environment: remove the global variable 'sparse_expect_files_outside_of_patterns'

The global variable 'sparse_expect_files_outside_of_patterns' is used in
a single function named 'clear_skip_worktree_from_present_files()' in
sparse-index.c. Move its declaration inside that function, removing
unnecessary global state.

This also allows us to remove the definition '#define
USE_THE_REPOSITORY_VARIABLE' from the file 'sparse-index.c'.

This change is part of an ongoing effort to eliminate global variables,
improve modularity and help libify the codebase.

Mentored-by: Christian Couder <christian.couder@gmail.com>
Mentored-by: Ghanshyam Thakkar <shyamthakkar001@gmail.com>
Signed-off-by: Ayush Chandekar <ayu.chandekar@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: ayu-ch

config.c

@@ -1636,17 +1636,6 @@ static int git_default_core_config(const char *var, const char *value,
 	return platform_core_config(var, value, ctx, cb);
 }
 
-static int git_default_sparse_config(const char *var, const char *value)
-{
-	if (!strcmp(var, "sparse.expectfilesoutsideofpatterns")) {
-		sparse_expect_files_outside_of_patterns = git_config_bool(var, value);
-		return 0;
-	}
-
-	/* Add other config variables here and to Documentation/config/sparse.adoc. */
-	return 0;
-}
-
 static int git_default_i18n_config(const char *var, const char *value)
 {
 	if (!strcmp(var, "i18n.commitencoding")) {
@@ -1808,9 +1797,6 @@ int git_default_config(const char *var, const char *value,
 		return 0;
 	}
 
-	if (starts_with(var, "sparse."))
-		return git_default_sparse_config(var, value);
-
 	/* Add other config variables here and to Documentation/config.adoc. */
 	return 0;
 }

environment.c

@@ -64,7 +64,6 @@ enum push_default_type push_default = PUSH_DEFAULT_UNSPECIFIED;
 #endif
 enum object_creation_mode object_creation_mode = OBJECT_CREATION_MODE;
 int grafts_keep_true_parents;
-int sparse_expect_files_outside_of_patterns;
 int merge_log_config = -1;
 int precomposed_unicode = -1; /* see probe_utf8_pathname_composition() */
 unsigned long pack_size_limit_cfg;

environment.h

@@ -160,8 +160,6 @@ extern int precomposed_unicode;
 extern int protect_hfs;
 extern int protect_ntfs;
 
-extern int sparse_expect_files_outside_of_patterns;
-
 enum rebase_setup_type {
 	AUTOREBASE_NEVER = 0,
 	AUTOREBASE_LOCAL,

sparse-index.c

@@ -1,4 +1,3 @@
-#define USE_THE_REPOSITORY_VARIABLE
 #define DISABLE_SIGN_COMPARE_WARNINGS
 
 #include "git-compat-util.h"
@@ -668,6 +667,9 @@ static void clear_skip_worktree_from_present_files_full(struct index_state *ista
 
 void clear_skip_worktree_from_present_files(struct index_state *istate)
 {
+	int sparse_expect_files_outside_of_patterns = 0;
+	repo_config_get_bool(istate->repo, "sparse.expectfilesoutsideofpatterns", 
+		&sparse_expect_files_outside_of_patterns);
 	if (!istate->repo->settings.sparse_checkout ||
 	    sparse_expect_files_outside_of_patterns)
 		return;