[PATCH 3/4] config: add repo_config_set_worktree_gently()

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

From: Derrick Stolee <dstolee@microsoft.com>

When adding config values to the worktree config, we might enable the
extensions.worktreeConfig setting and create the config.worktree file
for the first time. When the base repository is bare, this creates a
change of behavior for determining if the worktree is bare or not. A
worktree off of a bare repository is assumed to be non-bare when
extensions.worktreeConfig is disabled. When extensions.worktreeConfig is
enabled but config.worktree is empty, the worktree is considered bare
because the base repo's core.bare=true setting is used.

To avoid issues like this, create a helper that initializes all the
right settings in the correct order. A caller will be added in the next
change.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
---
 config.c | 27 +++++++++++++++++++++++++++
 config.h |  6 ++++++
 2 files changed, 33 insertions(+)

diff --git a/config.c b/config.c
index 9c9eef16018..67f3d5015ef 100644
--- a/config.c
+++ b/config.c
@@ -2880,6 +2880,33 @@ 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)
+{
+	int res;
+	const char *config_filename = repo_git_path(r, "config.worktree");
+
+	/*
+	 * Ensure that core.bare reflects the current worktree, since the
+	 * logic for is_bare_repository() changes if extensions.worktreeConfig
+	 * is disabled.
+	 */
+	if ((res = git_config_set_multivar_in_file_gently(config_filename, "core.bare",
+							  r->worktree ? "false" : "true",
+							  NULL, 0))) {
+		error(_("unable to set core.bare setting in worktree config"));
+		return res;
+	}
+	if (upgrade_repository_format(r, 1) < 0)
+		return error(_("unable to upgrade repository format to enable worktreeConfig"));
+	if ((res = git_config_set_gently("extensions.worktreeConfig", "true"))) {
+		error(_("failed to set extensions.worktreeConfig setting"));
+		return res;
+	}
+
+	return git_config_set_multivar_in_file_gently(config_filename, 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..d8db420849e 100644
--- a/config.h
+++ b/config.h
@@ -253,6 +253,12 @@ 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.
+ */
+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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