filter-repo: change --path-rename to work on matches instead of prefixes

Using an exact path (file or directory) for --path-rename instead of a
prefix removes an ugly caveat from the documentation, makes it operate
similarly to --path, and will make it easier to reuse common code when I
add the --paths-from-file option.  Switch over, and replace the
startswith() check by a call to filename_matches().

Signed-off-by: Elijah Newren <newren@gmail.com>

README.md

@@ -400,12 +400,11 @@ renamed to the same location), use --path-rename; for example, to rename
 both 'cmds/' and 'src/scripts/' to 'tools/':
 
 ```shell
-  git filter-repo --path-rename cmds/:tools/ --path-rename src/scripts/:tools/
+  git filter-repo --path-rename cmds:tools --path-rename src/scripts/:tools/
 ```
 
-It is preferable with `--path-rename` to using trailing slashes on
-directories since it matches on a prefix; without the trailing slash, a
-path named 'cmdstuff.txt' would be renamed to 'tools/tuff.txt'.
+As with `--path`, directories can be specified with or without a
+trailing slash for `--path-rename`.
 
 If you do a `--path-rename` to something that was already in use, it will
 be silently overwritten.  However, if you try to rename multiple files to

git-filter-repo

@@ -1886,9 +1886,15 @@ class FilteringOptions(object):
   class AppendFilter(argparse.Action):
     def __call__(self, parser, namespace, values, option_string=None):
       suffix = option_string[len('--path-'):] or 'match'
-      if suffix == 'rename':
+      if suffix.startswith('rename'):
         mod_type = 'rename'
-        match_type = 'prefix'
+        match_type = option_string[len('--path-rename-'):] or 'match'
+        values = values.split(b':', 1)
+        if values[0] and values[1] and not (
+           values[0].endswith(b'/') == values[1].endswith(b'/')):
+          raise SystemExit(_("Error: With --path-rename, if OLD_NAME and "
+                             "NEW_NAME are both non-empty and either ends "
+                             "with a slash then both must."))
       else:
         mod_type = 'filter'
         match_type = suffix
@@ -1982,12 +1988,12 @@ class FilteringOptions(object):
 
     rename = parser.add_argument_group(title=_("Renaming based on paths "
                                              "(see also --filename-callback)"))
-    rename.add_argument('--path-rename', '--path-rename-prefix',
+    rename.add_argument('--path-rename', '--path-rename-match',
         metavar='OLD_NAME:NEW_NAME', dest='path_changes', type=os.fsencode,
         action=FilteringOptions.AppendFilter,
-        help=_("Prefix to rename; if filename starts with OLD_NAME, "
-               "replace that with NEW_NAME.  Multiple --path-rename "
-               "options can be specified."))
+        help=_("Path to rename; if filename or directory matches OLD_NAME "
+               "rename to NEW_NAME.  Multiple --path-rename options can be "
+               "specified."))
 
     helpers = parser.add_argument_group(title=_("Path shortcuts"))
     helpers.add_argument('--subdirectory-filter', metavar='DIRECTORY',
@@ -2941,10 +2947,10 @@ class RepoFilter(object):
           if match_type == 'regex' and path_exp.search(pathname):
             wanted = True
         elif mod_type == 'rename':
-          old_exp, new_exp = path_exp.split(b':')
-          assert match_type in ('prefix',)
-          if match_type == 'prefix' and full_pathname.startswith(old_exp):
-            full_pathname = full_pathname.replace(old_exp, new_exp, 1)
+          match, repl = path_exp
+          assert match_type in ('match',)
+          if match_type == 'match' and filename_matches(match, full_pathname):
+            full_pathname = full_pathname.replace(match, repl, 1)
       return full_pathname if (wanted == filtering_is_inclusive) else None
 
     # Change the commit message according to callback

t/t9390-filter-repo.sh

@@ -858,7 +858,10 @@ test_expect_success 'other startup error cases and requests for help' '
 		test_i18ngrep ": --analyze is incompatible with --stdin" err &&
 
 		test_must_fail git filter-repo --path-rename foo:bar --use-base-name 2>err &&
-		test_i18ngrep ": --use-base-name and --path-rename are incompatible" err
+		test_i18ngrep ": --use-base-name and --path-rename are incompatible" err &&
+
+		test_must_fail git filter-repo --path-rename foo:bar/ 2>err &&
+		test_i18ngrep "either ends with a slash then both must." err
 	)
 '