[PATCH v4 4/5] rev-list: support NUL-delimited --boundary option

[Justin Tobler <jltobler@gmail.com>]

The `--boundary` option for git-rev-list(1) prints boundary objects
found while performing the object walk in the form:

        $ git rev-list --boundary <rev>
        -<oid> LF

Add support for printing boundary objects in a NUL-delimited format when
the `-z` option is enabled.

        $ git rev-list -z --boundary <rev>
        <oid> NUL boundary=yes NUL

In this mode, instead of prefixing the boundary OID with '-', a separate
`boundary=yes` token/value pair is appended.

Signed-off-by: Justin Tobler <jltobler@gmail.com>
---
 Documentation/rev-list-options.adoc | 12 +++++++-----
 builtin/rev-list.c                  |  9 +++++++--
 t/t6000-rev-list-misc.sh            | 16 ++++++++++++++++
 3 files changed, 30 insertions(+), 7 deletions(-)

diff --git a/Documentation/rev-list-options.adoc b/Documentation/rev-list-options.adoc
index aef83813b8..3fc9902d6b 100644
--- a/Documentation/rev-list-options.adoc
+++ b/Documentation/rev-list-options.adoc
@@ -371,17 +371,19 @@ ifdef::git-rev-list[]
 <OID> NUL [<token>=<value> NUL]...
 -----------------------------------------------------------------------
 +
-Additional object metadata, such as object paths, is printed using the
-`<token>=<value>` form. Token values are printed as-is without any
-encoding/truncation. An OID entry never contains a '=' character and thus
-is used to signal the start of a new object record. Examples:
+Additional object metadata, such as object paths or boundary objects, is
+printed using the `<token>=<value>` form. Token values are printed as-is
+without any encoding/truncation. An OID entry never contains a '=' character
+and thus is used to signal the start of a new object record. Examples:
 +
 -----------------------------------------------------------------------
 <OID> NUL
 <OID> NUL path=<path> NUL
+<OID> NUL boundary=yes NUL
 -----------------------------------------------------------------------
 +
-This mode is only compatible with the `--objects` output option.
+This mode is only compatible with the `--objects` and `--boundary` output
+options.
 endif::git-rev-list[]
 
 History Simplification
diff --git a/builtin/rev-list.c b/builtin/rev-list.c
index 17de99d9ca..bcb880f109 100644
--- a/builtin/rev-list.c
+++ b/builtin/rev-list.c
@@ -240,13 +240,18 @@ static void show_commit(struct commit *commit, void *data)
 		fputs(info->header_prefix, stdout);
 
 	if (revs->include_header) {
-		if (!revs->graph)
+		if (!revs->graph && line_term)
 			fputs(get_revision_mark(revs, commit), stdout);
 		if (revs->abbrev_commit && revs->abbrev)
 			fputs(repo_find_unique_abbrev(the_repository, &commit->object.oid, revs->abbrev),
 			      stdout);
 		else
 			fputs(oid_to_hex(&commit->object.oid), stdout);
+
+		if (!line_term) {
+			if (commit->object.flags & BOUNDARY)
+				printf("%cboundary=yes", info_term);
+		}
 	}
 	if (revs->print_parents) {
 		struct commit_list *parents = commit->parents;
@@ -778,7 +783,7 @@ int cmd_rev_list(int argc,
 		if (revs.graph || revs.verbose_header || show_disk_usage ||
 		    info.show_timestamp || info.header_prefix || bisect_list ||
 		    use_bitmap_index || revs.edge_hint || revs.left_right ||
-		    revs.cherry_mark || arg_missing_action || revs.boundary)
+		    revs.cherry_mark || arg_missing_action)
 			die(_("-z option used with unsupported option"));
 	}
 
diff --git a/t/t6000-rev-list-misc.sh b/t/t6000-rev-list-misc.sh
index 886e2fc710..33881274a4 100755
--- a/t/t6000-rev-list-misc.sh
+++ b/t/t6000-rev-list-misc.sh
@@ -217,4 +217,20 @@ test_expect_success 'rev-list -z --objects' '
 	test_cmp expect actual
 '
 
+test_expect_success 'rev-list -z --boundary' '
+	test_when_finished rm -rf repo &&
+
+	git init repo &&
+	test_commit -C repo 1 &&
+	test_commit -C repo 2 &&
+
+	oid1=$(git -C repo rev-parse HEAD~) &&
+	oid2=$(git -C repo rev-parse HEAD) &&
+
+	printf "%s\0%s\0boundary=yes\0" "$oid2" "$oid1" >expect &&
+	git -C repo rev-list -z --boundary HEAD~.. >actual &&
+
+	test_cmp expect actual
+'
+
 test_done
-- 
2.49.0.rc2