Merge branch 'ed/simplify-setup-git-dir'

Code simplification.

* ed/simplify-setup-git-dir:
  Simplify handling of setup_git_directory_gently() failure cases.

setup.c

@@ -831,16 +831,6 @@ static const char *setup_bare_git_dir(struct strbuf *cwd, int offset,
 	return NULL;
 }
 
-static const char *setup_nongit(const char *cwd, int *nongit_ok)
-{
-	if (!nongit_ok)
-		die(_("not a git repository (or any of the parent directories): %s"), DEFAULT_GIT_DIR_ENVIRONMENT);
-	if (chdir(cwd))
-		die_errno(_("cannot come back to cwd"));
-	*nongit_ok = 1;
-	return NULL;
-}
-
 static dev_t get_device_or_die(const char *path, const char *prefix, int prefix_len)
 {
 	struct stat buf;
@@ -1054,7 +1044,7 @@ const char *setup_git_directory_gently(int *nongit_ok)
 {
 	static struct strbuf cwd = STRBUF_INIT;
 	struct strbuf dir = STRBUF_INIT, gitdir = STRBUF_INIT;
-	const char *prefix;
+	const char *prefix = NULL;
 	struct repository_format repo_fmt;
 
 	/*
@@ -1079,9 +1069,6 @@ const char *setup_git_directory_gently(int *nongit_ok)
 	strbuf_addbuf(&dir, &cwd);
 
 	switch (setup_git_directory_gently_1(&dir, &gitdir, 1)) {
-	case GIT_DIR_NONE:
-		prefix = NULL;
-		break;
 	case GIT_DIR_EXPLICIT:
 		prefix = setup_explicit_git_dir(gitdir.buf, &cwd, &repo_fmt, nongit_ok);
 		break;
@@ -1097,29 +1084,51 @@ const char *setup_git_directory_gently(int *nongit_ok)
 		prefix = setup_bare_git_dir(&cwd, dir.len, &repo_fmt, nongit_ok);
 		break;
 	case GIT_DIR_HIT_CEILING:
-		prefix = setup_nongit(cwd.buf, nongit_ok);
+		if (!nongit_ok)
+			die(_("not a git repository (or any of the parent directories): %s"),
+			    DEFAULT_GIT_DIR_ENVIRONMENT);
+		*nongit_ok = 1;
 		break;
 	case GIT_DIR_HIT_MOUNT_POINT:
-		if (nongit_ok) {
-			*nongit_ok = 1;
-			strbuf_release(&cwd);
-			strbuf_release(&dir);
-			return NULL;
-		}
-		die(_("not a git repository (or any parent up to mount point %s)\n"
-		      "Stopping at filesystem boundary (GIT_DISCOVERY_ACROSS_FILESYSTEM not set)."),
-		    dir.buf);
+		if (!nongit_ok)
+			die(_("not a git repository (or any parent up to mount point %s)\n"
+			      "Stopping at filesystem boundary (GIT_DISCOVERY_ACROSS_FILESYSTEM not set)."),
+			    dir.buf);
+		*nongit_ok = 1;
+		break;
+	case GIT_DIR_NONE:
+		/*
+		 * As a safeguard against setup_git_directory_gently_1 returning
+		 * this value, fallthrough to BUG. Otherwise it is possible to
+		 * set startup_info->have_repository to 1 when we did nothing to
+		 * find a repository.
+		 */
 	default:
 		BUG("unhandled setup_git_directory_1() result");
 	}
 
-	if (prefix)
-		setenv(GIT_PREFIX_ENVIRONMENT, prefix, 1);
-	else
+	/*
+	 * At this point, nongit_ok is stable. If it is non-NULL and points
+	 * to a non-zero value, then this means that we haven't found a
+	 * repository and that the caller expects startup_info to reflect
+	 * this.
+	 *
+	 * Regardless of the state of nongit_ok, startup_info->prefix and
+	 * the GIT_PREFIX environment variable must always match. For details
+	 * see Documentation/config/alias.txt.
+	 */
+	if (nongit_ok && *nongit_ok) {
+		startup_info->have_repository = 0;
+		startup_info->prefix = NULL;
 		setenv(GIT_PREFIX_ENVIRONMENT, "", 1);
-
-	startup_info->have_repository = !nongit_ok || !*nongit_ok;
-	startup_info->prefix = prefix;
+	} else {
+		startup_info->have_repository = 1;
+		startup_info->prefix = prefix;
+		if (prefix)
+			setenv(GIT_PREFIX_ENVIRONMENT, prefix, 1);
+		else
+			setenv(GIT_PREFIX_ENVIRONMENT, "", 1);
+	}
 
 	/*
 	 * Not all paths through the setup code will call 'set_git_dir()' (which
@@ -1132,7 +1141,10 @@ const char *setup_git_directory_gently(int *nongit_ok)
 	 * the user has set GIT_DIR.  It may be beneficial to disallow bogus
 	 * GIT_DIR values at some point in the future.
 	 */
-	if (startup_info->have_repository || getenv(GIT_DIR_ENVIRONMENT)) {
+	if (/* GIT_DIR_EXPLICIT, GIT_DIR_DISCOVERED, GIT_DIR_BARE */
+	    startup_info->have_repository ||
+	    /* GIT_DIR_EXPLICIT */
+	    getenv(GIT_DIR_ENVIRONMENT)) {
 		if (!the_repository->gitdir) {
 			const char *gitdir = getenv(GIT_DIR_ENVIRONMENT);
 			if (!gitdir)