dir, clean: avoid disallowed behavior

dir.h documented quite clearly that DIR_SHOW_IGNORED and DIR_SHOW_IGNORED_TOO are mutually exclusive, with a big comment to this effect by the definition of both enum values. However, a command like git clean -fx $DIR would set both values for dir.flags. I _think_ it happened to work because: * As dir.h points out, DIR_KEEP_UNTRACKED_CONTENTS only takes effect if DIR_SHOW_IGNORED_TOO is set. * As coded, I believe DIR_SHOW_IGNORED would just happen to take precedence over DIR_SHOW_IGNORED_TOO in the code as currently constructed. Which is a long way of saying "we just got lucky". Fix clean.c to avoid setting these mutually exclusive values at the same time, and add a check to dir.c that will throw a BUG() to prevent anyone else from making this mistake. Signed-off-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Elijah Newren committed Jun 11, 2020 at 06:59 UTC 351ea1c3cbf416b40cb999ea7426da633fa64918

2 files changed +5 -1

builtin/clean.c

+1 -1

@@ -954,7 +954,7 @@ int cmd_clean(int argc, const char **argv, const char *prefix)

954 remove_directories = 1;

955 }

956

957 - if (remove_directories)

957 + if (remove_directories && !ignored_only)

958 dir.flags |= DIR_SHOW_IGNORED_TOO | DIR_KEEP_UNTRACKED_CONTENTS;

959

960 if (read_cache() < 0)

dir.c

@@ -193,6 +193,10 @@ int fill_directory(struct dir_struct *dir,

193 const char *prefix;

194 size_t prefix_len;

195

196 + unsigned exclusive_flags = DIR_SHOW_IGNORED | DIR_SHOW_IGNORED_TOO;

197 + if ((dir->flags & exclusive_flags) == exclusive_flags)

198 + BUG("DIR_SHOW_IGNORED and DIR_SHOW_IGNORED_TOO are exclusive");

199 +

200 /*

201 * Calculate common prefix for the pathspec, and

202 * use that to optimize the directory walk