[ci] Tell too-big PR authors that review waits until the PR is under the cap (#20543)

.github/scripts/auto-label-pr/reviews.js

@@ -42,8 +42,8 @@ function generateReviewMessages(finalLabels, originalLabelCount, deprecatedInfo,
     let message = `${TOO_BIG_MARKER}\n### 📦 Pull Request Size\n\n`;
 
     message +=
-      `Hey @${prAuthor}, thanks for the contribution! Just a heads up, ` +
-      `this PR is on the large side `;
+      `Hey @${prAuthor}, thanks for the contribution. This PR is on the ` +
+      `large side `;
 
     if (tooManyLabels && tooManyChanges) {
       message +=
@@ -57,16 +57,31 @@ function generateReviewMessages(finalLabels, originalLabelCount, deprecatedInfo,
     }
 
     message += `, which makes it harder for maintainers to review.\n\n`;
+    let condition;
+    if (tooManyLabels && tooManyChanges) {
+      condition =
+        `is at most ${TOO_BIG_THRESHOLD} lines (excluding tests) and touches ` +
+        `at most ${MAX_LABELS} components/areas`;
+    } else if (tooManyLabels) {
+      condition = `touches at most ${MAX_LABELS} components/areas`;
+    } else {
+      condition = `is at most ${TOO_BIG_THRESHOLD} lines (excluding tests)`;
+    }
     message +=
-      `Smaller, focused PRs tend to be reviewed much faster since they ` +
-      `fit into the short gaps between other maintainer work; large ones ` +
-      `often have to wait for a rare long uninterrupted block of time. ` +
-      `If you can break this up into smaller pieces that can be reviewed ` +
-      `independently, it will almost certainly land faster overall.\n\n`;
+      `**This PR will not be reviewed until it ${condition}.** We know ` +
+      `that is not what you want to hear after this much work, and we want ` +
+      `to be upfront so you do not wait for a review that is not coming: ` +
+      `please split the change. The label is removed automatically once ` +
+      `the PR ${condition}.\n\n`;
     message +=
-      `Before putting more time in, it's also worth popping into ` +
-      `\`#devs\` on [Discord](https://esphome.io/chat) so we can help ` +
-      `you scope things and flag anything already in flight.\n\n`;
+      `There is no exception you can request. Rarely, a maintainer agrees in ` +
+      `\`#devs\` on [Discord](https://esphome.io/chat) to review a change that ` +
+      `genuinely cannot be split as one piece and adds the \`mega-pr\` label, ` +
+      `but that is rare enough that you should plan on splitting rather than ` +
+      `wait for it. Smaller, focused PRs are picked up much faster because ` +
+      `they fit into the short gaps between other maintainer work. For a new ` +
+      `component, the first PR brings the hub and a single platform (for ` +
+      `example \`sensor\`); each further platform is its own PR on top of it.\n\n`;
     message +=
       `For more details (including how to split the work up), see: ` +
       `https://developers.esphome.io/contributing/submitting-your-work/` +
@@ -214,6 +229,7 @@ async function handleMaintainerAccessComment(github, context, maintainerAccess)
 }
 
 module.exports = {
+  generateReviewMessages,
   handleReviews,
   handleMaintainerAccessComment
 };

.github/scripts/auto-label-pr/tests/reviews.test.js

@@ -0,0 +1,38 @@
+const { describe, it } = require('node:test');
+const assert = require('node:assert/strict');
+const { generateReviewMessages } = require('../reviews');
+
+const MAX_LABELS = 15;
+const TOO_BIG_THRESHOLD = 1000;
+
+function tooBigMessage(labelCount, additions) {
+  const files = [{ filename: 'esphome/components/a/a.cpp', additions, deletions: 0 }];
+  const messages = generateReviewMessages(['too-big'], labelCount, null, files, additions, 0, 'someone', MAX_LABELS, TOO_BIG_THRESHOLD);
+  assert.equal(messages.length, 1);
+  return messages[0];
+}
+
+describe('too-big review message', () => {
+  it('names the line cap when the PR is too long', () => {
+    const message = tooBigMessage(3, 1500);
+    assert.match(message, /will not be reviewed until it is at most 1000 lines \(excluding tests\)\./);
+    assert.match(message, /removed automatically once the PR is at most 1000 lines/);
+    assert.doesNotMatch(message, /components\/areas\./);
+  });
+
+  it('names the area cap when the PR touches too many areas but is short', () => {
+    const message = tooBigMessage(20, 200);
+    assert.match(message, /will not be reviewed until it touches at most 15 components\/areas\./);
+    assert.doesNotMatch(message, /until it is at most 1000 lines/);
+  });
+
+  it('names both caps when both are exceeded', () => {
+    const message = tooBigMessage(20, 1500);
+    assert.match(message, /is at most 1000 lines \(excluding tests\) and touches at most 15 components\/areas\./);
+  });
+
+  it('tells new-component authors to bring one platform first', () => {
+    assert.match(tooBigMessage(3, 1500), /hub and a single platform/);
+    assert.match(tooBigMessage(3, 1500), /mega-pr/);
+  });
+});