[PATCH v6 06/11] clean: do not attempt to remove startup_info->original_cwd

["Elijah Newren via GitGitGadget" <gitgitgadget@xxxxxxxxx>]

From: Elijah Newren <newren@xxxxxxxxx>

Acked-by: Derrick Stolee <stolee@xxxxxxxxx>
Acked-by: Ævar Arnfjörð Bjarmason <avarab@xxxxxxxxx>
Signed-off-by: Elijah Newren <newren@xxxxxxxxx>
---
 builtin/clean.c      | 44 +++++++++++++++++++++++++++++++++++---------
 t/t2501-cwd-empty.sh |  5 +++--
 2 files changed, 38 insertions(+), 11 deletions(-)

diff --git a/builtin/clean.c b/builtin/clean.c
index 98a2860409b..3ff02bbbffe 100644
--- a/builtin/clean.c
+++ b/builtin/clean.c
@@ -36,6 +36,8 @@ static const char *msg_skip_git_dir = N_("Skipping repository %s\n");
 static const char *msg_would_skip_git_dir = N_("Would skip repository %s\n");
 static const char *msg_warn_remove_failed = N_("failed to remove %s");
 static const char *msg_warn_lstat_failed = N_("could not lstat %s\n");
+static const char *msg_skip_cwd = N_("Refusing to remove current working directory\n");
+static const char *msg_would_skip_cwd = N_("Would refuse to remove current working directory\n");
 
 enum color_clean {
 	CLEAN_COLOR_RESET = 0,
@@ -153,6 +155,8 @@ static int remove_dirs(struct strbuf *path, const char *prefix, int force_flag,
 {
 	DIR *dir;
 	struct strbuf quoted = STRBUF_INIT;
+	struct strbuf realpath = STRBUF_INIT;
+	struct strbuf real_ocwd = STRBUF_INIT;
 	struct dirent *e;
 	int res = 0, ret = 0, gone = 1, original_len = path->len, len;
 	struct string_list dels = STRING_LIST_INIT_DUP;
@@ -231,16 +235,36 @@ static int remove_dirs(struct strbuf *path, const char *prefix, int force_flag,
 	strbuf_setlen(path, original_len);
 
 	if (*dir_gone) {
-		res = dry_run ? 0 : rmdir(path->buf);
-		if (!res)
-			*dir_gone = 1;
-		else {
-			int saved_errno = errno;
-			quote_path(path->buf, prefix, &quoted, 0);
-			errno = saved_errno;
-			warning_errno(_(msg_warn_remove_failed), quoted.buf);
+		/*
+		 * Normalize path components in path->buf, e.g. change '\' to
+		 * '/' on Windows.
+		 */
+		strbuf_realpath(&realpath, path->buf, 1);
+
+		/*
+		 * path and realpath are absolute; for comparison, we would
+		 * like to transform startup_info->original_cwd to an absolute
+		 * path too.
+		 */
+		 if (startup_info->original_cwd)
+			 strbuf_realpath(&real_ocwd,
+					 startup_info->original_cwd, 1);
+
+		if (!strbuf_cmp(&realpath, &real_ocwd)) {
+			printf("%s", dry_run ? _(msg_would_skip_cwd) : _(msg_skip_cwd));
 			*dir_gone = 0;
-			ret = 1;
+		} else {
+			res = dry_run ? 0 : rmdir(path->buf);
+			if (!res)
+				*dir_gone = 1;
+			else {
+				int saved_errno = errno;
+				quote_path(path->buf, prefix, &quoted, 0);
+				errno = saved_errno;
+				warning_errno(_(msg_warn_remove_failed), quoted.buf);
+				*dir_gone = 0;
+				ret = 1;
+			}
 		}
 	}
 
@@ -250,6 +274,8 @@ static int remove_dirs(struct strbuf *path, const char *prefix, int force_flag,
 			printf(dry_run ?  _(msg_would_remove) : _(msg_remove), dels.items[i].string);
 	}
 out:
+	strbuf_release(&realpath);
+	strbuf_release(&real_ocwd);
 	strbuf_release(&quoted);
 	string_list_clear(&dels, 0);
 	return ret;
diff --git a/t/t2501-cwd-empty.sh b/t/t2501-cwd-empty.sh
index e4502d24d57..b1182390ba3 100755
--- a/t/t2501-cwd-empty.sh
+++ b/t/t2501-cwd-empty.sh
@@ -230,8 +230,9 @@ test_incidental_untracked_dir_removal () {
 }
 
 test_expect_success 'clean does not remove cwd incidentally' '
-	test_incidental_untracked_dir_removal failure \
-		git -C .. clean -fd -e warnings . >warnings
+	test_incidental_untracked_dir_removal success \
+		git -C .. clean -fd -e warnings . >warnings &&
+	grep "Refusing to remove current working directory" warnings
 '
 
 test_expect_success 'stash does not remove cwd incidentally' '
-- 
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