[PATCH v9 3/9] environment: move editor_program into repo_config_values

[Tian Yuchen <cat@malon.dev>]

The global variable 'editor_program' holds the path to the user's
preferred editor. Move 'editor_program' into
'struct repo_config_values' to continue the libification effort.

There have been discussions on whether external programs like
editors truly need to be configured on a per-repository basis within
the same process. While a single process might rarely invoke
different editors, this migration is necessary for two reasons:

1. Developers frequently use different toolchains for different
   projects. Per-repo configuration respects this.

2. Moving this string into 'repo_config_values' eliminates mutable
   global state. As the codebase moves toward becoming a long-running
   processes managing multiple repositories concurrently must
   not overwrite each other's program configurations.

No standalone getter function is introduced. Callers directly access
the field via 'repo_config_values()'. Heap memory is safely reclaimed
in 'repo_config_values_clear()'.

Mentored-by: Christian Couder <christian.couder@gmail.com>
Mentored-by: Ayush Chandekar <ayu.chandekar@gmail.com>
Mentored-by: Olamide Caleb Bello <belkid98@gmail.com>
Signed-off-by: Tian Yuchen <cat@malon.dev>
---
 editor.c      | 4 ++--
 environment.c | 7 ++++---
 environment.h | 2 +-
 3 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/editor.c b/editor.c
index fd174e6a03..07d264cba0 100644
--- a/editor.c
+++ b/editor.c
@@ -29,8 +29,8 @@ const char *git_editor(void)
 	const char *editor = getenv("GIT_EDITOR");
 	int terminal_is_dumb = is_terminal_dumb();
 
-	if (!editor && editor_program)
-		editor = editor_program;
+	if (!editor && repo_config_values(the_repository)->editor_program)
+		editor = repo_config_values(the_repository)->editor_program;
 	if (!editor && !terminal_is_dumb)
 		editor = getenv("VISUAL");
 	if (!editor)
diff --git a/environment.c b/environment.c
index 5950592d63..0a01f4761a 100644
--- a/environment.c
+++ b/environment.c
@@ -55,7 +55,6 @@ int fsync_object_files = -1;
 int use_fsync = -1;
 enum fsync_method fsync_method = FSYNC_METHOD_DEFAULT;
 enum fsync_component fsync_components = FSYNC_COMPONENTS_DEFAULT;
-char *editor_program;
 char *askpass_program;
 enum auto_crlf auto_crlf = AUTO_CRLF_FALSE;
 enum eol core_eol = EOL_UNSET;
@@ -435,8 +434,8 @@ int git_default_core_config(const char *var, const char *value,
 	}
 
 	if (!strcmp(var, "core.editor")) {
-		FREE_AND_NULL(editor_program);
-		return git_config_string(&editor_program, var, value);
+		FREE_AND_NULL(cfg->editor_program);
+		return git_config_string(&cfg->editor_program, var, value);
 	}
 
 	if (!strcmp(var, "core.commentchar") ||
@@ -723,6 +722,7 @@ void repo_config_values_init(struct repo_config_values *cfg)
 {
 	cfg->attributes_file = NULL;
 	cfg->excludes_file = NULL;
+	cfg->editor_program = NULL;
 	cfg->apply_sparse_checkout = 0;
 	cfg->branch_track = BRANCH_TRACK_REMOTE;
 	cfg->trust_ctime = 1;
@@ -753,4 +753,5 @@ void repo_config_values_clear(struct repository *repo)
 
 	FREE_AND_NULL(cfg->attributes_file);
 	FREE_AND_NULL(cfg->excludes_file);
+	FREE_AND_NULL(cfg->editor_program);
 }
diff --git a/environment.h b/environment.h
index 2e8352de7f..1ec19149cb 100644
--- a/environment.h
+++ b/environment.h
@@ -91,6 +91,7 @@ struct repo_config_values {
 	/* section "core" config values */
 	char *attributes_file;
 	char *excludes_file;
+	char *editor_program;
 	int apply_sparse_checkout;
 	int trust_ctime;
 	int check_stat;
@@ -218,7 +219,6 @@ const char *get_commit_output_encoding(void);
 extern char *git_commit_encoding;
 extern char *git_log_output_encoding;
 
-extern char *editor_program;
 extern char *askpass_program;
 
 /*
-- 
2.43.0