Merge branch 'cc/skip-to-optional-val'

Introduce a helper to simplify code to parse a common pattern that
expects either "--key" or "--key=<something>".

* cc/skip-to-optional-val:
  t4045: reindent to make helpers readable
  diff: add tests for --relative without optional prefix value
  diff: use skip_to_optional_arg_default() in parsing --relative
  diff: use skip_to_optional_arg_default()
  diff: use skip_to_optional_arg()
  index-pack: use skip_to_optional_arg()
  git-compat-util: introduce skip_to_optional_arg()

1 files changed, 16 insertions, 34 deletions

diff --git a/diff.c b/diff.c
index 3fb445a54d..fb22b19f09 100644
--- a/diff.c
+++ b/diff.c
@@ -4512,17 +4512,12 @@ int diff_opt_parse(struct diff_options *options,
 		options->output_format |= DIFF_FORMAT_NUMSTAT;
 	else if (!strcmp(arg, "--shortstat"))
 		options->output_format |= DIFF_FORMAT_SHORTSTAT;
-	else if (!strcmp(arg, "-X") || !strcmp(arg, "--dirstat"))
-		return parse_dirstat_opt(options, "");
-	else if (skip_prefix(arg, "-X", &arg))
-		return parse_dirstat_opt(options, arg);
-	else if (skip_prefix(arg, "--dirstat=", &arg))
+	else if (skip_prefix(arg, "-X", &arg) ||
+		 skip_to_optional_arg(arg, "--dirstat", &arg))
 		return parse_dirstat_opt(options, arg);
 	else if (!strcmp(arg, "--cumulative"))
 		return parse_dirstat_opt(options, "cumulative");
-	else if (!strcmp(arg, "--dirstat-by-file"))
-		return parse_dirstat_opt(options, "files");
-	else if (skip_prefix(arg, "--dirstat-by-file=", &arg)) {
+	else if (skip_to_optional_arg(arg, "--dirstat-by-file", &arg)) {
 		parse_dirstat_opt(options, "files");
 		return parse_dirstat_opt(options, arg);
 	}
@@ -4544,13 +4539,13 @@ int diff_opt_parse(struct diff_options *options,
 		return stat_opt(options, av);
 
 	/* renames options */
-	else if (starts_with(arg, "-B") || starts_with(arg, "--break-rewrites=") ||
-		 !strcmp(arg, "--break-rewrites")) {
+	else if (starts_with(arg, "-B") ||
+		 skip_to_optional_arg(arg, "--break-rewrites", NULL)) {
 		if ((options->break_opt = diff_scoreopt_parse(arg)) == -1)
 			return error("invalid argument to -B: %s", arg+2);
 	}
-	else if (starts_with(arg, "-M") || starts_with(arg, "--find-renames=") ||
-		 !strcmp(arg, "--find-renames")) {
+	else if (starts_with(arg, "-M") ||
+		 skip_to_optional_arg(arg, "--find-renames", NULL)) {
 		if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
 			return error("invalid argument to -M: %s", arg+2);
 		options->detect_rename = DIFF_DETECT_RENAME;
@@ -4558,8 +4553,8 @@ int diff_opt_parse(struct diff_options *options,
 	else if (!strcmp(arg, "-D") || !strcmp(arg, "--irreversible-delete")) {
 		options->irreversible_delete = 1;
 	}
-	else if (starts_with(arg, "-C") || starts_with(arg, "--find-copies=") ||
-		 !strcmp(arg, "--find-copies")) {
+	else if (starts_with(arg, "-C") ||
+		 skip_to_optional_arg(arg, "--find-copies", NULL)) {
 		if (options->detect_rename == DIFF_DETECT_COPY)
 			options->flags.find_copies_harder = 1;
 		if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
@@ -4572,11 +4567,10 @@ int diff_opt_parse(struct diff_options *options,
 		options->flags.rename_empty = 1;
 	else if (!strcmp(arg, "--no-rename-empty"))
 		options->flags.rename_empty = 0;
-	else if (!strcmp(arg, "--relative"))
-		options->flags.relative_name = 1;
-	else if (skip_prefix(arg, "--relative=", &arg)) {
+	else if (skip_to_optional_arg_default(arg, "--relative", &arg, NULL)) {
 		options->flags.relative_name = 1;
-		options->prefix = arg;
+		if (arg)
+			options->prefix = arg;
 	}
 
 	/* xdiff options */
@@ -4646,9 +4640,7 @@ int diff_opt_parse(struct diff_options *options,
 	else if (!strcmp(arg, "--no-follow")) {
 		options->flags.follow_renames = 0;
 		options->flags.default_follow_renames = 0;
-	} else if (!strcmp(arg, "--color"))
-		options->use_color = 1;
-	else if (skip_prefix(arg, "--color=", &arg)) {
+	} else if (skip_to_optional_arg_default(arg, "--color", &arg, "always")) {
 		int value = git_config_colorbool(NULL, arg);
 		if (value < 0)
 			return error("option `color' expects \"always\", \"auto\", or \"never\"");
@@ -4668,14 +4660,9 @@ int diff_opt_parse(struct diff_options *options,
 		if (cm < 0)
 			die("bad --color-moved argument: %s", arg);
 		options->color_moved = cm;
-	} else if (!strcmp(arg, "--color-words")) {
-		options->use_color = 1;
-		options->word_diff = DIFF_WORDS_COLOR;
-	}
-	else if (skip_prefix(arg, "--color-words=", &arg)) {
+	} else if (skip_to_optional_arg_default(arg, "--color-words", &options->word_regex, NULL)) {
 		options->use_color = 1;
 		options->word_diff = DIFF_WORDS_COLOR;
-		options->word_regex = arg;
 	}
 	else if (!strcmp(arg, "--word-diff")) {
 		if (options->word_diff == DIFF_WORDS_NONE)
@@ -4714,15 +4701,10 @@ int diff_opt_parse(struct diff_options *options,
 		options->flags.textconv_set_via_cmdline = 1;
 	} else if (!strcmp(arg, "--no-textconv"))
 		options->flags.allow_textconv = 0;
-	else if (!strcmp(arg, "--ignore-submodules")) {
-		options->flags.override_submodule_config = 1;
-		handle_ignore_submodules_arg(options, "all");
-	} else if (skip_prefix(arg, "--ignore-submodules=", &arg)) {
+	else if (skip_to_optional_arg_default(arg, "--ignore-submodules", &arg, "all")) {
 		options->flags.override_submodule_config = 1;
 		handle_ignore_submodules_arg(options, arg);
-	} else if (!strcmp(arg, "--submodule"))
-		options->submodule_format = DIFF_SUBMODULE_LOG;
-	else if (skip_prefix(arg, "--submodule=", &arg))
+	} else if (skip_to_optional_arg_default(arg, "--submodule", &arg, "log"))
 		return parse_submodule_opt(options, arg);
 	else if (skip_prefix(arg, "--ws-error-highlight=", &arg))
 		return parse_ws_error_highlight_opt(options, arg);