config: make 'git config list --type=<X>' work

Previously, the --type=<X> argument to 'git config list' was ignored and
did nothing. Now, we add the use of format_config() to the
show_all_config() function so each key-value pair is attempted to be
parsed. This is our first use of the 'gently' parameter with a nonzero
value.

When listing multiple values, our initial settings for the output format
is different. Add a new init helper to specify the fact that keys should
be shown and also add the default delimiters as they were unset in some
cases.

If there is an error in parsing, then the row is not output.

This is a change in behavior! We are starting to respect an option that
was previously ignored, leading to potential user confusion. This is
probably still a good option, since the --type argument did not change
behavior at all previously, so users can get the behavior they expect by
removing the --type argument or adding the --no-type argument.

Signed-off-by: Derrick Stolee <stolee@gmail.com>

Author: derrickstolee

Documentation/git-config.adoc

@@ -240,6 +240,9 @@ Valid `<type>`'s include:
   that the given value is canonicalize-able as an ANSI color, but it is written
   as-is.
 +
+If the command is in `list` mode, then the `--type <type>` argument will apply
+to each listed config value. If the value does not successfully parse in that
+format, then it will be omitted from the list.
 
 --bool::
 --int::

builtin/config.c

@@ -450,21 +450,12 @@ static int show_all_config(const char *key_, const char *value_,
 {
 	const struct config_display_options *opts = cb;
 	const struct key_value_info *kvi = ctx->kvi;
+	struct strbuf formatted = STRBUF_INIT;
 
-	if (opts->show_origin || opts->show_scope) {
-		struct strbuf buf = STRBUF_INIT;
-		if (opts->show_scope)
-			show_config_scope(opts, kvi, &buf);
-		if (opts->show_origin)
-			show_config_origin(opts, kvi, &buf);
-		/* Use fwrite as "buf" can contain \0's if "end_null" is set. */
-		fwrite(buf.buf, 1, buf.len, stdout);
-		strbuf_release(&buf);
-	}
-	if (!opts->omit_values && value_)
-		printf("%s%c%s%c", key_, opts->delim, value_, opts->term);
-	else
-		printf("%s%c", key_, opts->term);
+	if (format_config(opts, &formatted, key_, value_, kvi, 1) >= 0)
+		fwrite(formatted.buf, 1, formatted.len, stdout);
+
+	strbuf_release(&formatted);
 	return 0;
 }
 
@@ -1004,6 +995,19 @@ static void display_options_init(struct config_display_options *opts)
 	}
 }
 
+static void display_options_init_list(struct config_display_options *opts)
+{
+	opts->show_keys = 1;
+
+	if (opts->end_nul) {
+		display_options_init(opts);
+	} else {
+		opts->term = '\n';
+		opts->delim = ' ';
+		opts->key_delim = '=';
+	}
+}
+
 static int cmd_config_list(int argc, const char **argv, const char *prefix,
 			   struct repository *repo UNUSED)
 {
@@ -1022,7 +1026,7 @@ static int cmd_config_list(int argc, const char **argv, const char *prefix,
 	check_argc(argc, 0, 0);
 
 	location_options_init(&location_opts, prefix);
-	display_options_init(&display_opts);
+	display_options_init_list(&display_opts);
 
 	setup_auto_pager("config", 1);
 
@@ -1453,6 +1457,7 @@ static int cmd_config_actions(int argc, const char **argv, const char *prefix)
 
 	if (actions == ACTION_LIST) {
 		check_argc(argc, 0, 0);
+		display_options_init_list(&display_opts);
 		if (config_with_options(show_all_config, &display_opts,
 					&location_opts.source, the_repository,
 					&location_opts.options) < 0) {

t/t1300-config.sh

@@ -2459,9 +2459,12 @@ done
 
 cat >.git/config <<-\EOF &&
 [section]
-foo = true
+foo = True
 number = 10
 big = 1M
+path = ~/dir
+red = red
+blue = Blue
 EOF
 
 test_expect_success 'identical modern --type specifiers are allowed' '
@@ -2503,6 +2506,44 @@ test_expect_success 'unset type specifiers may be reset to conflicting ones' '
 	test_cmp_config 1048576 --type=bool --no-type --type=int section.big
 '
 
+test_expect_success 'list --type=bool shows only canonicalizable bool values' '
+	cat >expect <<-EOF &&
+	section.foo=true
+	section.number=true
+	section.big=true
+	EOF
+
+	git config ${mode_prefix}list --type=bool >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'list --type=path shows only canonicalizable path values' '
+	cat >expect <<-EOF &&
+	section.foo=True
+	section.number=10
+	section.big=1M
+	section.path=$HOME/dir
+	section.red=red
+	section.blue=Blue
+	EOF
+
+	git config ${mode_prefix}list --type=path >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'list --type=color shows only canonicalizable color values' '
+	cat >expect <<-EOF &&
+	section.number=<>
+	section.red=<RED>
+	section.blue=<BLUE>
+	EOF
+
+	git config ${mode_prefix}list --type=color >actual.raw 2>err &&
+	test_decode_color <actual.raw >actual &&
+	test_cmp expect actual &&
+	test_must_be_empty err
+'
+
 test_expect_success '--type rejects unknown specifiers' '
 	test_must_fail git config --type=nonsense section.foo 2>error &&
 	test_grep "unrecognized --type argument" error