config: teach "git -c" to recognize an empty string

In a config file, you can do:

[foo]
bar

to turn the "foo.bar" boolean flag on, and you can do:

[foo]
bar=

to set "foo.bar" to the empty string. However, git's "-c"
parameter treats both:

git -c foo.bar

and

git -c foo.bar=

as the boolean flag, and there is no way to set a variable
to the empty string. This patch enables the latter form to
do that.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/Documentation/git.txt b/Documentation/git.txt
index 64da795aba252d53e9fd9c11e6eb7d39397ff805..1557cd919d4ecf9133d1cd2cd449ead4b78c7f7f 100644 (file)
--- a/Documentation/git.txt
+++ b/Documentation/git.txt
@@ -429,6 +429,11 @@ example the following invocations are equivalent:
        given will override values from configuration files.
        The <name> is expected in the same format as listed by
        'git config' (subkeys separated by dots).
++
+Note that omitting the `=` in `git -c foo.bar ...` is allowed and sets
+`foo.bar` to the boolean true value (just like `[foo]bar` would in a
+config file). Including the equals but with an empty value (like `git -c
+foo.bar= ...`) sets `foo.bar` to the empty string.
 
 --exec-path[=<path>]::
        Path to wherever your core Git programs are installed.

diff --git a/config.c b/config.c
index e1d66a145b756c49c4e4902200c354499532a428..5390a63acb372eaa18ba4e83022789155fcc1c1f 100644 (file)
--- a/config.c
+++ b/config.c
@@ -164,19 +164,27 @@ void git_config_push_parameter(const char *text)
 int git_config_parse_parameter(const char *text,
                               config_fn_t fn, void *data)
 {
+       const char *value;
        struct strbuf **pair;
+
        pair = strbuf_split_str(text, '=', 2);
        if (!pair[0])
                return error("bogus config parameter: %s", text);
-       if (pair[0]->len && pair[0]->buf[pair[0]->len - 1] == '=')
+
+       if (pair[0]->len && pair[0]->buf[pair[0]->len - 1] == '=') {
                strbuf_setlen(pair[0], pair[0]->len - 1);
+               value = pair[1] ? pair[1]->buf : "";
+       } else {
+               value = NULL;
+       }
+
        strbuf_trim(pair[0]);
        if (!pair[0]->len) {
                strbuf_list_free(pair);
                return error("bogus config parameter: %s", text);
        }
        lowercase(pair[0]->buf);
-       if (fn(pair[0]->buf, pair[1] ? pair[1]->buf : NULL, data) < 0) {
+       if (fn(pair[0]->buf, value, data) < 0) {
                strbuf_list_free(pair);
                return -1;
        }

diff --git a/t/t1300-repo-config.sh b/t/t1300-repo-config.sh
index 967359344dab8118dfd55816ef08f4809a9f33ad..38917da0ef764be20b58a59a5c254ebdbb2c891e 100755 (executable)
--- a/t/t1300-repo-config.sh
+++ b/t/t1300-repo-config.sh
@@ -1006,6 +1006,17 @@ test_expect_success 'git -c "key=value" support' '
        test_must_fail git -c name=value config core.name
 '
 
+# We just need a type-specifier here that cares about the
+# distinction internally between a NULL boolean and a real
+# string (because most of git's internal parsers do care).
+# Using "--path" works, but we do not otherwise care about
+# its semantics.
+test_expect_success 'git -c can represent empty string' '
+       echo >expect &&
+       git -c foo.empty= config --path foo.empty >actual &&
+       test_cmp expect actual
+'
+
 test_expect_success 'key sanity-checking' '
        test_must_fail git config foo=bar &&
        test_must_fail git config foo=.bar &&