From 2ffa10a09aa0ba7b6b01868336ffda67b288b3d1 Mon Sep 17 00:00:00 2001
From: Ivan Goncharov <ivan.goncharov.ua@gmail.com>
Date: Tue, 15 Oct 2019 17:17:04 +0300
Subject: [PATCH] gen-changelog: add support for rebased PRs (#2220)

---
 resources/gen-changelog.js | 126 +++++++++++++++++++++++--------------
 1 file changed, 80 insertions(+), 46 deletions(-)

diff --git a/resources/gen-changelog.js b/resources/gen-changelog.js
index 2670f32f60..d29dd17bd9 100644
--- a/resources/gen-changelog.js
+++ b/resources/gen-changelog.js
@@ -47,14 +47,14 @@ if (!packageJSON.repository || typeof packageJSON.repository.url !== 'string') {
   process.exit(1);
 }
 
-const match = /https:\/\/github.com\/([^/]+)\/([^/]+).git/.exec(
+const repoURLMatch = /https:\/\/github.com\/([^/]+)\/([^/]+).git/.exec(
   packageJSON.repository.url,
 );
-if (match == null) {
+if (repoURLMatch == null) {
   console.error('Cannot extract organisation and repo name from repo URL!');
   process.exit(1);
 }
-const [, githubOrg, githubRepo] = match;
+const [, githubOrg, githubRepo] = repoURLMatch;
 
 getChangeLog()
   .then(changelog => process.stdout.write(changelog))
@@ -73,22 +73,35 @@ function getChangeLog() {
   }
 
   const date = exec('git log -1 --format=%cd --date=short');
-  return getCommitsInfo(commitsList.split('\n')).then(commitsInfo =>
-    genChangeLog(tag, date, commitsInfo),
-  );
+  return getCommitsInfo(commitsList.split('\n'))
+    .then(commitsInfo => getPRsInfo(commitsInfoToPRs(commitsInfo)))
+    .then(prsInfo => genChangeLog(tag, date, prsInfo));
 }
 
-function genChangeLog(tag, date, commitsInfo) {
-  const allPRs = commitsInfoToPRs(commitsInfo);
+function genChangeLog(tag, date, allPRs) {
   const byLabel = {};
   const commitersByLogin = {};
 
   for (const pr of allPRs) {
-    if (!labelsConfig[pr.label]) {
-      throw new Error('Unknown label: ' + pr.label + pr.number);
+    const labels = pr.labels.nodes
+      .map(label => label.name)
+      .filter(label => label.startsWith('PR: '));
+
+    if (labels.length === 0) {
+      throw new Error(`PR #${pr.number} missing label`);
     }
-    byLabel[pr.label] = byLabel[pr.label] || [];
-    byLabel[pr.label].push(pr);
+    if (labels.length > 1) {
+      throw new Error(
+        `PR #${pr.number} has conflicting labels: ` + labels.join('\n'),
+      );
+    }
+
+    const label = labels[0];
+    if (!labelsConfig[label]) {
+      throw new Error('Unknown label: ' + label + pr.number);
+    }
+    byLabel[label] = byLabel[label] || [];
+    byLabel[label].push(pr);
     commitersByLogin[pr.author.login] = pr.author;
   }
 
@@ -188,23 +201,9 @@ async function batchCommitInfo(commits) {
             associatedPullRequests(first: 10) {
               nodes {
                 number
-                title
-                url
-                author {
-                  login
-                  url
-                  ... on User {
-                    name
-                  }
-                }
                 repository {
                   nameWithOwner
                 }
-                labels(first: 10) {
-                  nodes {
-                    name
-                  }
-                }
               }
             }
           }
@@ -227,6 +226,45 @@ async function batchCommitInfo(commits) {
   return commitsInfo;
 }
 
+async function batchPRInfo(prs) {
+  let prsSubQuery = '';
+  for (const number of prs) {
+    prsSubQuery += `
+        pr_${number}: pullRequest(number: ${number}) {
+          number
+          title
+          url
+          author {
+            login
+            url
+            ... on User {
+              name
+            }
+          }
+          labels(first: 10) {
+            nodes {
+              name
+            }
+          }
+        }
+    `;
+  }
+
+  const response = await graphqlRequest(`
+    {
+      repository(owner: "${githubOrg}", name: "${githubRepo}") {
+        ${prsSubQuery}
+      }
+    }
+  `);
+
+  const prsInfo = [];
+  for (const number of prs) {
+    prsInfo.push(response.repository['pr_' + number]);
+  }
+  return prsInfo;
+}
+
 function commitsInfoToPRs(commits) {
   const prs = {};
   for (const commit of commits) {
@@ -234,6 +272,11 @@ function commitsInfoToPRs(commits) {
       pr => pr.repository.nameWithOwner === `${githubOrg}/${githubRepo}`,
     );
     if (associatedPRs.length === 0) {
+      const match = / \(#([0-9]+)\)$/m.exec(commit.message);
+      if (match) {
+        prs[parseInt(match[1], 10)] = true;
+        continue;
+      }
       throw new Error(
         `Commit ${commit.oid} has no associated PR: ${commit.message}`,
       );
@@ -244,30 +287,21 @@ function commitsInfoToPRs(commits) {
       );
     }
 
-    const pr = associatedPRs[0];
-    const labels = pr.labels.nodes
-      .map(label => label.name)
-      .filter(label => label.startsWith('PR: '));
+    prs[associatedPRs[0].number] = true;
+  }
 
-    if (labels.length === 0) {
-      throw new Error(`PR #${pr.number} missing label`);
-    }
-    if (labels.length > 1) {
-      throw new Error(
-        `PR #${pr.number} has conflicting labels: ` + labels.join('\n'),
-      );
-    }
+  return Object.keys(prs);
+}
 
-    prs[pr.number] = {
-      number: pr.number,
-      title: pr.title,
-      url: pr.url,
-      author: pr.author,
-      label: labels[0],
-    };
+async function getPRsInfo(commits) {
+  // Split pr into batches of 50 to prevent timeouts
+  const prInfoPromises = [];
+  for (let i = 0; i < commits.length; i += 50) {
+    const batch = commits.slice(i, i + 50);
+    prInfoPromises.push(batchPRInfo(batch));
   }
 
-  return Object.values(prs);
+  return (await Promise.all(prInfoPromises)).flat();
 }
 
 async function getCommitsInfo(commits) {