Merge branch 'cc/replace'

* cc/replace:
  Documentation: talk a little bit about GIT_NO_REPLACE_OBJECTS
  Documentation: fix typos and spelling in replace documentation
  replace: use a GIT_NO_REPLACE_OBJECTS env variable

Documentation/git-replace.txt

@@ -17,31 +17,35 @@ DESCRIPTION
 Adds a 'replace' reference in `.git/refs/replace/`
 
 The name of the 'replace' reference is the SHA1 of the object that is
-replaced. The content of the replace reference is the SHA1 of the
+replaced. The content of the 'replace' reference is the SHA1 of the
 replacement object.
 
-Unless `-f` is given, the replace reference must not yet exist in
+Unless `-f` is given, the 'replace' reference must not yet exist in
 `.git/refs/replace/` directory.
 
-Replace references will be used by default by all git commands except
-those doing reachability traversal (prune, pack transfer and fsck).
+Replacement references will be used by default by all git commands
+except those doing reachability traversal (prune, pack transfer and
+fsck).
 
-It is possible to disable use of replacement refs for any command
-using the --no-replace-objects option just after "git".
+It is possible to disable use of replacement references for any
+command using the `--no-replace-objects` option just after 'git'.
 
-For example if commit "foo" has been replaced by commit "bar":
+For example if commit 'foo' has been replaced by commit 'bar':
 
 ------------------------------------------------
-$ git --no-replace-object cat-file commit foo
+$ git --no-replace-objects cat-file commit foo
 ------------------------------------------------
 
-show information about commit "foo", while:
+shows information about commit 'foo', while:
 
 ------------------------------------------------
 $ git cat-file commit foo
 ------------------------------------------------
 
-show information about commit "bar".
+shows information about commit 'bar'.
+
+The 'GIT_NO_REPLACE_OBJECTS' environment variable can be set to
+achieve the same effect as the `--no-replace-objects` option.
 
 OPTIONS
 -------

cache.h

@@ -369,6 +369,7 @@ static inline enum object_type object_type(unsigned int mode)
 #define CONFIG_ENVIRONMENT "GIT_CONFIG"
 #define EXEC_PATH_ENVIRONMENT "GIT_EXEC_PATH"
 #define CEILING_DIRECTORIES_ENVIRONMENT "GIT_CEILING_DIRECTORIES"
+#define NO_REPLACE_OBJECTS_ENVIRONMENT "GIT_NO_REPLACE_OBJECTS"
 #define GITATTRIBUTES_FILE ".gitattributes"
 #define INFOATTRIBUTES_FILE "info/attributes"
 #define ATTRIBUTE_MACRO_PREFIX "[attr]"

connect.c

@@ -609,6 +609,7 @@ struct child_process *git_connect(int fd[2], const char *url_orig,
 			GIT_WORK_TREE_ENVIRONMENT,
 			GRAFT_ENVIRONMENT,
 			INDEX_ENVIRONMENT,
+			NO_REPLACE_OBJECTS_ENVIRONMENT,
 			NULL
 		};
 		conn->env = env;

environment.c

@@ -84,6 +84,8 @@ static void setup_git_env(void)
 	git_graft_file = getenv(GRAFT_ENVIRONMENT);
 	if (!git_graft_file)
 		git_graft_file = git_pathdup("info/grafts");
+	if (getenv(NO_REPLACE_OBJECTS_ENVIRONMENT))
+		read_replace_refs = 0;
 }
 
 int is_bare_repository(void)

git.c

@@ -89,6 +89,9 @@ static int handle_options(const char ***argv, int *argc, int *envchanged)
 				*envchanged = 1;
 		} else if (!strcmp(cmd, "--no-replace-objects")) {
 			read_replace_refs = 0;
+			setenv(NO_REPLACE_OBJECTS_ENVIRONMENT, "1", 1);
+			if (envchanged)
+				*envchanged = 1;
 		} else if (!strcmp(cmd, "--git-dir")) {
 			if (*argc < 2) {
 				fprintf(stderr, "No directory given for --git-dir.\n" );

t/t6050-replace.sh

@@ -77,6 +77,11 @@ test_expect_success 'test --no-replace-objects option' '
      git --no-replace-objects show $HASH2 | grep "A U Thor"
 '
 
+test_expect_success 'test GIT_NO_REPLACE_OBJECTS env variable' '
+     GIT_NO_REPLACE_OBJECTS=1 git cat-file commit $HASH2 | grep "author A U Thor" &&
+     GIT_NO_REPLACE_OBJECTS=1 git show $HASH2 | grep "A U Thor"
+'
+
 cat >tag.sig <<EOF
 object $HASH2
 type commit
@@ -202,6 +207,18 @@ test_expect_success 'fetch branch with replacement' '
      cd ..
 '
 
+test_expect_success 'bisect and replacements' '
+     git bisect start $HASH7 $HASH1 &&
+     test "$S" = "$(git rev-parse --verify HEAD)" &&
+     git bisect reset &&
+     GIT_NO_REPLACE_OBJECTS=1 git bisect start $HASH7 $HASH1 &&
+     test "$HASH4" = "$(git rev-parse --verify HEAD)" &&
+     git bisect reset &&
+     git --no-replace-objects bisect start $HASH7 $HASH1 &&
+     test "$HASH4" = "$(git rev-parse --verify HEAD)" &&
+     git bisect reset
+'
+
 #
 #
 test_done