Re: [PATCH] core.abbrev <off|false|no> disables abbreviations

[Junio C Hamano <gitster@pobox.com>]

From: Eric Wong <e@80x24.org>
Date: Tue, 1 Sep 2020 07:43:55 +0000
Subject: [PATCH] core.abbrev=no disables abbreviations

These allows users to write hash-agnostic scripts and configs to
disable abbreviations.  Using "-c core.abbrev=40" will be
insufficient with SHA-256, and "-c core.abbrev=64" won't work
with SHA-1 repos today.

Signed-off-by: Eric Wong <e@80x24.org>
[jc: tweaked implementation, added doc and a test]
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 Documentation/config/core.txt | 2 ++
 config.c                      | 2 ++
 t/t3200-branch.sh             | 2 ++
 3 files changed, 6 insertions(+)

diff --git a/Documentation/config/core.txt b/Documentation/config/core.txt
index 160aacad84..c04f62a54a 100644
--- a/Documentation/config/core.txt
+++ b/Documentation/config/core.txt
@@ -625,4 +625,6 @@ core.abbrev::
 	computed based on the approximate number of packed objects
 	in your repository, which hopefully is enough for
 	abbreviated object names to stay unique for some time.
+	If set to "no", no abbreviation is made and the object names
+	are shown in their full length.
 	The minimum length is 4.
diff --git a/config.c b/config.c
index 1137bd73af..4c0cf3a1c1 100644
--- a/config.c
+++ b/config.c
@@ -1217,6 +1217,8 @@ static int git_default_core_config(const char *var, const char *value, void *cb)
 			return config_error_nonbool(var);
 		if (!strcasecmp(value, "auto"))
 			default_abbrev = -1;
+		else if (!git_parse_maybe_bool_text(value))
+			default_abbrev = the_hash_algo->hexsz;
 		else {
 			int abbrev = git_config_int(var, value);
 			if (abbrev < minimum_abbrev || abbrev > the_hash_algo->hexsz)
diff --git a/t/t3200-branch.sh b/t/t3200-branch.sh
index a0b832d59e..67db316911 100755
--- a/t/t3200-branch.sh
+++ b/t/t3200-branch.sh
@@ -305,7 +305,9 @@ test_expect_success 'git branch --list -v with --abbrev' '
 
 	git branch -v --list --no-abbrev t >actual.noabbrev &&
 	git branch -v --list --abbrev=0 t >actual.0abbrev &&
+	git -c core.abbrev=no branch -v --list t >actual.noabbrev-conf &&
 	test_cmp actual.noabbrev actual.0abbrev &&
+	test_cmp actual.noabbrev actual.noabbrev-conf &&
 
 	git branch -v --list --abbrev=36 t >actual.36abbrev &&
 	# how many hexdigits are used?
-- 
2.30.0-rc1-197-gdf840da780