible.

Otherwise, we'd need to find a way to make the stat formats scoped for -L.

> Michael Montalbo (3):
>   revision: move -L setup before output_format-to-diff derivation
>   line-log: integrate -L output with the standard log-tree pipeline
>   line-log: allow non-patch diff formats with -L
>
>  Documentation/line-range-options.adoc         | 10 +-
>  line-log.c                                    | 30 ++----
>  line-log.h                                    |  2 +-
>  log-tree.c                                    |  9 +-
>  revision.c                                    | 25 +++--
>  t/t4211-line-log.sh                           | 99 ++++++++++++++++---
>  t/t4211/sha1/expect.parallel-change-f-to-main |  1 -
>  .../sha256/expect.parallel-change-f-to-main   |  1 -
>  8 files changed, 120 insertions(+), 57 deletions(-)
>
>
> base-commit: 9f223ef1c026d91c7ac68cc0211bde255dda6199
> Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-2094%2Fmmontalbo%2Fmm%2Fline-log-use-log-tree-diff-flush-v1
> Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-2094/mmontalbo/mm/line-log-use-log-tree-diff-flush-v1
> Pull-Request: https://github.com/gitgitgadget/git/pull/2094
> --
> gitgitgadget

A few other comments:

- Tests should use test_grep; some do, but some don't.
- There is one occurrence of "sed | grep" that I wonder if we want to
rewrite to avoid issues with exit status one side of the pipe?

Thanks for working on this!

[Apologies for the unusual review format; this was easier for me at
the moment than digging up the individual patches, and I don't think
_most_ of the review would benefit from spreading out across multiple
mails.]

-- 
D. Ben Knoble

Re: [PATCH 0/3] line-log: integrate -L with the standard log output pipeline

[Michael Montalbo]

On Fri, May 22, 2026 at 11:46 AM D. Ben Knoble <ben.knoble@gmail.com> wrote:
>
> Hi Michael,
>

Hi Ben,

Thanks for the thorough review!

> On Tue, Apr 28, 2026 at 12:06 AM Michael Montalbo via GitGitGadget <gitgitgadget@gmail.com> wrote:
>>
>> Since its introduction, git log -L has short-circuited from
>> log_tree_commit() into its own output function, bypassing log_tree_diff()
>> and log_tree_diff_flush(). This skips no_free save/restore,
>> always_show_header, diff_free() cleanup, and means that pickaxe (-S, -G,
>> --find-object) and --diff-filter cannot suppress commits whose pairs are all
>> filtered out, because show_log() runs before diffcore_std().
>>
>> This series restructures the flow so that -L goes through the same
>> log_tree_diff() -> log_tree_diff_flush() path as normal single-parent and
>> merge diffs, then uses that to enable several non-patch diff formats.
>
>
> Cleanup by itself to shrink the number of concepts in the code is already a good thing IMO, so getting additional features out of it is even nicer.
>
>> Patch 1: revision: move -L setup before output_format-to-diff derivation
>>
>> Preparatory reorder in setup_revisions(). The -L block sets a default
>> DIFF_FORMAT_PATCH when no format is requested; move it before the derivation
>> of revs->diff from output_format so the default is visible to that check. No
>> behavior change on its own.
>
>
> Straightforward, nice.
>
>>
>> Patch 2: line-log: integrate -L output with the standard log-tree pipeline
>>
>> Rename line_log_print() to line_log_queue_pairs(), stripping it down to only
>> queue pre-computed filepairs. log_tree_diff_flush() handles show_log(),
>> diffcore_std(), and diff_flush(). This fixes pickaxe and --diff-filter
>> suppression, and aligns the commit/diff separator with the rest of log
>> output. Also rejects --full-diff, which is meaningless when filepairs are
>> pre-computed.
>
>
> At first I questioned the removal of the DIFF_FORMAT_NO_OUTPUT conditional in line_log_queue_pairs, but now that it only queues pairs it shouldn't be checking output formats. Good.
>
> I also noted that log_tree_diff() returns the result of log_tree_diff_flush() in the -L case, which is a bit different from the other patterns. I think the difference is that the other cases have some conditional logic around the log_tree_diff_flush cases (?) but I'm not sure. Perhaps that branch should also be looking at opt->loginfo ?
>

Good catch. In practice I think they agree, since `log_tree_diff_flush()`
returns 1 exactly when it calls `show_log()` which consumes loginfo,
but matching the existing convention is cleaner. Will update.

> Finally, I wonder if in describing the removal of the early return:
>
> > - Remove the early return in log_tree_commit() that bypassed
> >   no_free save/restore, always_show_header, and diff_free().
>
> we might want to be more explicit that this is _because_ line-level diff is now handled in the regular pipeline?
>

Agreed, will reword to: "Remove the early return in log_tree_commit()
that is no longer needed now that -L output flows through
log_tree_diff() and log_tree_diff_flush(); this restores no_free
save/restore, always_show_header, and diff_free() cleanup."

> [I suppose we could, in theory, split the rejection of --full-diff to a separate prep commit, idk.j]
>

It felt natural to me to put alongside the integration since
--full-diff is not yet implementable with pre-computed filepairs.
Happy to split it out if you feel strongly though.

>> Patch 3: line-log: allow non-patch diff formats with -L
>>
>> Expand the allowlist to accept --raw, --name-only, --name-status, and
>> --summary. These only read filepair metadata already set by the line-log
>> machinery. Diff stat formats (--stat, --numstat, --shortstat, --dirstat)
>> remain blocked because they call compute_diffstat() on full blob content and
>> would show whole-file statistics rather than range-scoped ones.
>
>
> Short and sweet.
>
> The stat formats are kind of like --full-diff, and I think they should probably all be rejected or all allowed: since the stats are based on the full-diff, it makes sense to enable them if we can also make -L + --full-diff semantically sensible.
>
> Otherwise, we'd need to find a way to make the stat formats scoped for -L.
>

I am working on a follow up series that takes the second path
you suggest: it adds a line-range filter in `diffcore_std()` that
clips insertions and deletions to the tracked ranges before
`compute_diffstat()` runs, so `--stat`, `--numstat`, etc. report
range-scoped numbers. That series builds on top of these three patches,
which is why stats remain blocked here.

For `--full-diff`, thinking about it more, the semantics would actually
be well-defined: "filter commits by line range, but show the full
diff for those commits." Right now, there might be a higher
implementation barrier, though. The line-log machinery fuses
commit filtering with diff generation, so there is no separate
"full diff" to fall back to for display. I will soften the rejection to
"not yet supported" rather than "incompatible," since it could
be wired up if someone separates the two concerns.

>>
>>
>> Michael Montalbo (3):
>>   revision: move -L setup before output_format-to-diff derivation
>>   line-log: integrate -L output with the standard log-tree pipeline
>>   line-log: allow non-patch diff formats with -L
>>
>>  Documentation/line-range-options.adoc         | 10 +-
>>  line-log.c                                    | 30 ++----
>>  line-log.h                                    |  2 +-
>>  log-tree.c                                    |  9 +-
>>  revision.c                                    | 25 +++--
>>  t/t4211-line-log.sh                           | 99 ++++++++++++++++---
>>  t/t4211/sha1/expect.parallel-change-f-to-main |  1 -
>>  .../sha256/expect.parallel-change-f-to-main   |  1 -
>>  8 files changed, 120 insertions(+), 57 deletions(-)
>>
>>
>> base-commit: 9f223ef1c026d91c7ac68cc0211bde255dda6199
>> Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-2094%2Fmmontalbo%2Fmm%2Fline-log-use-log-tree-diff-flush-v1
>> Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-2094/mmontalbo/mm/line-log-use-log-tree-diff-flush-v1
>> Pull-Request: https://github.com/gitgitgadget/git/pull/2094
>> --
>> gitgitgadget
>
>
> A few other comments:
>
> - Tests should use test_grep; some do, but some don't.
> - There is one occurrence of "sed | grep" that I wonder if we want to rewrite to avoid issues with exit status one side of the pipe?
>

Will fix both these issues.

> Thanks for working on this!
>
> [Apologies for the unusual review format; this was easier for me at the moment than digging up the individual patches, and I don't think _most_ of the review would benefit from spreading out across multiple mails.]
>

Thank you too! This review format worked fine for me :)

> --
> D. Ben Knoble

[PATCH v2 0/3] line-log: integrate -L with the standard log output pipeline

[Michael Montalbo via GitGitGadget]

Since its introduction, git log -L has short-circuited from
log_tree_commit() into its own output function, bypassing log_tree_diff()
and log_tree_diff_flush(). This skips no_free save/restore,
always_show_header, diff_free() cleanup, and means that pickaxe (-S, -G,
--find-object) and --diff-filter cannot suppress commits whose pairs are all
filtered out, because show_log() runs before diffcore_std().

This series restructures the flow so that -L goes through the same
log_tree_diff() -> log_tree_diff_flush() path as normal single-parent and
merge diffs, then uses that to enable several non-patch diff formats.

Patch 1: revision: move -L setup before output_format-to-diff derivation

Preparatory reorder in setup_revisions(). The -L block sets a default
DIFF_FORMAT_PATCH when no format is requested; move it before the derivation
of revs->diff from output_format so the default is visible to that check. No
behavior change on its own.

Patch 2: line-log: integrate -L output with the standard log-tree pipeline

Rename line_log_print() to line_log_queue_pairs(), stripping it down to only
queue pre-computed filepairs. log_tree_diff_flush() handles show_log(),
diffcore_std(), and diff_flush(). This fixes pickaxe and --diff-filter
suppression, and aligns the commit/diff separator with the rest of log
output. Rejects --full-diff, which is not yet supported when filepairs are
pre-computed.

Patch 3: line-log: allow non-patch diff formats with -L

Expand the allowlist to accept --raw, --name-only, --name-status, and
--summary. These only read filepair metadata already set by the line-log
machinery. Diff stat formats (--stat, --numstat, --shortstat, --dirstat)
remain blocked because they call compute_diffstat() on full blob content and
would show whole-file statistics rather than range-scoped ones.

Changes since v1:

 * Patch 2: use !opt->loginfo return convention in log_tree_diff() to match
   the existing single-parent and merge codepaths, instead of returning
   log_tree_diff_flush() directly.
 * Patch 2: reword the early-return removal to explicitly tie it to the
   pipeline change.
 * Patch 2: soften --full-diff rejection to "not yet supported".
 * Patches 2-3: use test_grep consistently in new tests.
 * Patch 2: replace sed | grep pipe with sed > file && test_grep for proper
   exit status handling.

Michael Montalbo (3):
  revision: move -L setup before output_format-to-diff derivation
  line-log: integrate -L output with the standard log-tree pipeline
  line-log: allow non-patch diff formats with -L

 Documentation/line-range-options.adoc         |  10 +-
 line-log.c                                    |  30 ++----
 line-log.h                                    |   2 +-
 log-tree.c                                    |  10 +-
 revision.c                                    |  24 +++--
 t/t4211-line-log.sh                           | 100 +++++++++++++++---
 t/t4211/sha1/expect.parallel-change-f-to-main |   1 -
 .../sha256/expect.parallel-change-f-to-main   |   1 -
 8 files changed, 121 insertions(+), 57 deletions(-)


base-commit: 9f223ef1c026d91c7ac68cc0211bde255dda6199
Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-2094%2Fmmontalbo%2Fmm%2Fline-log-use-log-tree-diff-flush-v2
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-2094/mmontalbo/mm/line-log-use-log-tree-diff-flush-v2
Pull-Request: https://github.com/gitgitgadget/git/pull/2094

Range-diff vs v1:

 1:  9633eb62c6 = 1:  9633eb62c6 revision: move -L setup before output_format-to-diff derivation
 2:  2d9e0ca015 ! 2:  7acfc5376e line-log: integrate -L output with the standard log-tree pipeline
     @@ Commit message
             log_tree_diff_flush(), mirroring the diff_tree_oid() + flush
             pattern used by the single-parent and merge codepaths.
      
     -     - Remove the early return in log_tree_commit() that bypassed
     -       no_free save/restore, always_show_header, and diff_free().
     +     - Remove the early return in log_tree_commit() that is no longer
     +       needed now that -L output flows through log_tree_diff() and
     +       log_tree_diff_flush(); this restores no_free save/restore,
     +       always_show_header, and diff_free() cleanup.
      
          Because show_log() is now deferred until after diffcore_std() inside
          log_tree_diff_flush(), pickaxe (-S, -G, --find-object) and
     @@ Commit message
          log_tree_diff_flush() only emits one for verbose headers.  This
          matches the rest of log output.
      
     -    Also reject --full-diff, which is meaningless with -L: the filepairs
     -    are pre-computed during the history walk and scoped to tracked paths,
     -    so there is no tree diff to widen.
     +    Also reject --full-diff, which is not yet supported with -L: the
     +    filepairs are pre-computed during the history walk and scoped to
     +    tracked line ranges, so there is currently no full-tree diff to
     +    fall back to for display.
      
          Update tests accordingly.
      
     @@ log-tree.c: static int log_tree_diff(struct rev_info *opt, struct commit *commit
       
      +	if (opt->line_level_traverse) {
      +		line_log_queue_pairs(opt, commit);
     -+		return log_tree_diff_flush(opt);
     ++		log_tree_diff_flush(opt);
     ++		return !opt->loginfo;
      +	}
      +
       	parse_commit_or_die(commit);
     @@ log-tree.c: int log_tree_commit(struct rev_info *opt, struct commit *commit)
      
       ## revision.c ##
      @@ revision.c: int setup_revisions(int argc, const char **argv, struct rev_info *revs, struct s
     + 		die(_("the option '%s' requires '%s'"), "--grep-reflog", "--walk-reflogs");
     + 
       	if (revs->line_level_traverse &&
     - 	    (revs->diffopt.output_format & ~(DIFF_FORMAT_PATCH | DIFF_FORMAT_NO_OUTPUT)))
     - 		die(_("-L does not yet support diff formats besides -p and -s"));
     -+	if (revs->line_level_traverse && revs->full_diff)
     -+		die(_("-L is not compatible with --full-diff"));
     +-	    (revs->diffopt.output_format & ~(DIFF_FORMAT_PATCH | DIFF_FORMAT_NO_OUTPUT)))
     +-		die(_("-L does not yet support diff formats besides -p and -s"));
     ++	    (revs->full_diff ||
     ++	     (revs->diffopt.output_format &
     ++	      ~(DIFF_FORMAT_PATCH | DIFF_FORMAT_NO_OUTPUT))))
     ++		die(_("-L does not yet support the requested diff format"));
       
       	if (revs->expand_tabs_in_log < 0)
       		revs->expand_tabs_in_log = revs->expand_tabs_in_log_default;
     @@ t/t4211-line-log.sh: test_expect_success '-L with -G filters to diff-text matche
      +	test_cmp expect actual
      +'
      +
     -+test_expect_success '--full-diff is not supported with -L' '
     ++test_expect_success '--full-diff is not yet supported with -L' '
      +	test_must_fail git log -L1,24:b.c --full-diff 2>err &&
     -+	test_grep "not compatible with --full-diff" err
     ++	test_grep "does not yet support" err
      +'
      +
      +test_expect_success '-L --oneline has no extra blank line before diff' '
      +	git checkout parent-oids &&
      +	git log --oneline -L:func2:file.c -1 >actual &&
      +	# Oneline header on line 1, diff starts immediately on line 2
     -+	sed -n 2p actual | grep "^diff --git"
     ++	sed -n 2p actual >line2 &&
     ++	test_grep "^diff --git" line2
      +'
      +
       test_done
 3:  06c24b416f ! 3:  10a3d8dde2 line-log: allow non-patch diff formats with -L
     @@ Documentation/line-range-options.adoc
      
       ## revision.c ##
      @@ revision.c: int setup_revisions(int argc, const char **argv, struct rev_info *revs, struct s
     - 		die(_("the option '%s' requires '%s'"), "--grep-reflog", "--walk-reflogs");
     - 
       	if (revs->line_level_traverse &&
     --	    (revs->diffopt.output_format & ~(DIFF_FORMAT_PATCH | DIFF_FORMAT_NO_OUTPUT)))
     --		die(_("-L does not yet support diff formats besides -p and -s"));
     -+	    (revs->diffopt.output_format &
     -+	     ~(DIFF_FORMAT_PATCH | DIFF_FORMAT_NO_OUTPUT |
     -+	       DIFF_FORMAT_RAW | DIFF_FORMAT_NAME |
     -+	       DIFF_FORMAT_NAME_STATUS | DIFF_FORMAT_SUMMARY)))
     -+		die(_("-L does not yet support the requested diff format"));
     - 	if (revs->line_level_traverse && revs->full_diff)
     - 		die(_("-L is not compatible with --full-diff"));
     + 	    (revs->full_diff ||
     + 	     (revs->diffopt.output_format &
     +-	      ~(DIFF_FORMAT_PATCH | DIFF_FORMAT_NO_OUTPUT))))
     ++	      ~(DIFF_FORMAT_PATCH | DIFF_FORMAT_NO_OUTPUT |
     ++		DIFF_FORMAT_RAW | DIFF_FORMAT_NAME |
     ++		DIFF_FORMAT_NAME_STATUS | DIFF_FORMAT_SUMMARY))))
     + 		die(_("-L does not yet support the requested diff format"));
       
     + 	if (revs->expand_tabs_in_log < 0)
      
       ## t/t4211-line-log.sh ##
      @@ t/t4211-line-log.sh: test_expect_success '-p shows the default patch output' '
     @@ t/t4211-line-log.sh: test_expect_success '-p shows the default patch output' '
      -	test_must_fail git log -L1,24:b.c --raw
      +test_expect_success '--raw shows mode, oid, status and path' '
      +	git log -L1,24:b.c --raw --format= >actual &&
     -+	grep "^:100644 100644 [0-9a-f]\{7\} [0-9a-f]\{7\} M	b.c$" actual &&
     -+	! grep "^diff --git" actual &&
     -+	! grep "^@@" actual
     ++	test_grep "^:100644 100644 [0-9a-f]\{7\} [0-9a-f]\{7\} M	b.c$" actual &&
     ++	! test_grep "^diff --git" actual &&
     ++	! test_grep "^@@" actual
      +'
      +
      +test_expect_success '--name-only shows path' '
      +	git log -L1,24:b.c --name-only --format= >actual &&
     -+	grep "^b.c$" actual &&
     -+	! grep "^diff --git" actual &&
     -+	! grep "^@@" actual
     ++	test_grep "^b.c$" actual &&
     ++	! test_grep "^diff --git" actual &&
     ++	! test_grep "^@@" actual
      +'
      +
      +test_expect_success '--name-status shows status and path' '
      +	git log -L1,24:b.c --name-status --format= >actual &&
     -+	grep "^M	b.c$" actual &&
     -+	! grep "^diff --git" actual &&
     -+	! grep "^@@" actual
     ++	test_grep "^M	b.c$" actual &&
     ++	! test_grep "^diff --git" actual &&
     ++	! test_grep "^@@" actual
      +'
      +
      +test_expect_success '--stat is not yet supported with -L' '
     @@ t/t4211-line-log.sh: test_expect_success '-p shows the default patch output' '
       
       test_expect_success 'setup for checking fancy rename following' '
      @@ t/t4211-line-log.sh: test_expect_success '-L --oneline has no extra blank line before diff' '
     - 	sed -n 2p actual | grep "^diff --git"
     + 	test_grep "^diff --git" line2
       '
       
      +test_expect_success '--summary shows new file on root commit' '
      +	git checkout parent-oids &&
      +	git log -L:func2:file.c --summary --format= >actual &&
     -+	grep "create mode 100644 file.c" actual
     ++	test_grep "create mode 100644 file.c" actual
      +'
      +
       test_done

-- 
gitgitgadget

[PATCH v2 1/3] revision: move -L setup before output_format-to-diff derivation

[Michael Montalbo via GitGitGadget]

From: Michael Montalbo <mmontalbo@gmail.com>

The line_level_traverse block sets a default DIFF_FORMAT_PATCH when
no output format has been explicitly requested.  This default must
be visible to the "Did the user ask for any diff output?" check
that derives revs->diff from revs->diffopt.output_format.

Currently the -L block runs after that derivation, so revs->diff
stays 0 when no explicit format is given.  This does not matter yet
because log_tree_commit() short-circuits into line_log_print()
before consulting revs->diff, but the next commit will route -L
through the normal log_tree_diff() path, which checks revs->diff.

Move the block above the derivation so the default DIFF_FORMAT_PATCH
is in place when revs->diff is computed.  No behavior change on its
own.

Signed-off-by: Michael Montalbo <mmontalbo@gmail.com>
---
 revision.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/revision.c b/revision.c
index 599b3a66c3..4a8e24bc38 100644
--- a/revision.c
+++ b/revision.c
@@ -3112,6 +3112,14 @@ int setup_revisions(int argc, const char **argv, struct rev_info *revs, struct s
 		object_context_release(&oc);
 	}
 
+	if (revs->line_level_traverse) {
+		if (want_ancestry(revs))
+			revs->limited = 1;
+		revs->topo_order = 1;
+		if (!revs->diffopt.output_format)
+			revs->diffopt.output_format = DIFF_FORMAT_PATCH;
+	}
+
 	/* Did the user ask for any diff output? Run the diff! */
 	if (revs->diffopt.output_format & ~DIFF_FORMAT_NO_OUTPUT)
 		revs->diff = 1;
@@ -3125,14 +3133,6 @@ int setup_revisions(int argc, const char **argv, struct rev_info *revs, struct s
 	if (revs->diffopt.objfind)
 		revs->simplify_history = 0;
 
-	if (revs->line_level_traverse) {
-		if (want_ancestry(revs))
-			revs->limited = 1;
-		revs->topo_order = 1;
-		if (!revs->diffopt.output_format)
-			revs->diffopt.output_format = DIFF_FORMAT_PATCH;
-	}
-
 	if (revs->topo_order && !generation_numbers_enabled(the_repository))
 		revs->limited = 1;
 
-- 
gitgitgadget

[PATCH v2 2/3] line-log: integrate -L output with the standard log-tree pipeline

[Michael Montalbo via GitGitGadget]

From: Michael Montalbo <mmontalbo@gmail.com>

`git log -L` has bypassed log_tree_diff() and log_tree_diff_flush()
since the feature was introduced, short-circuiting from
log_tree_commit() directly into line_log_print().  This skips the
no_free save/restore (noted in a NEEDSWORK comment added by
f8781bfda3), the always_show_header fallback, show_diff_of_diff(),
and diff_free() cleanup.

Restructure so that -L flows through log_tree_diff() ->
log_tree_diff_flush(), the same path used by the normal
single-parent and merge diff codepaths:

 - Rename line_log_print() to line_log_queue_pairs() and strip it
   down to just queuing pre-computed filepairs.  The show_log(),
   separator, diffcore_std(), and diff_flush() calls are removed
   since log_tree_diff_flush() handles all of those.

 - In log_tree_diff(), call line_log_queue_pairs() then
   log_tree_diff_flush(), mirroring the diff_tree_oid() + flush
   pattern used by the single-parent and merge codepaths.

 - Remove the early return in log_tree_commit() that is no longer
   needed now that -L output flows through log_tree_diff() and
   log_tree_diff_flush(); this restores no_free save/restore,
   always_show_header, and diff_free() cleanup.

Because show_log() is now deferred until after diffcore_std() inside
log_tree_diff_flush(), pickaxe (-S, -G, --find-object) and
--diff-filter now properly suppress commits when all pairs are
filtered out.

The blank-line separator between commit header and diff changes
slightly: the old code printed one unconditionally, while
log_tree_diff_flush() only emits one for verbose headers.  This
matches the rest of log output.

Also reject --full-diff, which is not yet supported with -L: the
filepairs are pre-computed during the history walk and scoped to
tracked line ranges, so there is currently no full-tree diff to
fall back to for display.

Update tests accordingly.

Signed-off-by: Michael Montalbo <mmontalbo@gmail.com>
---
 line-log.c                                    | 30 ++++-------
 line-log.h                                    |  2 +-
 log-tree.c                                    | 10 ++--
 revision.c                                    |  6 ++-
 t/t4211-line-log.sh                           | 53 ++++++++++++++-----
 t/t4211/sha1/expect.parallel-change-f-to-main |  1 -
 .../sha256/expect.parallel-change-f-to-main   |  1 -
 7 files changed, 60 insertions(+), 43 deletions(-)

diff --git a/line-log.c b/line-log.c
index 858a899cd2..7ee55b05cc 100644
--- a/line-log.c
+++ b/line-log.c
@@ -13,7 +13,6 @@
 #include "revision.h"
 #include "xdiff-interface.h"
 #include "strbuf.h"
-#include "log-tree.h"
 #include "line-log.h"
 #include "setup.h"
 #include "strvec.h"
@@ -1004,29 +1003,18 @@ static int process_all_files(struct line_log_data **range_out,
 	return changed;
 }
 
-int line_log_print(struct rev_info *rev, struct commit *commit)
+void line_log_queue_pairs(struct rev_info *rev, struct commit *commit)
 {
-	show_log(rev);
-	if (!(rev->diffopt.output_format & DIFF_FORMAT_NO_OUTPUT)) {
-		struct line_log_data *range = lookup_line_range(rev, commit);
-		struct line_log_data *r;
-		const char *prefix = diff_line_prefix(&rev->diffopt);
-
-		fprintf(rev->diffopt.file, "%s\n", prefix);
-
-		for (r = range; r; r = r->next) {
-			if (r->pair) {
-				struct diff_filepair *p =
-					diff_filepair_dup(r->pair);
-				p->line_ranges = &r->ranges;
-				diff_q(&diff_queued_diff, p);
-			}
-		}
+	struct line_log_data *range = lookup_line_range(rev, commit);
+	struct line_log_data *r;
 
-		diffcore_std(&rev->diffopt);
-		diff_flush(&rev->diffopt);
+	for (r = range; r; r = r->next) {
+		if (r->pair) {
+			struct diff_filepair *p = diff_filepair_dup(r->pair);
+			p->line_ranges = &r->ranges;
+			diff_q(&diff_queued_diff, p);
+		}
 	}
-	return 1;
 }
 
 static int bloom_filter_check(struct rev_info *rev,
diff --git a/line-log.h b/line-log.h
index 04a6ea64d3..99e1755ce3 100644
--- a/line-log.h
+++ b/line-log.h
@@ -46,7 +46,7 @@ int line_log_filter(struct rev_info *rev);
 int line_log_process_ranges_arbitrary_commit(struct rev_info *rev,
 						    struct commit *commit);
 
-int line_log_print(struct rev_info *rev, struct commit *commit);
+void line_log_queue_pairs(struct rev_info *rev, struct commit *commit);
 
 void line_log_free(struct rev_info *rev);
 
diff --git a/log-tree.c b/log-tree.c
index 7e048701d0..88b3019293 100644
--- a/log-tree.c
+++ b/log-tree.c
@@ -1105,6 +1105,12 @@ static int log_tree_diff(struct rev_info *opt, struct commit *commit, struct log
 	if (!all_need_diff && !opt->merges_need_diff)
 		return 0;
 
+	if (opt->line_level_traverse) {
+		line_log_queue_pairs(opt, commit);
+		log_tree_diff_flush(opt);
+		return !opt->loginfo;
+	}
+
 	parse_commit_or_die(commit);
 	oid = get_commit_tree_oid(commit);
 
@@ -1179,10 +1185,6 @@ int log_tree_commit(struct rev_info *opt, struct commit *commit)
 	opt->loginfo = &log;
 	opt->diffopt.no_free = 1;
 
-	/* NEEDSWORK: no restoring of no_free?  Why? */
-	if (opt->line_level_traverse)
-		return line_log_print(opt, commit);
-
 	if (opt->track_linear && !opt->linear && !opt->reverse_output_stage)
 		fprintf(opt->diffopt.file, "\n%s\n", opt->break_bar);
 	shown = log_tree_diff(opt, commit, &log);
diff --git a/revision.c b/revision.c
index 4a8e24bc38..c903f7a1b4 100644
--- a/revision.c
+++ b/revision.c
@@ -3179,8 +3179,10 @@ int setup_revisions(int argc, const char **argv, struct rev_info *revs, struct s
 		die(_("the option '%s' requires '%s'"), "--grep-reflog", "--walk-reflogs");
 
 	if (revs->line_level_traverse &&
-	    (revs->diffopt.output_format & ~(DIFF_FORMAT_PATCH | DIFF_FORMAT_NO_OUTPUT)))
-		die(_("-L does not yet support diff formats besides -p and -s"));
+	    (revs->full_diff ||
+	     (revs->diffopt.output_format &
+	      ~(DIFF_FORMAT_PATCH | DIFF_FORMAT_NO_OUTPUT))))
+		die(_("-L does not yet support the requested diff format"));
 
 	if (revs->expand_tabs_in_log < 0)
 		revs->expand_tabs_in_log = revs->expand_tabs_in_log_default;
diff --git a/t/t4211-line-log.sh b/t/t4211-line-log.sh
index aaf197d2ed..e3937138a9 100755
--- a/t/t4211-line-log.sh
+++ b/t/t4211-line-log.sh
@@ -368,7 +368,6 @@ test_expect_success '-L diff output includes index and new file mode' '
 
 test_expect_success '-L with --word-diff' '
 	cat >expect <<-\EOF &&
-
 	diff --git a/file.c b/file.c
 	--- a/file.c
 	+++ b/file.c
@@ -377,7 +376,6 @@ test_expect_success '-L with --word-diff' '
 	{
 	    return [-F2;-]{+F2 + 2;+}
 	}
-
 	diff --git a/file.c b/file.c
 	new file mode 100644
 	--- /dev/null
@@ -433,7 +431,6 @@ test_expect_success 'show line-log with graph' '
 	null_blob=$(test_oid zero | cut -c1-7) &&
 	qz_to_tab_space >expect <<-EOF &&
 	* $head_oid Modify func2() in file.c
-	|Z
 	| diff --git a/file.c b/file.c
 	| index $head_blob_old..$head_blob_new 100644
 	| --- a/file.c
@@ -445,7 +442,6 @@ test_expect_success 'show line-log with graph' '
 	| +    return F2 + 2;
 	|  }
 	* $root_oid Add func1() and func2() in file.c
-	ZZ
 	  diff --git a/file.c b/file.c
 	  new file mode 100644
 	  index $null_blob..$root_blob
@@ -494,23 +490,17 @@ test_expect_success '-L --find-object does not crash with merge and rename' '
 		--find-object=$(git rev-parse HEAD:file) >actual
 '
 
-# Commit-level filtering with pickaxe does not yet work for -L.
-# show_log() prints the commit header before diffcore_std() runs
-# pickaxe, so commits cannot be suppressed even when no diff pairs
-# survive filtering.  Fixing this would require deferring show_log()
-# until after diffcore_std(), which is a larger restructuring of the
-# log-tree output pipeline.
-test_expect_failure '-L -G should filter commits by pattern' '
+test_expect_success '-L -G should filter commits by pattern' '
 	git log --format="%s" --no-patch -L 1,1:file -G "nomatch" >actual &&
 	test_must_be_empty actual
 '
 
-test_expect_failure '-L -S should filter commits by pattern' '
+test_expect_success '-L -S should filter commits by pattern' '
 	git log --format="%s" --no-patch -L 1,1:file -S "nomatch" >actual &&
 	test_must_be_empty actual
 '
 
-test_expect_failure '-L --find-object should filter commits by object' '
+test_expect_success '-L --find-object should filter commits by object' '
 	git log --format="%s" --no-patch -L 1,1:file \
 		--find-object=$ZERO_OID >actual &&
 	test_must_be_empty actual
@@ -711,4 +701,41 @@ test_expect_success '-L with -G filters to diff-text matches' '
 	grep "F2 + 2" actual
 '
 
+test_expect_success '-L with --diff-filter=M excludes root commit' '
+	git checkout parent-oids &&
+	git log -L:func2:file.c --diff-filter=M --format=%s --no-patch >actual &&
+	# Root commit is an Add (A), not a Modify (M), so it should
+	# be excluded; only the modification commit remains.
+	echo "Modify func2() in file.c" >expect &&
+	test_cmp expect actual
+'
+
+test_expect_success '-L with --diff-filter=A shows only root commit' '
+	git checkout parent-oids &&
+	git log -L:func2:file.c --diff-filter=A --format=%s --no-patch >actual &&
+	echo "Add func1() and func2() in file.c" >expect &&
+	test_cmp expect actual
+'
+
+test_expect_success '-L with -S suppresses non-matching commits' '
+	git checkout parent-oids &&
+	git log -L:func2:file.c -S "F2 + 2" --format=%s --no-patch >actual &&
+	# Only the commit that changes the count of "F2 + 2" should appear.
+	echo "Modify func2() in file.c" >expect &&
+	test_cmp expect actual
+'
+
+test_expect_success '--full-diff is not yet supported with -L' '
+	test_must_fail git log -L1,24:b.c --full-diff 2>err &&
+	test_grep "does not yet support" err
+'
+
+test_expect_success '-L --oneline has no extra blank line before diff' '
+	git checkout parent-oids &&
+	git log --oneline -L:func2:file.c -1 >actual &&
+	# Oneline header on line 1, diff starts immediately on line 2
+	sed -n 2p actual >line2 &&
+	test_grep "^diff --git" line2
+'
+
 test_done
diff --git a/t/t4211/sha1/expect.parallel-change-f-to-main b/t/t4211/sha1/expect.parallel-change-f-to-main
index 65a8cc673a..6d7a201036 100644
--- a/t/t4211/sha1/expect.parallel-change-f-to-main
+++ b/t/t4211/sha1/expect.parallel-change-f-to-main
@@ -5,7 +5,6 @@ Date:   Fri Apr 12 16:16:24 2013 +0200
 
     Merge across the rename
 
-
 commit 6ce3c4ff690136099bb17e1a8766b75764726ea7
 Author: Thomas Rast <trast@student.ethz.ch>
 Date:   Thu Feb 28 10:49:50 2013 +0100
diff --git a/t/t4211/sha256/expect.parallel-change-f-to-main b/t/t4211/sha256/expect.parallel-change-f-to-main
index 3178989253..c93e03bef4 100644
--- a/t/t4211/sha256/expect.parallel-change-f-to-main
+++ b/t/t4211/sha256/expect.parallel-change-f-to-main
@@ -5,7 +5,6 @@ Date:   Fri Apr 12 16:16:24 2013 +0200
 
     Merge across the rename
 
-
 commit 4f7a58195a92c400e28a2354328587f1ff14fb77f5cf894536f17ccbc72931b9
 Author: Thomas Rast <trast@student.ethz.ch>
 Date:   Thu Feb 28 10:49:50 2013 +0100
-- 
gitgitgadget

[PATCH v2 3/3] line-log: allow non-patch diff formats with -L

[Michael Montalbo via GitGitGadget]

From: Michael Montalbo <mmontalbo@gmail.com>

Now that -L flows through log_tree_diff_flush() and diff_flush(),
metadata-only diff formats work because they only read filepair
fields (status, mode, path, oid) already set on the pre-computed
pairs.

Expand the allowlist in setup_revisions() to also accept --raw,
--name-only, --name-status, and --summary.  Diff stat formats
(--stat, --numstat, --shortstat, --dirstat) remain blocked because
they call compute_diffstat() on full blob content and would show
whole-file statistics rather than range-scoped ones.

Signed-off-by: Michael Montalbo <mmontalbo@gmail.com>
---
 Documentation/line-range-options.adoc | 10 +++---
 revision.c                            |  4 ++-
 t/t4211-line-log.sh                   | 47 +++++++++++++++++++++++++--
 3 files changed, 54 insertions(+), 7 deletions(-)

diff --git a/Documentation/line-range-options.adoc b/Documentation/line-range-options.adoc
index ecb2c79fb9..72f639b5e7 100644
--- a/Documentation/line-range-options.adoc
+++ b/Documentation/line-range-options.adoc
@@ -8,12 +8,14 @@
 	give zero or one positive revision arguments, and
 	_<start>_ and _<end>_ (or _<funcname>_) must exist in the starting revision.
 	You can specify this option more than once. Implies `--patch`.
-	Patch output can be suppressed using `--no-patch`, but other diff formats
-	(namely `--raw`, `--numstat`, `--shortstat`, `--dirstat`, `--summary`,
-	`--name-only`, `--name-status`, `--check`) are not currently implemented.
+	Patch output can be suppressed using `--no-patch`.
+	Non-patch diff formats `--raw`, `--name-only`, `--name-status`,
+	and `--summary` are supported.  Diff stat formats
+	(`--stat`, `--numstat`, `--shortstat`, `--dirstat`) are not
+	currently implemented.
 +
 Patch formatting options such as `--word-diff`, `--color-moved`,
 `--no-prefix`, and whitespace options (`-w`, `-b`) are supported,
-as are pickaxe options (`-S`, `-G`).
+as are pickaxe options (`-S`, `-G`) and `--diff-filter`.
 +
 include::line-range-format.adoc[]
diff --git a/revision.c b/revision.c
index c903f7a1b4..f26fc1f4d5 100644
--- a/revision.c
+++ b/revision.c
@@ -3181,7 +3181,9 @@ int setup_revisions(int argc, const char **argv, struct rev_info *revs, struct s
 	if (revs->line_level_traverse &&
 	    (revs->full_diff ||
 	     (revs->diffopt.output_format &
-	      ~(DIFF_FORMAT_PATCH | DIFF_FORMAT_NO_OUTPUT))))
+	      ~(DIFF_FORMAT_PATCH | DIFF_FORMAT_NO_OUTPUT |
+		DIFF_FORMAT_RAW | DIFF_FORMAT_NAME |
+		DIFF_FORMAT_NAME_STATUS | DIFF_FORMAT_SUMMARY))))
 		die(_("-L does not yet support the requested diff format"));
 
 	if (revs->expand_tabs_in_log < 0)
diff --git a/t/t4211-line-log.sh b/t/t4211-line-log.sh
index e3937138a9..4722ec3e29 100755
--- a/t/t4211-line-log.sh
+++ b/t/t4211-line-log.sh
@@ -155,8 +155,45 @@ test_expect_success '-p shows the default patch output' '
 	test_cmp expect actual
 '
 
-test_expect_success '--raw is forbidden' '
-	test_must_fail git log -L1,24:b.c --raw
+test_expect_success '--raw shows mode, oid, status and path' '
+	git log -L1,24:b.c --raw --format= >actual &&
+	test_grep "^:100644 100644 [0-9a-f]\{7\} [0-9a-f]\{7\} M	b.c$" actual &&
+	! test_grep "^diff --git" actual &&
+	! test_grep "^@@" actual
+'
+
+test_expect_success '--name-only shows path' '
+	git log -L1,24:b.c --name-only --format= >actual &&
+	test_grep "^b.c$" actual &&
+	! test_grep "^diff --git" actual &&
+	! test_grep "^@@" actual
+'
+
+test_expect_success '--name-status shows status and path' '
+	git log -L1,24:b.c --name-status --format= >actual &&
+	test_grep "^M	b.c$" actual &&
+	! test_grep "^diff --git" actual &&
+	! test_grep "^@@" actual
+'
+
+test_expect_success '--stat is not yet supported with -L' '
+	test_must_fail git log -L1,24:b.c --stat 2>err &&
+	test_grep "does not yet support" err
+'
+
+test_expect_success '--numstat is not yet supported with -L' '
+	test_must_fail git log -L1,24:b.c --numstat 2>err &&
+	test_grep "does not yet support" err
+'
+
+test_expect_success '--shortstat is not yet supported with -L' '
+	test_must_fail git log -L1,24:b.c --shortstat 2>err &&
+	test_grep "does not yet support" err
+'
+
+test_expect_success '--dirstat is not yet supported with -L' '
+	test_must_fail git log -L1,24:b.c --dirstat 2>err &&
+	test_grep "does not yet support" err
 '
 
 test_expect_success 'setup for checking fancy rename following' '
@@ -738,4 +775,10 @@ test_expect_success '-L --oneline has no extra blank line before diff' '
 	test_grep "^diff --git" line2
 '
 
+test_expect_success '--summary shows new file on root commit' '
+	git checkout parent-oids &&
+	git log -L:func2:file.c --summary --format= >actual &&
+	test_grep "create mode 100644 file.c" actual
+'
+
 test_done
-- 
gitgitgadget