1 files changed, 22 insertions, 5 deletions
diff --git a/diff.c b/diff.c
index 587341805c..a89a6a6128 100644
--- a/diff.c
+++ b/diff.c
@@ -370,7 +370,10 @@ int git_diff_ui_config(const char *var, const char *value,
 		return 0;
 	}
 	if (!strcmp(var, "diff.colormovedws")) {
-		unsigned cm = parse_color_moved_ws(value);
+		unsigned cm;
+		if (!value)
+			return config_error_nonbool(var);
+		cm = parse_color_moved_ws(value);
 		if (cm & COLOR_MOVED_WS_ERROR)
 			return -1;
 		diff_color_moved_ws_default = cm;
@@ -424,10 +427,15 @@ int git_diff_ui_config(const char *var, const char *value,
 	if (!strcmp(var, "diff.orderfile"))
 		return git_config_pathname(&diff_order_file_cfg, var, value);
 
-	if (!strcmp(var, "diff.ignoresubmodules"))
+	if (!strcmp(var, "diff.ignoresubmodules")) {
+		if (!value)
+			return config_error_nonbool(var);
 		handle_ignore_submodules_arg(&default_diff_options, value);
+	}
 
 	if (!strcmp(var, "diff.submodule")) {
+		if (!value)
+			return config_error_nonbool(var);
 		if (parse_submodule_params(&default_diff_options, value))
 			warning(_("Unknown value for 'diff.submodule' config variable: '%s'"),
 				value);
@@ -435,9 +443,12 @@ int git_diff_ui_config(const char *var, const char *value,
 	}
 
 	if (!strcmp(var, "diff.algorithm")) {
+		if (!value)
+			return config_error_nonbool(var);
 		diff_algorithm = parse_algorithm_value(value);
 		if (diff_algorithm < 0)
-			return -1;
+			return error(_("unknown value for config '%s': %s"),
+				     var, value);
 		return 0;
 	}
 
@@ -471,9 +482,13 @@ int git_diff_basic_config(const char *var, const char *value,
 	}
 
 	if (!strcmp(var, "diff.wserrorhighlight")) {
-		int val = parse_ws_error_highlight(value);
+		int val;
+		if (!value)
+			return config_error_nonbool(var);
+		val = parse_ws_error_highlight(value);
 		if (val < 0)
-			return -1;
+			return error(_("unknown value for config '%s': %s"),
+				     var, value);
 		ws_error_highlight_default = val;
 		return 0;
 	}
@@ -488,6 +503,8 @@ int git_diff_basic_config(const char *var, const char *value,
 
 	if (!strcmp(var, "diff.dirstat")) {
 		struct strbuf errmsg = STRBUF_INIT;
+		if (!value)
+			return config_error_nonbool(var);
 		default_diff_options.dirstat_permille = diff_dirstat_permille_default;
 		if (parse_dirstat_params(&default_diff_options, value, &errmsg))
 			warning(_("Found errors in 'diff.dirstat' config variable:\n%s"),