Handle empty ref

Author: manics

__tests__/main.test.js

@@ -136,7 +136,7 @@ test("Unsupported prerelease tag", async () => {
 test("Not a tag", async () => {
   await expect(
     calculateTags("TOKEN", "owner", "repo", "something/else", "")
-  ).rejects.toEqual(new Error("Not a tag: something/else"));
+  ).rejects.toEqual(new Error("Not a tag or branch: something/else"));
 });
 
 test("Invalid semver tag", async () => {
@@ -145,6 +145,11 @@ test("Invalid semver tag", async () => {
   ).rejects.toEqual(new Error("Invalid semver tag: v1"));
 });
 
+test("No ref", async () => {
+  const tags = await calculateTags("TOKEN", "owner", "repo", null, "");
+  expect(tags).toEqual([]);
+});
+
 test("Prefix", async () => {
   const scope = nock("https://api.github.com")
     .get("/repos/owner/repo/tags")

src/index.js

@@ -14,13 +14,17 @@ function supportedPrerelease(pre) {
 async function calculateTags(token, owner, repo, ref, prefix) {
   core.debug(`ref: ${ref}`);
 
+  if (!ref) {
+    core.debug("No ref");
+    return [];
+  }
   if (ref.startsWith("refs/heads/")) {
     const branch = ref.substring(11);
-    core.debug(`Branch: branch`);
+    core.debug(`Branch: ${branch}`);
     return [`${prefix}${branch}`];
   }
   if (!ref.startsWith("refs/tags/")) {
-    throw new Error(`Not a tag: ${ref}`);
+    throw new Error(`Not a tag or branch: ${ref}`);
   }
 
   const currentTag = ref.substring(10);