Support reading from body-file

.github/commenter.yml

@@ -19,3 +19,8 @@ Frontend:
     - [ ] Do this
     - [ ] And this
     - [ ] And that
+
+Prelude:
+  where:
+    path:
+      matches: "backend/**/*"

.github/commenter/Prelude.md

@@ -0,0 +1,6 @@
+You've modified our Prelude!
+
+Please read the following links:
+
+- ...
+- ...

README.md

@@ -110,6 +110,14 @@ CommentOnAutomatedUpdate:
     integrity of the packages being updated.
 ```
 
+## Reading the Comment Body from a File
+
+If `body` is omitted, a file named `.github/commenter/{name}.md` is read from
+the default branch for the comment contents. The `.github/commenter/` prefix can
+be changed via `inputs.body-file-prefix`. The complete path, or just the name
+part, can be specified via the `body-file` and `body-file-name` attributes of
+the configuration, respectively.
+
 ## Acknowledgements
 
 This action was highly inspired by (and began as a copy of)

__tests__/fixtures/body_file.yml

@@ -0,0 +1,4 @@
+Prelude:
+  where:
+    path:
+      matches: "Prelude.hs"

__tests__/main.test.ts

@@ -22,6 +22,7 @@ const yamlFixtures = {
   "all_conditions.yml": fs.readFileSync(
     "__tests__/fixtures/all_conditions.yml",
   ),
+  "body_file.yml": fs.readFileSync("__tests__/fixtures/body_file.yml"),
 };
 
 afterAll(() => jest.restoreAllMocks());
@@ -185,11 +186,31 @@ describe("run", () => {
       body: "This change requires human review\n",
     });
   });
+
+  it("adds comments from file contents", async () => {
+    usingConfigYaml("body_file.yml");
+    mockGitHubResponseGetContentOnce("Some content\n");
+    mockGitHubResponseChangedFiles("Prelude.hs");
+
+    await run();
+
+    expect(createCommentMock).toHaveBeenCalledTimes(1);
+    expect(createCommentMock).toHaveBeenCalledWith({
+      owner: "monalisa",
+      repo: "helloworld",
+      issue_number: 123,
+      body: "Some content\n",
+    });
+  });
 });
 
 function usingConfigYaml(fixtureName: keyof typeof yamlFixtures): void {
-  reposMock.mockResolvedValue(<any>{
-    data: { content: yamlFixtures[fixtureName], encoding: "utf8" },
+  mockGitHubResponseGetContentOnce(yamlFixtures[fixtureName]);
+}
+
+function mockGitHubResponseGetContentOnce(content: string): void {
+  reposMock.mockResolvedValueOnce(<any>{
+    data: { content, encoding: "utf8" },
   });
 }
 

action.yml

@@ -9,6 +9,10 @@ inputs:
     description: "The path for the comment configurations"
     default: ".github/commenter.yml"
     required: false
+  body-file-prefix:
+    description: "The path for finding body markdown files"
+    default: ".github/commenter/"
+    required: false
 
 runs:
   using: "node20"