Only set commit-lockfile-summary when commit-msg is defined

action.yml

@@ -12,7 +12,7 @@ inputs:
   commit-msg:
     description: "The message provided with the commit"
     required: false
-    default: "flake.lock: Update"
+    default: ""
   base:
     description: "Sets the pull request base branch. Defaults to the branch checked out in the workflow."
     required: false

dist/index.js

@@ -95326,11 +95326,7 @@ function makeNixCommandArgs(nixOptions, flakeInputs, commitMessage) {
     "--update-input",
     input
   ]);
-  const lockfileSummaryFlags = [
-    "--option",
-    "commit-lockfile-summary",
-    commitMessage
-  ];
+  const lockfileSummaryFlags = commitMessage ? ["--option", "commit-lockfile-summary", commitMessage] : [];
   const updateLockMechanism = flakeInputFlags.length === 0 ? "update" : "lock";
   return nixOptions.concat(["flake", updateLockMechanism]).concat(flakeInputFlags).concat(["--commit-lock-file"]).concat(lockfileSummaryFlags);
 }

src/nix.test.ts

@@ -12,6 +12,14 @@ type TestCase = {
 
 test("Nix command arguments", () => {
   const testCases: TestCase[] = [
+    {
+      inputs: {
+        nixOptions: [],
+        flakeInputs: [],
+        commitMessage: "",
+      },
+      expected: ["flake", "update", "--commit-lock-file"],
+    },
     {
       inputs: {
         nixOptions: ["--log-format", "raw"],

src/nix.ts

@@ -15,11 +15,9 @@ export function makeNixCommandArgs(
   // configured via `--option <alias name> <option value>`
   // (https://github.com/NixOS/nix/issues/10989).
   // So, we go the long way so that we can support versions both before and after Nix 2.23.0.
-  const lockfileSummaryFlags = [
-    "--option",
-    "commit-lockfile-summary",
-    commitMessage,
-  ];
+  const lockfileSummaryFlags = commitMessage
+    ? ["--option", "commit-lockfile-summary", commitMessage]
+    : [];
 
   const updateLockMechanism = flakeInputFlags.length === 0 ? "update" : "lock";