config: distinguish between a lone variable name and one without rhs

'[section] variable' and '[section] variable =' behave differently
when parsed as booleans, so we need to store that distinction
internally.

src/config_file.c

@@ -1432,8 +1432,10 @@ static int parse_variable(diskfile_backend *cfg, char **var_name, char **var_val
 		else if (value_start[0] != '\0') {
 			*var_value = fixup_line(value_start, 0);
 			GITERR_CHECK_ALLOC(*var_value);
+		} else { /* equals sign but missing rhs */
+			*var_value = git__strdup("");
+			GITERR_CHECK_ALLOC(*var_value);
 		}
-
 	}
 
 	git__free(line);

src/remote.c

@@ -136,7 +136,7 @@ int git_remote_load(git_remote **out, git_repository *repo, const char *name)
 	if ((error = git_config_get_string(&val, config, git_buf_cstr(&buf))) < 0)
 		goto cleanup;
 	
-	if (!val) {
+	if (!val || strlen(val) == 0) {
 		giterr_set(GITERR_INVALID, "Malformed remote '%s' - missing URL", name);
 		error = -1;
 		goto cleanup;

src/util.c

@@ -432,12 +432,8 @@ int git__strcmp_cb(const void *a, const void *b)
 int git__parse_bool(int *out, const char *value)
 {
 	/* A missing value means true */
-	if (value == NULL) {
-		*out = 1;
-		return 0;
-	}
-
-	if (!strcasecmp(value, "true") ||
+	if (value == NULL ||
+		!strcasecmp(value, "true") ||
 		!strcasecmp(value, "yes") ||
 		!strcasecmp(value, "on")) {
 		*out = 1;
@@ -445,7 +441,8 @@ int git__parse_bool(int *out, const char *value)
 	}
 	if (!strcasecmp(value, "false") ||
 		!strcasecmp(value, "no") ||
-		!strcasecmp(value, "off")) {
+		!strcasecmp(value, "off") ||
+		value[0] == '\0') {
 		*out = 0;
 		return 0;
 	}

tests-clar/config/read.c

@@ -93,6 +93,12 @@ void test_config_read__lone_variable(void)
 	cl_git_pass(git_config_get_bool(&i, cfg, "some.section.variable"));
 	cl_assert(i == 1);
 
+	cl_git_pass(git_config_get_string(&str, cfg, "some.section.variableeq"));
+	cl_assert_equal_s(str, "");
+
+	cl_git_pass(git_config_get_bool(&i, cfg, "some.section.variableeq"));
+	cl_assert(i == 0);
+
 	git_config_free(cfg);
 }
 

tests-clar/resources/config/config4

 # A variable name on its own is valid
 [some.section]
 		variable
+# A variable and '=' is accepted, but it's not considered true
+		variableeq =