[PATCH 22/30] pack-objects: introduce GIT_TEST_PACK_PATH_WALK

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

From: Derrick Stolee <stolee@gmail.com>

There are many tests that validate whether 'git pack-objects' works as
expected. Instead of duplicating these tests, add a new test environment
variable, GIT_TEST_PACK_PATH_WALK, that implies --path-walk by default
when specified.

This was useful in testing the implementation of the --path-walk
implementation, especially in conjunction with test such as:

 - t5322-pack-objects-sparse.sh : This demonstrates the effectiveness of
   the --sparse option and how it combines with --path-walk.

RFC TODO: list other helpful test cases, as well as the ones where the
behavior breaks if this is enabled...

Signed-off-by: Derrick Stolee <stolee@gmail.com>
---
 builtin/pack-objects.c | 1 +
 t/README               | 4 ++++
 2 files changed, 5 insertions(+)

diff --git a/builtin/pack-objects.c b/builtin/pack-objects.c
index b1d684c3417..b9fe1b1fbd5 100644
--- a/builtin/pack-objects.c
+++ b/builtin/pack-objects.c
@@ -4534,6 +4534,7 @@ int cmd_pack_objects(int argc, const char **argv, const char *prefix)
 
 	disable_replace_refs();
 
+	path_walk = git_env_bool("GIT_TEST_PACK_PATH_WALK", 0);
 	sparse = git_env_bool("GIT_TEST_PACK_SPARSE", -1);
 	if (the_repository->gitdir) {
 		prepare_repo_settings(the_repository);
diff --git a/t/README b/t/README
index 44c02d81298..a5d7d0239e0 100644
--- a/t/README
+++ b/t/README
@@ -433,6 +433,10 @@ GIT_TEST_PACK_SPARSE=<boolean> if disabled will default the pack-objects
 builtin to use the non-sparse object walk. This can still be overridden by
 the --sparse command-line argument.
 
+GIT_TEST_PACK_PATH_WALK=<boolean> if enabled will default the pack-objects
+builtin to use the path-walk API for the object walk. This can still be
+overridden by the --no-path-walk command-line argument.
+
 GIT_TEST_PRELOAD_INDEX=<boolean> exercises the preload-index code path
 by overriding the minimum number of cache entries required per thread.
 
-- 
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