Fix handling of negated and rooted entries in .gitignore files.

* src/exclist.c (struct vcs_ignore_file): New field: matchfn.
(struct exclist): New field: vcs.
(info_attach_exclist): Initialize vcs.
(excluded_name): Rewrite using excluded_file_name_status from gnulib.
(git_addfn): Special handling for entries starting with '!' and '/'.
(vcs_ignore_files): Initialize matchfn member in the ".gitignore"
entry.

* tests/exclude23.at: New test.
* tests/Makefile.am: Add new test.
* tests/testsuite.at: Include new test.

src/exclist.c

@@ -33,6 +33,7 @@ struct vcs_ignore_file
   int flags;
   add_fn addfn;
   void *(*initfn) (void *);
+  int (*matchfn) (struct exclude *, char const *);
   void *data;
 };
 
@@ -69,6 +70,7 @@ struct exclist
   char *prefix;
   size_t prefix_len;
   struct exclude *excluded;
+  struct vcs_ignore_file *vcs;
 };
 
 void
@@ -115,6 +117,7 @@ info_attach_exclist (struct tar_stat_info *dir)
 	  ent->flags = file->flags;
 	  ent->prefix_len = strlen (dir->orig_file_name);
 	  ent->prefix = xstrdup (dir->orig_file_name);
+	  ent->vcs = vcsfile;
 	  ent->prev = tail;
 	  ent->next = NULL;
 
@@ -152,7 +155,7 @@ excluded_name (char const *name, struct tar_stat_info *st)
 {
   struct exclist *ep;
   char *bname = NULL;
-  bool result;
+  int result;
   int nr = 0;
 
   name += FILE_SYSTEM_PREFIX_LEN (name);
@@ -164,7 +167,7 @@ excluded_name (char const *name, struct tar_stat_info *st)
   if (!st)
     return false;
 
-  for (result = false; st && !result; st = st->parent, nr = EXCL_NON_RECURSIVE)
+  for (result = 0; st; st = st->parent, nr = EXCL_NON_RECURSIVE)
     {
       for (ep = st->exclude_list; ep; ep = ep->next)
 	{
@@ -173,27 +176,37 @@ excluded_name (char const *name, struct tar_stat_info *st)
 	  if (ep->flags & nr)
 	    continue;
 
-	  if ((result = excluded_file_name (ep->excluded, name)))
-	    break;
+	  result = excluded_file_name_status (ep->excluded, name);
+	  if (result & EXCLUDED_MATCHED)
+	    goto end;
 
 	  if (ep->prefix_len && strlen (name) > ep->prefix_len &&
 	      memcmp (name, ep->prefix, ep->prefix_len) == 0)
 	    rname = name + ep->prefix_len;
-          else
+	  else
 	    rname = name + dotslashlen (name);
-	  if ((result = excluded_file_name (ep->excluded, rname)))
-	    break;
+	  result = excluded_file_name_status (ep->excluded, rname);
+	  if (result & EXCLUDED_MATCHED)
+	    goto end;
+
+	  if (ep->vcs->matchfn)
+	    {
+	      result = ep->vcs->matchfn (ep->excluded, rname);
+	      if (result & EXCLUDED_MATCHED)
+		goto end;
+	    }
 
 	  if (!bname)
 	    bname = base_name (name);
-	  if ((result = excluded_file_name (ep->excluded, bname)))
-	    break;
+	  result = excluded_file_name_status (ep->excluded, bname);
+	  if (result & EXCLUDED_MATCHED)
+	    goto end;
 	}
     }
-
+ end:
   free (bname);
 
-  return result;
+  return (result & EXCLUDED_MATCHED) ? (result & EXCLUDED_EXCLUDED) : 0;
 }
 
 static void
@@ -220,11 +233,32 @@ git_addfn (struct exclude *ex, char const *pattern, int options,
     ++pattern;
   if (*pattern == 0 || *pattern == '#')
     return;
-  if (*pattern == '\\' && pattern[1] == '#')
+  if (*pattern == '\\' && (pattern[1] == '#' || pattern[1] == '!'))
     ++pattern;
+  else if (*pattern == '!')
+    {
+      ++pattern;
+      options |= EXCLUDE_INCLUDE;
+    }
+  else if (*pattern == '/')
+    {
+      options |= EXCLUDE_ANCHORED;
+    }
   add_exclude (ex, pattern, options);
 }
 
+static int
+git_matchfn (struct exclude *ex, char const *name)
+{
+  int rc;
+  char *rname = xmalloc (strlen (name) + 2);
+  rname[0] = '/';
+  strcpy (rname + 1, name);
+  rc = excluded_file_name_status (ex, rname);
+  free (rname);
+  return rc;
+}
+
 static void
 bzr_addfn (struct exclude *ex, char const *pattern, int options,
 	   void *UNNAMED (data))
@@ -303,18 +337,35 @@ hg_addfn (struct exclude *ex, char const *pattern, int options, void *data)
 }
 
 static struct vcs_ignore_file vcs_ignore_files[] = {
-  { ".cvsignore", EXCL_NON_RECURSIVE, cvs_addfn, NULL, NULL },
-  { ".gitignore", 0, git_addfn, NULL, NULL },
-  { ".bzrignore", 0, bzr_addfn, NULL, NULL },
-  { ".hgignore",  0, hg_addfn, hg_initfn, NULL },
-  { NULL, 0, git_addfn, NULL, NULL }
+  {
+    .filename = ".cvsignore",
+    .flags = EXCL_NON_RECURSIVE,
+    .addfn = cvs_addfn
+  },
+  {
+    .filename = ".gitignore",
+    .addfn = git_addfn,
+    .matchfn = git_matchfn
+  },
+  {
+    .filename = ".bzrignore",
+    .addfn = bzr_addfn
+  },
+  {
+    .filename = ".hgignore",
+    .addfn = hg_addfn,
+    .initfn = hg_initfn
+  },
+  {
+    .addfn = git_addfn
+  }
 };
 
 static struct vcs_ignore_file *
 get_vcs_ignore_file (const char *name)
 {
-  struct vcs_ignore_file *p;
-
+  struct vcs_ignore_file *p
+;
   for (p = vcs_ignore_files; p->filename; p++)
     if (streq (p->filename, name))
       break;

tests/Makefile.am

@@ -112,6 +112,7 @@ TESTSUITE_AT = \
  exclude20.at\
  exclude21.at\
  exclude22.at\
+ exclude23.at\
  extrac01.at\
  extrac02.at\
  extrac03.at\

tests/exclude22.at

@@ -21,6 +21,7 @@
 AT_SETUP([--exclude-ignore-recursive with transforms])
 AT_KEYWORDS([exclude exclude-ignore-recursive extract exclude22])
 AT_TAR_CHECK([
+AT_SORT_PREREQ
 mkdir dir dir/subdir
 touch dir/file1 dir/file.ext dir/subdir/file2.foo dir/subdir/file3 \
       dir/subdir/file4.txt dir/subdir/file5.ext

tests/exclude23.at

@@ -0,0 +1,55 @@
+# Process this file with autom4te to create testsuite. -*- Autotest -*-
+
+# Test suite for GNU tar.
+# Copyright 2026 Free Software Foundation, Inc.
+
+# This file is part of GNU tar.
+
+# GNU tar is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+
+# GNU tar is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+AT_SETUP([gitignore excludes])
+AT_KEYWORDS([exclude gitignore extract exclude23])
+AT_TAR_CHECK([
+AT_SORT_PREREQ
+# Test whether negations (!) and rooted patterns (/) work in
+# .gitignore files.
+mkdir dir dir/subdir
+touch dir/subdir/some.1 dir/subdir/any.1 dir/subdir/bar dir/subdir/FILE
+cat > dir/subdir/.gitignore <<EOT
+!any.1
+EOT
+touch dir/foo.1 dir/file.1 dir/file.2 dir/file.3 dir/file.4 dir/FILE
+cat > dir/.gitignore <<EOT
+*.1
+*.2
+!foo.1
+*.3
+/FILE
+/subdir/b?r
+EOT
+set -e
+tar --exclude-ignore-recursive=.gitignore -cf dir.tar dir
+tar tf dir.tar | sort
+],
+[0],
+[dir/
+dir/.gitignore
+dir/file.4
+dir/foo.1
+dir/subdir/
+dir/subdir/.gitignore
+dir/subdir/FILE
+dir/subdir/any.1
+])
+AT_CLEANUP

tests/testsuite.at

@@ -319,6 +319,7 @@ m4_include([exclude19.at])
 m4_include([exclude20.at])
 m4_include([exclude21.at])
 m4_include([exclude22.at])
+m4_include([exclude23.at])
 
 AT_BANNER([Deletions])
 m4_include([delete01.at])