Merge branch 'ab/conditional-config-with-symlinks'

The recently introduced "[includeIf "gitdir:$dir"] path=..."
mechansim has further been taught to take symlinks into account.
The directory "$dir" specified in "gitdir:$dir" may be a symlink to
a real location, not something that $(getcwd) may return.  In such
a case, a realpath of "$dir" is compared with the real path of the
current repository to determine if the contents from the named path
should be included.

* ab/conditional-config-with-symlinks:
  config: match both symlink & realpath versions in IncludeIf.gitdir:*

Documentation/config.txt

@@ -145,6 +145,16 @@ A few more notes on matching via `gitdir` and `gitdir/i`:
 
  * Symlinks in `$GIT_DIR` are not resolved before matching.
 
+ * Both the symlink & realpath versions of paths will be matched
+   outside of `$GIT_DIR`. E.g. if ~/git is a symlink to
+   /mnt/storage/git, both `gitdir:~/git` and `gitdir:/mnt/storage/git`
+   will match.
++
+This was not the case in the initial release of this feature in
+v2.13.0, which only matched the realpath version. Configuration that
+wants to be compatible with the initial release of this feature needs
+to either specify only the realpath version, or both versions.
+
  * Note that "../" is not special and will match literally, which is
    unlikely what you want.
 

config.c

@@ -214,6 +214,7 @@ static int include_by_gitdir(const struct config_options *opts,
 	struct strbuf pattern = STRBUF_INIT;
 	int ret = 0, prefix;
 	const char *git_dir;
+	int already_tried_absolute = 0;
 
 	if (opts->git_dir)
 		git_dir = opts->git_dir;
@@ -226,6 +227,7 @@ static int include_by_gitdir(const struct config_options *opts,
 	strbuf_add(&pattern, cond, cond_len);
 	prefix = prepare_include_condition_pattern(&pattern);
 
+again:
 	if (prefix < 0)
 		goto done;
 
@@ -245,6 +247,20 @@ static int include_by_gitdir(const struct config_options *opts,
 	ret = !wildmatch(pattern.buf + prefix, text.buf + prefix,
 			 icase ? WM_CASEFOLD : 0, NULL);
 
+	if (!ret && !already_tried_absolute) {
+		/*
+		 * We've tried e.g. matching gitdir:~/work, but if
+		 * ~/work is a symlink to /mnt/storage/work
+		 * strbuf_realpath() will expand it, so the rule won't
+		 * match. Let's match against a
+		 * strbuf_add_absolute_path() version of the path,
+		 * which'll do the right thing
+		 */
+		strbuf_reset(&text);
+		strbuf_add_absolute_path(&text, git_dir);
+		already_tried_absolute = 1;
+		goto again;
+	}
 done:
 	strbuf_release(&pattern);
 	strbuf_release(&text);

t/t1305-config-include.sh

@@ -273,6 +273,29 @@ test_expect_success SYMLINKS 'conditional include, relative path with symlinks'
 	)
 '
 
+test_expect_success SYMLINKS 'conditional include, gitdir matching symlink' '
+	ln -s foo bar &&
+	(
+		cd bar &&
+		echo "[includeIf \"gitdir:bar/\"]path=bar7" >>.git/config &&
+		echo "[test]seven=7" >.git/bar7 &&
+		echo 7 >expect &&
+		git config test.seven >actual &&
+		test_cmp expect actual
+	)
+'
+
+test_expect_success SYMLINKS 'conditional include, gitdir matching symlink, icase' '
+	(
+		cd bar &&
+		echo "[includeIf \"gitdir/i:BAR/\"]path=bar8" >>.git/config &&
+		echo "[test]eight=8" >.git/bar8 &&
+		echo 8 >expect &&
+		git config test.eight >actual &&
+		test_cmp expect actual
+	)
+'
+
 test_expect_success 'include cycles are detected' '
 	cat >.gitconfig <<-\EOF &&
 	[test]value = gitconfig