fix: gracefully fallback to body when body_path cannot be read (#671)

* Initial plan

* fix: gracefully fallback to body when body_path cannot be read

Co-authored-by: chenrui333 <1580956+chenrui333@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: chenrui333 <1580956+chenrui333@users.noreply.github.com>

Author: Copilot

__tests__/util.test.ts

@@ -122,6 +122,52 @@ describe('util', () => {
         }),
       );
     });
+    it('falls back to body when body_path is missing', () => {
+      assert.equal(
+        releaseBody({
+          github_ref: '',
+          github_repository: '',
+          github_token: '',
+          input_body: 'fallback-body',
+          input_body_path: '__tests__/does-not-exist.txt',
+          input_draft: false,
+          input_prerelease: false,
+          input_files: [],
+          input_overwrite_files: undefined,
+          input_preserve_order: undefined,
+          input_name: undefined,
+          input_tag_name: undefined,
+          input_target_commitish: undefined,
+          input_discussion_category_name: undefined,
+          input_generate_release_notes: false,
+          input_make_latest: undefined,
+        }),
+        'fallback-body',
+      );
+    });
+    it('returns undefined when body_path is missing and body is not provided', () => {
+      assert.equal(
+        releaseBody({
+          github_ref: '',
+          github_repository: '',
+          github_token: '',
+          input_body: undefined,
+          input_body_path: '__tests__/does-not-exist.txt',
+          input_draft: false,
+          input_prerelease: false,
+          input_files: [],
+          input_overwrite_files: undefined,
+          input_preserve_order: undefined,
+          input_name: undefined,
+          input_tag_name: undefined,
+          input_target_commitish: undefined,
+          input_discussion_category_name: undefined,
+          input_generate_release_notes: false,
+          input_make_latest: undefined,
+        }),
+        undefined,
+      );
+    });
   });
   describe('parseConfig', () => {
     it('parses basic config', () => {

src/util.ts

@@ -35,10 +35,17 @@ export const uploadUrl = (url: string): string => {
 };
 
 export const releaseBody = (config: Config): string | undefined => {
-  return (
-    (config.input_body_path && readFileSync(config.input_body_path).toString('utf8')) ||
-    config.input_body
-  );
+  if (config.input_body_path) {
+    try {
+      const contents = readFileSync(config.input_body_path, 'utf8');
+      return contents;
+    } catch (err: any) {
+      console.warn(
+        `⚠️ Failed to read body_path "${config.input_body_path}" (${err?.code ?? 'ERR'}). Falling back to 'body' input.`,
+      );
+    }
+  }
+  return config.input_body;
 };
 
 type Env = { [key: string]: string | undefined };