[Bug-tar] The --exclude-ignore option acts recursively, while it shouldn't

[Kirill Pushkaryov]

Hello!

I've found that patterns from a file specified via the --exclude-ignore option are excluded from subdirectories too, which contradicts the manual. The problem was encountered in tar 1.28 and confirmed in the latest tar from the git.savannah.gnu.org/tar.git.

The manual says (6.4):

"`--exclude-ignore=file'

Before dumping a directory, tar checks if it contains file. If so, exclusion patterns are read from this file. The patterns affect only the directory itself."

How to reproduce:

mkdir test test/a
touch test/b test/a/b
echo b > test/.ign
tar -cvf test.tar --exclude-ignore=.ign test

Current result:

test/
test/.ign
test/a/

Expected result: test/a/b must not be excluded.

I'm not familiar with the source code, but after quick debugging I suspect a bug in info_attach_exclist() (exclist.c:117 from the git HEAD (1d2674b)):

      ent = xmalloc (sizeof (*ent));
      ent->excluded = ex;
      ent->flags = file->flags == EXCL_DEFAULT
                   ? file->flags : vcsfile->flags;
      ent->prev = tail;
      ent->next = NULL;

It looks like file->flags are propagated to ent->flags only when they're equal to EXCL_DEFAULT (0x00), so EXCL_NON_RECURSIVE (0x02) pertaining to --exclude-ignore is dropped, which prevents the condition in excluded_name() (exclist.c:172) from skipping non-recursive entries from distant ancestors.

--

WBR, Kirill Pushkaryov.