[PATCH v2 4/5] config: add repo_config_set_worktree_gently()

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

From: Derrick Stolee <dstolee@microsoft.com>

The previous change added upgrade_to_worktree_config() to assist
creating a worktree-specific config for the first time. However, this
requires every config writer to care about that upgrade before writing
to the worktree-specific config. In addition, callers need to know how
to generate the name of the config.worktree file and pass it to the
config API.

To assist, create a new repo_config_set_worktree_gently() method in the
config API that handles the upgrade_to_worktree_config() method in
addition to assigning the value in the worktree-specific config. This
will be consumed by an upcoming change.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
---
 config.c | 10 ++++++++++
 config.h |  7 +++++++
 2 files changed, 17 insertions(+)

diff --git a/config.c b/config.c
index 9c9eef16018..81f3a689c11 100644
--- a/config.c
+++ b/config.c
@@ -21,6 +21,7 @@
 #include "dir.h"
 #include "color.h"
 #include "refs.h"
+#include "worktree.h"
 
 struct config_source {
 	struct config_source *prev;
@@ -2880,6 +2881,15 @@ int git_config_set_gently(const char *key, const char *value)
 	return git_config_set_multivar_gently(key, value, NULL, 0);
 }
 
+int repo_config_set_worktree_gently(struct repository *r,
+				    const char *key, const char *value)
+{
+	return upgrade_to_worktree_config(r) ||
+	       git_config_set_multivar_in_file_gently(
+			 repo_git_path(r, "config.worktree"),
+			 key, value, NULL, 0);
+}
+
 void git_config_set(const char *key, const char *value)
 {
 	repo_config_set(the_repository, key, value);
diff --git a/config.h b/config.h
index 5531fc018e3..b05c51b3528 100644
--- a/config.h
+++ b/config.h
@@ -253,6 +253,13 @@ void git_config_set_in_file(const char *, const char *, const char *);
 
 int git_config_set_gently(const char *, const char *);
 
+/**
+ * Write a config value into the config.worktree file for the current
+ * worktree. This will initialize extensions.worktreeConfig if necessary,
+ * which might trigger some changes to the root repository's config file.
+ */
+int repo_config_set_worktree_gently(struct repository *, const char *, const char *);
+
 /**
  * write config values to `.git/config`, takes a key/value pair as parameter.
  */
-- 
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