[PATCH v2 9/9] dir: new flag to remove_dir_recurse() to spare the original_cwd

From: Elijah Newren via GitGitGadget <gitgitgadget@gmail.com>
Date: Nov 25, 2021, 08:39 UTC
Message-ID: <adaad7aeaac20357f1b83d21085257b8b8fe4591.1637829556.git.gitgitgadget@gmail.com>
In-Reply-To: <pull.1140.v2.git.git.1637829556.gitgitgadget@gmail.com>

From: Elijah Newren <newren@gmail.com>

remove_dir_recurse(), and its non-static wrapper called remove_dir_recursively(), both take flags for modifying its behavior. As with the previous commits, we would generally like to protect the original_cwd, but we want to forced user commands (e.g. 'git rm -rf ...') or other special cases to remove it. Add a flag for this purpose. After reading through every caller of remove_dir_recursively() in the current codebase, there was only one that should be adjusted and that one only in a very unusual circumstance. Add a pair of new testcases to highlight that very specific case involving submodules && --git-dir && --work-tree.

Signed-off-by: Elijah Newren <newren@gmail.com>
---
 builtin/rm.c         |  3 ++-
 dir.c                | 12 +++++++++---
 dir.h                |  3 +++
 t/t2501-cwd-empty.sh | 42 ++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 56 insertions(+), 4 deletions(-)

diff --git a/builtin/rm.c b/builtin/rm.c
index 3d0967cdc11..b4132e5d8ee 100644
--- a/builtin/rm.c
+++ b/builtin/rm.c
@@ -399,12 +399,13 @@ int cmd_rm(int argc, const char **argv, const char *prefix)
 	if (!index_only) {
 		int removed = 0, gitmodules_modified = 0;
 		struct strbuf buf = STRBUF_INIT;
+		int flag = force ? REMOVE_DIR_PURGE_ORIGINAL_CWD : 0;
 		for (i = 0; i < list.nr; i++) {
 			const char *path = list.entry[i].name;
 			if (list.entry[i].is_submodule) {
 				strbuf_reset(&buf);
 				strbuf_addstr(&buf, path);
-				if (remove_dir_recursively(&buf, 0))
+				if (remove_dir_recursively(&buf, flag))
 					die(_("could not remove '%s'"), path);
 
 				removed = 1;
diff --git a/dir.c b/dir.c
index 97d6b71c872..52064345a6b 100644
--- a/dir.c
+++ b/dir.c
@@ -3204,6 +3204,7 @@ static int remove_dir_recurse(struct strbuf *path, int flag, int *kept_up)
 	int ret = 0, original_len = path->len, len, kept_down = 0;
 	int only_empty = (flag & REMOVE_DIR_EMPTY_ONLY);
 	int keep_toplevel = (flag & REMOVE_DIR_KEEP_TOPLEVEL);
+	int purge_original_cwd = (flag & REMOVE_DIR_PURGE_ORIGINAL_CWD);
 	struct object_id submodule_head;
 
 	if ((flag & REMOVE_DIR_KEEP_NESTED_GIT) &&
@@ -3259,9 +3260,14 @@ static int remove_dir_recurse(struct strbuf *path, int flag, int *kept_up)
 	closedir(dir);
 
 	strbuf_setlen(path, original_len);
-	if (!ret && !keep_toplevel && !kept_down)
-		ret = (!rmdir(path->buf) || errno == ENOENT) ? 0 : -1;
-	else if (kept_up)
+	if (!ret && !keep_toplevel && !kept_down) {
+		if (!purge_original_cwd &&
+		    startup_info->original_cwd &&
+		    !strcmp(startup_info->original_cwd, path->buf))
+			ret = -1; /* Do not remove current working directory */
+		else
+			ret = (!rmdir(path->buf) || errno == ENOENT) ? 0 : -1;
+	} else if (kept_up)
 		/*
 		 * report the uplevel that it is not an error that we
 		 * did not rmdir() our directory.
diff --git a/dir.h b/dir.h
index d6a5d03bec2..8e02dfb505d 100644
--- a/dir.h
+++ b/dir.h
@@ -495,6 +495,9 @@ int get_sparse_checkout_patterns(struct pattern_list *pl);
 /* Remove the contents of path, but leave path itself. */
 #define REMOVE_DIR_KEEP_TOPLEVEL 04
 
+/* Remove the_original_cwd too */
+#define REMOVE_DIR_PURGE_ORIGINAL_CWD 0x08
+
 /*
  * Remove path and its contents, recursively. flags is a combination
  * of the above REMOVE_DIR_* constants. Return 0 on success.
diff --git a/t/t2501-cwd-empty.sh b/t/t2501-cwd-empty.sh
index 4362e7b15e5..8da3fb1f5d3 100755
--- a/t/t2501-cwd-empty.sh
+++ b/t/t2501-cwd-empty.sh
@@ -252,4 +252,46 @@ test_expect_success 'stash does not remove cwd incidentally' '
 	test_path_is_dir untracked
 '
 
+test_expect_success 'rm -r leaves submodule if cwd inside' '
+	test_when_finished "git reset --hard HEAD~1" &&
+	test_when_finished "rm -rf .git/modules/my_submodule" &&
+
+	git checkout foo/bar/baz &&
+
+	git init my_submodule &&
+	touch my_submodule/file &&
+	git -C my_submodule add file &&
+	git -C my_submodule commit -m "initial commit" &&
+	git submodule add ./my_submodule &&
+	git commit -m "Add the submodule" &&
+
+	(
+		cd my_submodule &&
+		test_must_fail git --git-dir=../.git --work-tree=.. rm -r ../my_submodule/
+	) &&
+
+	test_path_is_dir my_submodule
+'
+
+test_expect_success 'rm -rf removes submodule even if cwd inside' '
+	test_when_finished "git reset --hard HEAD~1" &&
+	test_when_finished "rm -rf .git/modules/my_submodule" &&
+
+	git checkout foo/bar/baz &&
+
+	git init my_submodule &&
+	touch my_submodule/file &&
+	git -C my_submodule add file &&
+	git -C my_submodule commit -m "initial commit" &&
+	git submodule add ./my_submodule &&
+	git commit -m "Add the submodule" &&
+
+	(
+		cd my_submodule &&
+		git --git-dir=../.git --work-tree=.. rm -rf ../my_submodule/
+	) &&
+
+	test_path_is_missing my_submodule
+'
+
 test_done

-- 
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