Merge branch 'jc/optional-path'

"git config get --path" segfaulted on an ":(optional)path" that
does not exist, which has been corrected.

* jc/optional-path:
  config: really treat missing optional path as not configured
  config: really pretend missing :(optional) value is not there
  config: mark otherwise unused function as file-scope static

3 files changed, 41 insertions, 12 deletions

diff --git a/builtin/blame.c b/builtin/blame.c
index 27b513d27f..6044973462 100644
--- a/builtin/blame.c
+++ b/builtin/blame.c
@@ -739,7 +739,8 @@ static int git_blame_config(const char *var, const char *value,
 		ret = git_config_pathname(&str, var, value);
 		if (ret)
 			return ret;
-		string_list_insert(&ignore_revs_file_list, str);
+		if (str)
+			string_list_insert(&ignore_revs_file_list, str);
 		free(str);
 		return 0;
 	}
diff --git a/builtin/config.c b/builtin/config.c
index 75852bd79d..e58eb6a176 100644
--- a/builtin/config.c
+++ b/builtin/config.c
@@ -261,6 +261,12 @@ struct strbuf_list {
 	int alloc;
 };
 
+/*
+ * Format the configuration key-value pair (`key_`, `value_`) and
+ * append it into strbuf `buf`.  Returns a negative value on failure,
+ * 0 on success, 1 on a missing optional value (i.e., telling the
+ * caller to pretend that <key_,value_> did not exist).
+ */
 static int format_config(const struct config_display_options *opts,
 			 struct strbuf *buf, const char *key_,
 			 const char *value_, const struct key_value_info *kvi)
@@ -299,7 +305,10 @@ static int format_config(const struct config_display_options *opts,
 			char *v;
 			if (git_config_pathname(&v, key_, value_) < 0)
 				return -1;
-			strbuf_addstr(buf, v);
+			if (v)
+				strbuf_addstr(buf, v);
+			else
+				return 1; /* :(optional)no-such-file */
 			free((char *)v);
 		} else if (opts->type == TYPE_EXPIRY_DATE) {
 			timestamp_t t;
@@ -344,6 +353,7 @@ static int collect_config(const char *key_, const char *value_,
 	struct collect_config_data *data = cb;
 	struct strbuf_list *values = data->values;
 	const struct key_value_info *kvi = ctx->kvi;
+	int status;
 
 	if (!(data->get_value_flags & GET_VALUE_KEY_REGEXP) &&
 	    strcmp(key_, data->key))
@@ -361,8 +371,15 @@ static int collect_config(const char *key_, const char *value_,
 	ALLOC_GROW(values->items, values->nr + 1, values->alloc);
 	strbuf_init(&values->items[values->nr], 0);
 
-	return format_config(data->display_opts, &values->items[values->nr++],
-			     key_, value_, kvi);
+	status = format_config(data->display_opts, &values->items[values->nr++],
+			       key_, value_, kvi);
+	if (status < 0)
+		return status;
+	if (status) {
+		strbuf_release(&values->items[--values->nr]);
+		status = 0;
+	}
+	return status;
 }
 
 static int get_value(const struct config_location_options *opts,
@@ -438,15 +455,23 @@ static int get_value(const struct config_location_options *opts,
 	if (!values.nr && display_opts->default_value) {
 		struct key_value_info kvi = KVI_INIT;
 		struct strbuf *item;
+		int status;
 
 		kvi_from_param(&kvi);
 		ALLOC_GROW(values.items, values.nr + 1, values.alloc);
 		item = &values.items[values.nr++];
 		strbuf_init(item, 0);
-		if (format_config(display_opts, item, key_,
-				  display_opts->default_value, &kvi) < 0)
+
+		status = format_config(display_opts, item, key_,
+				       display_opts->default_value, &kvi);
+		if (status < 0)
 			die(_("failed to format default config value: %s"),
 			    display_opts->default_value);
+		if (status) {
+			/* default was a missing optional value */
+			values.nr--;
+			strbuf_release(item);
+		}
 	}
 
 	ret = !values.nr;
@@ -714,11 +739,13 @@ static int get_urlmatch(const struct config_location_options *opts,
 	for_each_string_list_item(item, &values) {
 		struct urlmatch_current_candidate_value *matched = item->util;
 		struct strbuf buf = STRBUF_INIT;
+		int status;
 
-		format_config(&display_opts, &buf, item->string,
-			      matched->value_is_null ? NULL : matched->value.buf,
-			      &matched->kvi);
-		fwrite(buf.buf, 1, buf.len, stdout);
+		status = format_config(&display_opts, &buf, item->string,
+				       matched->value_is_null ? NULL : matched->value.buf,
+				       &matched->kvi);
+		if (!status)
+			fwrite(buf.buf, 1, buf.len, stdout);
 		strbuf_release(&buf);
 
 		strbuf_release(&matched->value);
diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index e8ee0e7321..28a6404219 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -177,8 +177,9 @@ static int receive_pack_config(const char *var, const char *value,
 
 		if (git_config_pathname(&path, var, value))
 			return -1;
-		strbuf_addf(&fsck_msg_types, "%cskiplist=%s",
-			fsck_msg_types.len ? ',' : '=', path);
+		if (path)
+			strbuf_addf(&fsck_msg_types, "%cskiplist=%s",
+				    fsck_msg_types.len ? ',' : '=', path);
 		free(path);
 		return 0;
 	}