[PATCH] log: add log.excludeDecoration config option

["Derrick Stolee via GitGitGadget" <gitgitgadget@gmail.com>]

From: Derrick Stolee <dstolee@microsoft.com>

In 'git log', the --decorate-refs-exclude option appends a pattern
to a string_list. This list is used to prevent showing some refs
in the decoration output, or even by --simplify-by-decoration.

Users may want to use their refs space to store utility refs that
should not appear in the decoration output. For example, Scalar [1]
runs a background fetch but places the "new" refs inside the
refs/scalar/hidden/<remote>/* refspace instead of refs/<remote>/*
to avoid updating remote refs when the user is not looking. However,
these "hidden" refs appear during regular 'git log' queries.

A similar idea to use "hidden" refs is under consideration for core
Git [2].

Add the 'log.excludeDecoration' config option so users can exclude
some refs from decorations by default instead of needing to use
--decorate-refs-exclude manually. The config value is multi-valued
much like the command-line option.

There are several tests in t4202-log.sh that test the
--decorate-refs-(include|exclude) options, so these are extended.
Since the expected output is already stored as a file, simply add
new calls that replace a "--decorate-refs-exclude" option with an
in-line config setting.

[1] https://github.com/microsoft/scalar
[2] https://lore.kernel.org/git/77b1da5d3063a2404cd750adfe3bb8be9b6c497d.1585946894.git.gitgitgadget@gmail.com/

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
---
    log: add log.excludeDecoration config option
    
    This was something hinted at in the "fetch" step of the background
    maintenance RFC. Should be a relatively minor addition to our config
    options.
    
    We definitely want this feature for microsoft/git (we would set
    log.excludeDecoration=refs/scalar/* in all Scalar repos), but we will
    wait for feedback from the community.
    
    Thanks, -Stolee

Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-610%2Fderrickstolee%2Flog-exclude-decoration-v1
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-610/derrickstolee/log-exclude-decoration-v1
Pull-Request: https://github.com/gitgitgadget/git/pull/610

 Documentation/config/log.txt |  5 +++++
 builtin/log.c                | 14 ++++++++++++++
 t/t4202-log.sh               | 22 ++++++++++++++++++++++
 3 files changed, 41 insertions(+)

diff --git a/Documentation/config/log.txt b/Documentation/config/log.txt
index e9e1e397f3f..1a158324f79 100644
--- a/Documentation/config/log.txt
+++ b/Documentation/config/log.txt
@@ -18,6 +18,11 @@ log.decorate::
 	names are shown. This is the same as the `--decorate` option
 	of the `git log`.
 
+log.excludeDecoration::
+	Exclude the specified patterns from the log decorations. This multi-
+	valued config option is the same as the `--decorate-refs-exclude`
+	option of `git log`.
+
 log.follow::
 	If `true`, `git log` will act as if the `--follow` option was used when
 	a single <path> is given.  This has the same limitations as `--follow`,
diff --git a/builtin/log.c b/builtin/log.c
index 83a4a6188e2..d7d1d5b7143 100644
--- a/builtin/log.c
+++ b/builtin/log.c
@@ -236,7 +236,21 @@ static void cmd_log_init_finish(int argc, const char **argv, const char *prefix,
 	}
 
 	if (decoration_style) {
+		const struct string_list *config_exclude =
+			repo_config_get_value_multi(the_repository,
+						    "log.excludeDecoration");
+
+		if (config_exclude) {
+			struct string_list_item *item;
+			for (item = config_exclude->items;
+			     item && item < config_exclude->items + config_exclude->nr;
+			     item++)
+				string_list_append(&decorate_refs_exclude,
+						item->string);
+		}
+
 		rev->show_decorations = 1;
+
 		load_ref_decorations(&decoration_filter, decoration_style);
 	}
 
diff --git a/t/t4202-log.sh b/t/t4202-log.sh
index 0f766ba65f5..b5de449e510 100755
--- a/t/t4202-log.sh
+++ b/t/t4202-log.sh
@@ -787,6 +787,9 @@ test_expect_success 'decorate-refs-exclude with glob' '
 	EOF
 	git log -n6 --decorate=short --pretty="tformat:%f%d" \
 		--decorate-refs-exclude="heads/octopus*" >actual &&
+	test_cmp expect.decorate actual &&
+	git -c log.excludeDecoration="heads/octopus*" log \
+		-n6 --decorate=short --pretty="tformat:%f%d" >actual &&
 	test_cmp expect.decorate actual
 '
 
@@ -801,6 +804,9 @@ test_expect_success 'decorate-refs-exclude without globs' '
 	EOF
 	git log -n6 --decorate=short --pretty="tformat:%f%d" \
 		--decorate-refs-exclude="tags/reach" >actual &&
+	test_cmp expect.decorate actual &&
+	git -c log.excludeDecoration="tags/reach" log \
+		-n6 --decorate=short --pretty="tformat:%f%d" >actual &&
 	test_cmp expect.decorate actual
 '
 
@@ -816,6 +822,14 @@ test_expect_success 'multiple decorate-refs-exclude' '
 	git log -n6 --decorate=short --pretty="tformat:%f%d" \
 		--decorate-refs-exclude="heads/octopus*" \
 		--decorate-refs-exclude="tags/reach" >actual &&
+	test_cmp expect.decorate actual &&
+	git -c log.excludeDecoration="heads/octopus*" \
+		-c log.excludeDecoration="tags/reach" log \
+		-n6 --decorate=short --pretty="tformat:%f%d" >actual &&
+	test_cmp expect.decorate actual &&
+	git -c log.excludeDecoration="heads/octopus*" log \
+		--decorate-refs-exclude="tags/reach" \
+		-n6 --decorate=short --pretty="tformat:%f%d" >actual &&
 	test_cmp expect.decorate actual
 '
 
@@ -831,6 +845,10 @@ test_expect_success 'decorate-refs and decorate-refs-exclude' '
 	git log -n6 --decorate=short --pretty="tformat:%f%d" \
 		--decorate-refs="heads/*" \
 		--decorate-refs-exclude="heads/oc*" >actual &&
+	test_cmp expect.decorate actual &&
+	git -c log.excludeDecoration="heads/oc*" log \
+		--decorate-refs="heads/*" \
+		-n6 --decorate=short --pretty="tformat:%f%d" >actual &&
 	test_cmp expect.decorate actual
 '
 
@@ -846,6 +864,10 @@ test_expect_success 'decorate-refs-exclude and simplify-by-decoration' '
 	git log -n6 --decorate=short --pretty="tformat:%f%d" \
 		--decorate-refs-exclude="*octopus*" \
 		--simplify-by-decoration >actual &&
+	test_cmp expect.decorate actual &&
+	git -c log.excludeDecoration="*octopus*" log \
+		-n6 --decorate=short --pretty="tformat:%f%d" \
+		--simplify-by-decoration >actual &&
 	test_cmp expect.decorate actual
 '
 

base-commit: 274b9cc25322d9ee79aa8e6d4e86f0ffe5ced925
-- 
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