Subject: [PATCH] config: really treat missing optional path as not configured

From: Junio C Hamano <[email-masked]>
Date: Thu, 20 Nov 2025 11:45:35 -0800

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 <[email-masked]>
---
 builtin/blame.c        |  3 ++-
 builtin/receive-pack.c |  5 +++--
 fetch-pack.c           |  5 +++--
 fsck.c                 | 12 +++++++-----
 gpg-interface.c        | 10 +++++++++-
 setup.c                |  2 +-
 6 files changed, 25 insertions(+), 12 deletions(-)

diff --git a/builtin/blame.c b/builtin/blame.c
index 2703820258..c39c1d3149 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 c9288a9c7e..c6e8e8346e 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 fe7a84bf2f..7162fd3ba2 100644
--- a/fetch-pack.c
+++ b/fetch-pack.c
@@ -1873,8 +1873,9 @@ 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 341e100d24..cf6f7f3a61 100644
--- a/fsck.c
+++ b/fsck.c
@@ -1369,14 +1369,16 @@ 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 f680ed38c0..3e73513694 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 7086741e6c..cf47441b7b 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;
 
 			/*
-- 
2.52.0-101-g4c43c53c49