config: really treat missing optional path as not configured These callers expect that git_config_pathname() that returns 0 is a signal that the variable they passed has a string they need to act on. But with the introduction of ":(optional)path" earlier, that is no longer the case. If the path specified by the configuration variable is missing, their variable will get a NULL in it, and they need to act on it (often, just refraining from copying it elsewhere). Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin/blame.c b/builtin/blame.c
index 5b10e84..1092834 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/receive-pack.c b/builtin/receive-pack.c
index 1113137..4718573 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;
 	}

diff --git a/fetch-pack.c b/fetch-pack.c
index 46c39f8..33a3f20 100644
--- a/fetch-pack.c
+++ b/fetch-pack.c

@@ -1872,8 +1872,9 @@ int fetch_pack_fsck_config(const char *var, const char *value,
 
 		if (git_config_pathname(&path, var, value))
 			return -1;
-		strbuf_addf(msg_types, "%cskiplist=%s",
-			msg_types->len ? ',' : '=', path);
+		if (path)
+			strbuf_addf(msg_types, "%cskiplist=%s",
+				    msg_types->len ? ',' : '=', path);
 		free(path);
 		return 0;
 	}

diff --git a/fsck.c b/fsck.c
index 171b424..0c28769 100644
--- a/fsck.c
+++ b/fsck.c

@@ -1351,14 +1351,16 @@ int git_fsck_config(const char *var, const char *value,
 
 	if (strcmp(var, "fsck.skiplist") == 0) {
 		char *path;
-		struct strbuf sb = STRBUF_INIT;
 
 		if (git_config_pathname(&path, var, value))
 			return -1;
-		strbuf_addf(&sb, "skiplist=%s", path);
-		free(path);
-		fsck_set_msg_types(options, sb.buf);
-		strbuf_release(&sb);
+		if (path) {
+			struct strbuf sb = STRBUF_INIT;
+			strbuf_addf(&sb, "skiplist=%s", path);
+			free(path);
+			fsck_set_msg_types(options, sb.buf);
+			strbuf_release(&sb);
+		}
 		return 0;
 	}
 

diff --git a/gpg-interface.c b/gpg-interface.c
index 06e7fb5..8b91a11 100644
--- a/gpg-interface.c
+++ b/gpg-interface.c

@@ -794,8 +794,16 @@ static int git_gpg_config(const char *var, const char *value,
 		fmtname = "ssh";
 
 	if (fmtname) {
+		char *program;
+		int status;
+
 		fmt = get_format_by_name(fmtname);
-		return git_config_pathname((char **) &fmt->program, var, value);
+		status = git_config_pathname(&program, var, value);
+		if (status)
+			return status;
+		if (program)
+			fmt->program = program;
+		return status;
 	}
 
 	return 0;

diff --git a/setup.c b/setup.c
index 98ddbf3..18301b5 100644
--- a/setup.c
+++ b/setup.c

@@ -1248,7 +1248,7 @@ static int safe_directory_cb(const char *key, const char *value,
 	} else {
 		char *allowed = NULL;
 
-		if (!git_config_pathname(&allowed, key, value)) {
+		if (!git_config_pathname(&allowed, key, value) && allowed) {
 			char *normalized = NULL;
 
 			/*