[Outreachy PATCH v2] environment: move "core.attributesFile" into repo-setting

[Olamide Caleb Bello <belkid98@gmail.com>]

When handling multiple repositories within the same process, relying on
global state for accessing the "core.attributesFile" configuration can
lead to incorrect values being used. It also makes it harder to isolate
repositories and hinders the libification of git.
The functions `bootstrap_attr_stack()` and `git_attr_val_system()`
retrieve "core.attributesFile" via `git_attr_global_file()`
which reads from global state `git_attributes_file`.

Move the "core.attributesFile" configuration into the
`struct repo_settings` instead of relying on the global state.
A new function `repo_settings_get_attributesfile_path()` is added
and used to retrieve this setting in a repository-scoped manner.
The functions to retrieve "core.attributesFile" are replaced with
the new accessor function `repo_settings_get_attributesfile_path()`
This improves multi-repository behaviour and aligns with the goal of
libifying of Git.

Note that in `bootstrap_attr_stack()`, the `index_state` is used only
if it exists, else we default to `the_repository`.

Based-on-patch-by: Ayush Chandekar <ayu.chandekar@gmail.com>
Mentored-by: Christian Couder <christian.couder@gmail.com>
Mentored-by: Usman Akinyemi <usmanakinyemi202@gmail.com>
Signed-off-by: Olamide Caleb Bello <belkid98@gmail.com>
---
The link to the GitHub CI is provided below
https://github.com/git/git/actions/runs/20661817110

Changes in v2:
--------------
- Renamed the variable in the repo-settings struct to `attributes_file_path`
- Modified the comment section of the accessor function declaration to
  indicate the core.attributesFile is read via repo config.

Range diff vs v1:
-----------------
1:  4975f77cde ! 1:  fc1dbec892 environment: move "core.attributesfile" into repo-setting
    @@ Commit message
         Note that in `bootstrap_attr_stack()`, the `index_state` is used only
         if it exists, else we default to `the_repository`.
     
    -    Reported-by: Ayush Chandekar <ayu.chandekar@gmail.com>
    +    Based-on-patch-by: Ayush Chandekar <ayu.chandekar@gmail.com>
         Mentored-by: Christian Couder <christian.couder@gmail.com>
         Mentored-by: Usman Akinyemi <usmanakinyemi202@gmail.com>
         Signed-off-by: Olamide Caleb Bello <belkid98@gmail.com>
    @@ attr.c: static void bootstrap_attr_stack(struct index_state *istate,
      	if (*stack)
      		return;
     @@ attr.c: static void bootstrap_attr_stack(struct index_state *istate,
    - 		push_stack(stack, e, NULL, 0);
      	}
      
    --	/* home directory */
    + 	/* home directory */
     -	if (git_attr_global_file()) {
     -		e = read_attr_from_file(git_attr_global_file(), flags);
     +	if (istate && istate->repo)
    @@ repo-settings.c: void repo_settings_clear(struct repository *r)
      	struct repo_settings empty = REPO_SETTINGS_INIT;
      	FREE_AND_NULL(r->settings.fsmonitor);
      	FREE_AND_NULL(r->settings.hooks_path);
    -+	FREE_AND_NULL(r->settings.git_attributes_file);
    ++	FREE_AND_NULL(r->settings.attributes_file_path);
      	r->settings = empty;
      }
      
    @@ repo-settings.c: void repo_settings_reset_shared_repository(struct repository *r
      }
     +const char *repo_settings_get_attributesfile_path(struct repository *repo)
     +{
    -+	if (!repo->settings.git_attributes_file) {
    -+		if (repo_config_get_pathname(repo, "core.attributesfile", &repo->settings.git_attributes_file))
    -+			repo->settings.git_attributes_file = xdg_config_home("attributes");
    ++	if (!repo->settings.attributes_file_path) {
    ++		if (repo_config_get_pathname(repo, "core.attributesfile", &repo->settings.attributes_file_path))
    ++			repo->settings.attributes_file_path = xdg_config_home("attributes");
     +	}
    -+	return repo->settings.git_attributes_file;
    ++	return repo->settings.attributes_file_path;
     +}
     
      ## repo-settings.h ##
    @@ repo-settings.h: struct repo_settings {
      	unsigned long big_file_threshold;
      
      	char *hooks_path;
    -+	char *git_attributes_file;
    ++	char *attributes_file_path;
      };
      #define REPO_SETTINGS_INIT { \
      	.shared_repository = -1, \
    @@ repo-settings.h: int repo_settings_get_shared_repository(struct repository *repo
     +/*
     + * Read the value for "core.attributesfile".
     + * Defaults to xdg_config_home("attributes") if the core.attributesfile
    -+ * isn't available.
    ++ * which is set via repo config isn't available.
     + */
     +const char *repo_settings_get_attributesfile_path(struct repository *repo);
     +

 attr.c          | 19 +++++++++----------
 attr.h          |  3 ---
 builtin/var.c   |  2 +-
 environment.c   |  6 ------
 environment.h   |  1 -
 repo-settings.c | 10 ++++++++++
 repo-settings.h |  8 ++++++++
 7 files changed, 28 insertions(+), 21 deletions(-)

diff --git a/attr.c b/attr.c
index 4999b7e09d..b081400c18 100644
--- a/attr.c
+++ b/attr.c
@@ -879,14 +879,6 @@ const char *git_attr_system_file(void)
 	return system_wide;
 }
 
-const char *git_attr_global_file(void)
-{
-	if (!git_attributes_file)
-		git_attributes_file = xdg_config_home("attributes");
-
-	return git_attributes_file;
-}
-
 int git_attr_system_is_enabled(void)
 {
 	return !git_env_bool("GIT_ATTR_NOSYSTEM", 0);
@@ -912,6 +904,8 @@ static void bootstrap_attr_stack(struct index_state *istate,
 {
 	struct attr_stack *e;
 	unsigned flags = READ_ATTR_MACRO_OK;
+	const char *attributes_file_path;
+	struct repository *repo;
 
 	if (*stack)
 		return;
@@ -927,8 +921,13 @@ static void bootstrap_attr_stack(struct index_state *istate,
 	}
 
 	/* home directory */
-	if (git_attr_global_file()) {
-		e = read_attr_from_file(git_attr_global_file(), flags);
+	if (istate && istate->repo)
+		repo = istate->repo;
+	else
+		repo = the_repository;
+	attributes_file_path = repo_settings_get_attributesfile_path(repo);
+	if (attributes_file_path) {
+		e = read_attr_from_file(attributes_file_path, flags);
 		push_stack(stack, e, NULL, 0);
 	}
 
diff --git a/attr.h b/attr.h
index a04a521092..956ce6ba62 100644
--- a/attr.h
+++ b/attr.h
@@ -232,9 +232,6 @@ void attr_start(void);
 /* Return the system gitattributes file. */
 const char *git_attr_system_file(void);
 
-/* Return the global gitattributes file, if any. */
-const char *git_attr_global_file(void);
-
 /* Return whether the system gitattributes file is enabled and should be used. */
 int git_attr_system_is_enabled(void);
 
diff --git a/builtin/var.c b/builtin/var.c
index cc3a43cde2..fd577f2930 100644
--- a/builtin/var.c
+++ b/builtin/var.c
@@ -72,7 +72,7 @@ static char *git_attr_val_system(int ident_flag UNUSED)
 
 static char *git_attr_val_global(int ident_flag UNUSED)
 {
-	char *file = xstrdup_or_null(git_attr_global_file());
+	char *file = xstrdup_or_null(repo_settings_get_attributesfile_path(the_repository));
 	if (file) {
 		normalize_path_copy(file, file);
 		return file;
diff --git a/environment.c b/environment.c
index a770b5921d..ed7d8f42d9 100644
--- a/environment.c
+++ b/environment.c
@@ -53,7 +53,6 @@ char *git_commit_encoding;
 char *git_log_output_encoding;
 char *apply_default_whitespace;
 char *apply_default_ignorewhitespace;
-char *git_attributes_file;
 int zlib_compression_level = Z_BEST_SPEED;
 int pack_compression_level = Z_DEFAULT_COMPRESSION;
 int fsync_object_files = -1;
@@ -363,11 +362,6 @@ static int git_default_core_config(const char *var, const char *value,
 		return 0;
 	}
 
-	if (!strcmp(var, "core.attributesfile")) {
-		FREE_AND_NULL(git_attributes_file);
-		return git_config_pathname(&git_attributes_file, var, value);
-	}
-
 	if (!strcmp(var, "core.bare")) {
 		is_bare_repository_cfg = git_config_bool(var, value);
 		return 0;
diff --git a/environment.h b/environment.h
index 51898c99cd..3512a7072e 100644
--- a/environment.h
+++ b/environment.h
@@ -152,7 +152,6 @@ extern int assume_unchanged;
 extern int warn_on_object_refname_ambiguity;
 extern char *apply_default_whitespace;
 extern char *apply_default_ignorewhitespace;
-extern char *git_attributes_file;
 extern int zlib_compression_level;
 extern int pack_compression_level;
 extern unsigned long pack_size_limit_cfg;
diff --git a/repo-settings.c b/repo-settings.c
index 195c24e9c0..cc53a3cd3b 100644
--- a/repo-settings.c
+++ b/repo-settings.c
@@ -5,6 +5,7 @@
 #include "midx.h"
 #include "pack-objects.h"
 #include "setup.h"
+#include "path.h"
 
 static void repo_cfg_bool(struct repository *r, const char *key, int *dest,
 			  int def)
@@ -158,6 +159,7 @@ void repo_settings_clear(struct repository *r)
 	struct repo_settings empty = REPO_SETTINGS_INIT;
 	FREE_AND_NULL(r->settings.fsmonitor);
 	FREE_AND_NULL(r->settings.hooks_path);
+	FREE_AND_NULL(r->settings.attributes_file_path);
 	r->settings = empty;
 }
 
@@ -230,3 +232,11 @@ void repo_settings_reset_shared_repository(struct repository *repo)
 {
 	repo->settings.shared_repository_initialized = 0;
 }
+const char *repo_settings_get_attributesfile_path(struct repository *repo)
+{
+	if (!repo->settings.attributes_file_path) {
+		if (repo_config_get_pathname(repo, "core.attributesfile", &repo->settings.attributes_file_path))
+			repo->settings.attributes_file_path = xdg_config_home("attributes");
+	}
+	return repo->settings.attributes_file_path;
+}
diff --git a/repo-settings.h b/repo-settings.h
index d477885561..1209e1db83 100644
--- a/repo-settings.h
+++ b/repo-settings.h
@@ -68,6 +68,7 @@ struct repo_settings {
 	unsigned long big_file_threshold;
 
 	char *hooks_path;
+	char *attributes_file_path;
 };
 #define REPO_SETTINGS_INIT { \
 	.shared_repository = -1, \
@@ -99,4 +100,11 @@ int repo_settings_get_shared_repository(struct repository *repo);
 void repo_settings_set_shared_repository(struct repository *repo, int value);
 void repo_settings_reset_shared_repository(struct repository *repo);
 
+/*
+ * Read the value for "core.attributesfile".
+ * Defaults to xdg_config_home("attributes") if the core.attributesfile
+ * which is set via repo config isn't available.
+ */
+const char *repo_settings_get_attributesfile_path(struct repository *repo);
+
 #endif /* REPO_SETTINGS_H */
-- 
2.52.0.210.g7f9f2609ac.dirty