[PATCH] diff: differentiate error handling in parse_color_moved_ws

[Stefan Beller <sbeller@google.com>]

As we check command line options more strictly and allow configuration
variables to be parsed more leniently, we need take different actions
based on whether an unknown value is given on the command line or in the
config.

Move the die() call out of parse_color_moved_ws into the parsing
of command line options. As the function returns a bit field, change
its signature to return an unsigned instead of an int; add a new bit
to signal errors. Once the error is signaled, we discard the other
bits, such that it doesn't matter if the error bit overlaps with any
other bit.

Signed-off-by: Stefan Beller <sbeller@google.com>
---

This is a fresh attempt to cleanup the sloppy part that was mentioned
in https://public-inbox.org/git/xmqqa7nkf6o4.fsf@gitster-ct.c.googlers.com/

Another thing to follow up is to have color-moved-ws imply color-moved.

Thanks,
Stefan


 diff.c | 21 ++++++++++++++-------
 diff.h |  3 ++-
 2 files changed, 16 insertions(+), 8 deletions(-)

diff --git a/diff.c b/diff.c
index 8647db3d30..f21f8b0332 100644
--- a/diff.c
+++ b/diff.c
@@ -291,7 +291,7 @@ static int parse_color_moved(const char *arg)
 		return error(_("color moved setting must be one of 'no', 'default', 'blocks', 'zebra', 'dimmed-zebra', 'plain'"));
 }
 
-static int parse_color_moved_ws(const char *arg)
+static unsigned parse_color_moved_ws(const char *arg)
 {
 	int ret = 0;
 	struct string_list l = STRING_LIST_INIT_DUP;
@@ -312,15 +312,19 @@ static int parse_color_moved_ws(const char *arg)
 			ret |= XDF_IGNORE_WHITESPACE;
 		else if (!strcmp(sb.buf, "allow-indentation-change"))
 			ret |= COLOR_MOVED_WS_ALLOW_INDENTATION_CHANGE;
-		else
+		else {
+			ret |= COLOR_MOVED_WS_ERROR;
 			error(_("ignoring unknown color-moved-ws mode '%s'"), sb.buf);
+		}
 
 		strbuf_release(&sb);
 	}
 
 	if ((ret & COLOR_MOVED_WS_ALLOW_INDENTATION_CHANGE) &&
-	    (ret & XDF_WHITESPACE_FLAGS))
-		die(_("color-moved-ws: allow-indentation-change cannot be combined with other white space modes"));
+	    (ret & XDF_WHITESPACE_FLAGS)) {
+		error(_("color-moved-ws: allow-indentation-change cannot be combined with other white space modes"));
+		ret |= COLOR_MOVED_WS_ERROR;
+	}
 
 	string_list_clear(&l, 0);
 
@@ -341,8 +345,8 @@ int git_diff_ui_config(const char *var, const char *value, void *cb)
 		return 0;
 	}
 	if (!strcmp(var, "diff.colormovedws")) {
-		int cm = parse_color_moved_ws(value);
-		if (cm < 0)
+		unsigned cm = parse_color_moved_ws(value);
+		if (cm & COLOR_MOVED_WS_ERROR)
 			return -1;
 		diff_color_moved_ws_default = cm;
 		return 0;
@@ -5035,7 +5039,10 @@ int diff_opt_parse(struct diff_options *options,
 			die("bad --color-moved argument: %s", arg);
 		options->color_moved = cm;
 	} else if (skip_prefix(arg, "--color-moved-ws=", &arg)) {
-		options->color_moved_ws_handling = parse_color_moved_ws(arg);
+		unsigned cm = parse_color_moved_ws(arg);
+		if (cm & COLOR_MOVED_WS_ERROR)
+			die("bad --color-moved-ws argument: %s", arg);
+		options->color_moved_ws_handling = cm;
 	} else if (skip_to_optional_arg_default(arg, "--color-words", &options->word_regex, NULL)) {
 		options->use_color = 1;
 		options->word_diff = DIFF_WORDS_COLOR;
diff --git a/diff.h b/diff.h
index ce5e8a8183..9e8061ca29 100644
--- a/diff.h
+++ b/diff.h
@@ -225,7 +225,8 @@ struct diff_options {
 
 	/* XDF_WHITESPACE_FLAGS regarding block detection are set at 2, 3, 4 */
 	#define COLOR_MOVED_WS_ALLOW_INDENTATION_CHANGE (1<<5)
-	int color_moved_ws_handling;
+	#define COLOR_MOVED_WS_ERROR (1<<0)
+	unsigned color_moved_ws_handling;
 
 	struct repository *repo;
 };
-- 
2.19.1.930.g4563a0d9d0-goog