Initial version of PR body rendering

action.yml

@@ -16,7 +16,7 @@ inputs:
       * `{{ flake_dot_lock }}` is the path to the `flake.lock` file being updated
       * `{{ flake_dot_lock_dir }}` is the `flake.lock` file's directory
 
-      If you set both this and `commit-msg`, the `commit-msg` setting is used.
+      If you set both this and `commit-msg`, the `commit-msg` setting is used (it does not support templating).
     required: false
     default: |
       flake.lock: Updated in {{ flake_dot_lock_dir }}
@@ -48,7 +48,13 @@ inputs:
     default: "flake.lock: Update"
   pr-body-template:
     description: |
-      TODO
+      The pull request body template to use. You can use these variables in your template:
+
+      * `{{ comma_separated_dirs }}` is the flake directories that were updated separated by comma
+      * `{{ space_separated_dirs }}` is the flake directories that were updated separated by space
+      * `{{ updated_dirs_list }}` is the flake directories that were updated as a Markdown list
+
+      If you set both this and `pr-body`, the `pr-body` setting is used (it does not support templating).
     required: false
     default: |
       Just testing.

src/index.ts

@@ -1,5 +1,5 @@
 import { makeNixCommandArgs } from "./nix.js";
-import { renderCommitMessage } from "./template.js";
+import { renderCommitMessage, renderPullRequestBody } from "./template.js";
 import * as actionsCore from "@actions/core";
 import * as actionsExec from "@actions/exec";
 import { DetSysAction, inputs } from "detsys-ts";
@@ -14,6 +14,8 @@ const EVENT_EXECUTION_FAILURE = "execution_failure";
 class UpdateFlakeLockAction extends DetSysAction {
   private commitMessage: string;
   private commitMessageTemplate: string;
+  private prBody: string;
+  private prBodyTemplate: string;
   private nixOptions: string[];
   private flakeInputs: string[];
   private pathToFlakeDir: string | null;
@@ -29,6 +31,8 @@ class UpdateFlakeLockAction extends DetSysAction {
 
     this.commitMessage = inputs.getString("commit-msg");
     this.commitMessageTemplate = inputs.getString("commit-msg-template");
+    this.prBody = inputs.getString("pr-body");
+    this.prBodyTemplate = inputs.getString("pr-body-template");
     this.flakeInputs = inputs.getArrayOfStrings("inputs", "space");
     this.nixOptions = inputs.getArrayOfStrings("nix-options", "space");
     this.pathToFlakeDir = inputs.getStringOrNull("path-to-flake-dir");
@@ -48,7 +52,12 @@ class UpdateFlakeLockAction extends DetSysAction {
       await this.updateFlakeInDirectory(directory);
     }
 
-    actionsCore.setOutput(PR_BODY_OUTPUT_KEY, "THIS IS JUST A TEST");
+    const prBody =
+      this.prBody !== ""
+        ? this.prBody
+        : renderPullRequestBody(this.prBodyTemplate, this.flakeDirs);
+
+    actionsCore.setOutput(PR_BODY_OUTPUT_KEY, prBody);
   }
 
   // No post phase

src/template.test.ts

@@ -46,13 +46,30 @@ describe("templating", () => {
   test("pull request body", () => {
     type TestCase = {
       template: string;
+      dirs: string[];
       expected: string;
     };
 
-    const testCases: TestCase[] = [];
+    const testCases: TestCase[] = [
+      {
+        template: "Updated inputs: {{ comma_separated_dirs }}",
+        dirs: ["."],
+        expected: "Updated inputs: .",
+      },
+      {
+        template: "Updated inputs: {{ space_separated_dirs }}",
+        dirs: ["subflake", "subflake2"],
+        expected: "Updated inputs: subflake subflake2",
+      },
+      {
+        template: "Updated inputs:\n{{ updated_dirs_list }}",
+        dirs: ["flake1", "flake2"],
+        expected: `Updated inputs:\n* flake1\n* flake2`,
+      },
+    ];
 
-    testCases.forEach(({ template, expected }) => {
-      expect(renderPullRequestBody(template)).toEqual(expected);
+    testCases.forEach(({ template, dirs, expected }) => {
+      expect(renderPullRequestBody(template, dirs)).toEqual(expected);
     });
   });
 });

src/template.ts

@@ -1,8 +1,23 @@
 import Handlebars from "handlebars";
 
-export function renderPullRequestBody(template: string): string {
+export function renderPullRequestBody(
+  template: string,
+  dirs: string[],
+): string {
+  const commaSeparated = dirs.join(", ");
+  const spaceSeparated = dirs.join(" ");
+  const dirsList = dirs.map((d: string) => `* ${d}`).join("\n");
+
   const tpl = Handlebars.compile(template);
-  return tpl({});
+
+  return tpl({
+    // eslint-disable-next-line camelcase
+    comma_separated_dirs: commaSeparated,
+    // eslint-disable-next-line camelcase
+    space_separated_dirs: spaceSeparated,
+    // eslint-disable-next-line camelcase
+    updated_dirs_list: dirsList,
+  });
 }
 
 export function renderCommitMessage(
@@ -11,7 +26,9 @@ export function renderCommitMessage(
   flakeDotLock: string,
 ): string {
   return render(template, {
+    // eslint-disable-next-line camelcase
     flake_dot_lock_dir: flakeDotLockDir,
+    // eslint-disable-next-line camelcase
     flake_dot_lock: flakeDotLock,
   });
 }