[RFC/PATCH v3 09/16] Add GIT_NO_EXTERNAL_ODB env variable

[Christian Couder <christian.couder@gmail.com>]

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
---
 cache.h        | 9 +++++++++
 environment.c  | 4 ++++
 external-odb.c | 6 ++++++
 sha1_file.c    | 3 +++
 4 files changed, 22 insertions(+)

diff --git a/cache.h b/cache.h
index b419b9b7ce..503b618a1f 100644
--- a/cache.h
+++ b/cache.h
@@ -422,6 +422,7 @@ static inline enum object_type object_type(unsigned int mode)
 #define CEILING_DIRECTORIES_ENVIRONMENT "GIT_CEILING_DIRECTORIES"
 #define NO_REPLACE_OBJECTS_ENVIRONMENT "GIT_NO_REPLACE_OBJECTS"
 #define GIT_REPLACE_REF_BASE_ENVIRONMENT "GIT_REPLACE_REF_BASE"
+#define NO_EXTERNAL_ODB_ENVIRONMENT "GIT_NO_EXTERNAL_ODB"
 #define GITATTRIBUTES_FILE ".gitattributes"
 #define INFOATTRIBUTES_FILE "info/attributes"
 #define ATTRIBUTE_MACRO_PREFIX "[attr]"
@@ -698,6 +699,14 @@ void reset_shared_repository(void);
 extern int check_replace_refs;
 extern char *git_replace_ref_base;
 
+/*
+ * Do external odbs need to be used this run?  This variable is
+ * initialized to true unless $GIT_NO_EXTERNAL_ODB is set, but it
+ * maybe set to false by some commands that do not want external
+ * odbs to be active.
+ */
+extern int use_external_odb;
+
 extern int fsync_object_files;
 extern int core_preload_index;
 extern int core_apply_sparse_checkout;
diff --git a/environment.c b/environment.c
index 0935ec696e..8aecdd0544 100644
--- a/environment.c
+++ b/environment.c
@@ -47,6 +47,7 @@ const char *excludes_file;
 enum auto_crlf auto_crlf = AUTO_CRLF_FALSE;
 int check_replace_refs = 1;
 char *git_replace_ref_base;
+int use_external_odb = 1;
 enum eol core_eol = EOL_UNSET;
 enum safe_crlf safe_crlf = SAFE_CRLF_WARN;
 unsigned whitespace_rule_cfg = WS_DEFAULT_RULE;
@@ -120,6 +121,7 @@ const char * const local_repo_env[] = {
 	INDEX_ENVIRONMENT,
 	NO_REPLACE_OBJECTS_ENVIRONMENT,
 	GIT_REPLACE_REF_BASE_ENVIRONMENT,
+	NO_EXTERNAL_ODB_ENVIRONMENT,
 	GIT_PREFIX_ENVIRONMENT,
 	GIT_SUPER_PREFIX_ENVIRONMENT,
 	GIT_SHALLOW_FILE_ENVIRONMENT,
@@ -185,6 +187,8 @@ static void setup_git_env(void)
 	replace_ref_base = getenv(GIT_REPLACE_REF_BASE_ENVIRONMENT);
 	git_replace_ref_base = xstrdup(replace_ref_base ? replace_ref_base
 							  : "refs/replace/");
+	if (getenv(NO_EXTERNAL_ODB_ENVIRONMENT))
+		use_external_odb = 0;
 	namespace = expand_namespace(getenv(GIT_NAMESPACE_ENVIRONMENT));
 	namespace_len = strlen(namespace);
 	shallow_file = getenv(GIT_SHALLOW_FILE_ENVIRONMENT);
diff --git a/external-odb.c b/external-odb.c
index 6dd7b2548b..a980fbfbf2 100644
--- a/external-odb.c
+++ b/external-odb.c
@@ -63,6 +63,9 @@ int external_odb_has_object(const unsigned char *sha1)
 {
 	struct odb_helper *o;
 
+	if (!use_external_odb)
+		return 0;
+
 	external_odb_init();
 
 	for (o = helpers; o; o = o->next)
@@ -133,6 +136,9 @@ int external_odb_write_object(const void *buf, unsigned long len,
 {
 	struct odb_helper *o;
 
+	if (!use_external_odb)
+		return 1;
+
 	/* For now accept only blobs */
 	if (strcmp(type, "blob"))
 		return 1;
diff --git a/sha1_file.c b/sha1_file.c
index 3532c1c598..92f1244205 100644
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -556,6 +556,9 @@ void prepare_external_alt_odb(void)
 	static int linked_external;
 	const char *path;
 
+	if (!use_external_odb)
+		return;
+
 	if (linked_external)
 		return;
 
-- 
2.11.0.rc2.37.geb49ca6