[PATCH v5 6/6] clean: teach clean -d to preserve ignored paths

From: Samuel Lijin <sxlijin@gmail.com>
Date: May 23, 2017, 09:18 UTC
Message-ID: <20170523091829.1746-7-sxlijin@gmail.com>
In-Reply-To: <20170523091829.1746-1-sxlijin@gmail.com>

There is an implicit assumption that a directory containing only untracked and ignored paths should itself be considered untracked. This makes sense in use cases where we're asking if a directory should be added to the git database, but not when we're asking if a directory can be safely removed from the working tree; as a result, clean -d would assume that an "untracked" directory containing ignored paths could be deleted, even though doing so would also remove the ignored paths.

To get around this, we teach clean -d to collect ignored paths and skip an untracked directory if it contained an ignored path, instead just removing the untracked contents thereof. To achieve this, cmd_clean() has to collect all untracked contents of untracked directories, in addition to all ignored paths, to determine which untracked dirs must be skipped (because they contain ignored paths) and which ones should *not* be skipped.

For this purpose, correct_untracked_entries() is introduced to prune a given dir_struct of untracked entries containing ignored paths and those untracked entries encompassed by the untracked entries which are not pruned away.

This also fixes the known breakage in t7300, since clean -d now skips untracked directories containing ignored paths.

Signed-off-by: Samuel Lijin <sxlijin@gmail.com>
---
 builtin/clean.c  | 31 +++++++++++++++++++++++++++++++
 t/t7300-clean.sh |  2 +-
 2 files changed, 32 insertions(+), 1 deletion(-)

diff --git a/builtin/clean.c b/builtin/clean.c
index d861f836a..45dbdcd18 100644
--- a/builtin/clean.c
+++ b/builtin/clean.c
@@ -857,6 +857,36 @@ static void interactive_main_loop(void)
 	}
 }
 
+static void correct_untracked_entries(struct dir_struct *dir)
+{
+	int src, dst, ign;
+
+	for (src = dst = ign = 0; src < dir->nr; src++) {
+		/* skip paths in ignored[] that cannot be inside entries[src] */
+		while (ign < dir->ignored_nr &&
+		       0 <= cmp_dir_entry(&dir->entries[src], &dir->ignored[ign]))
+			ign++;
+
+		if (ign < dir->ignored_nr &&
+		    check_dir_entry_contains(dir->entries[src], dir->ignored[ign])) {
+			/* entries[src] contains an ignored path, so we drop it */
+			free(dir->entries[src]);
+		} else {
+			/* entries[src] does not contain an ignored path, so we keep it */
+			dir->entries[dst++] = dir->entries[src++];
+
+			/* then discard paths in entries[] contained inside entries[src] */
+			while (src < dir->nr &&
+			       check_dir_entry_contains(ent, dir->entries[src]))
+				free(dir->entries[src++]);
+
+			/* compensate for the outer loop's loop control */
+			src--;
+		}
+	}
+	dir->nr = dst;
+}
+
 int cmd_clean(int argc, const char **argv, const char *prefix)
 {
 	int i, res;
@@ -931,6 +961,7 @@ int cmd_clean(int argc, const char **argv, const char *prefix)
 		       prefix, argv);
 
 	fill_directory(&dir, &pathspec);
+	correct_untracked_entries(&dir);
 
 	for (i = 0; i < dir.nr; i++) {
 		struct dir_entry *ent = dir.entries[i];
diff --git a/t/t7300-clean.sh b/t/t7300-clean.sh
index 3a2d709c2..7b36954d6 100755
--- a/t/t7300-clean.sh
+++ b/t/t7300-clean.sh
@@ -653,7 +653,7 @@ test_expect_success 'git clean -d respects pathspecs (pathspec is prefix of dir)
 	test_path_is_dir foobar
 '
 
-test_expect_failure 'git clean -d skips untracked dirs containing ignored files' '
+test_expect_success 'git clean -d skips untracked dirs containing ignored files' '
 	echo /foo/bar >.gitignore &&
 	echo ignoreme >>.gitignore &&
 	rm -rf foo &&

-- 
2.13.0