Try to recover from compareCommits timeout from GitHub (#6654)

Part of #6513

Author: alexr00

src/github/loggingOctokit.ts

@@ -7,9 +7,13 @@ import { Octokit } from '@octokit/rest';
 import { ApolloClient, ApolloQueryResult, FetchResult, MutationOptions, NormalizedCacheObject, OperationVariables, QueryOptions } from 'apollo-boost';
 import { bulkhead, BulkheadPolicy } from 'cockatiel';
 import * as vscode from 'vscode';
+import { GitHubRef } from '../common/githubRef';
 import Logger from '../common/logger';
+import { GitHubRemote } from '../common/remote';
 import { ITelemetry } from '../common/telemetry';
 import { RateLimit } from './graphql';
+import { IRawFileChange } from './interface';
+import { restPaginate } from './utils';
 
 interface RestResponse {
 	headers: {
@@ -139,3 +143,47 @@ export class LoggingOctokit {
 		return result;
 	}
 }
+
+export async function compareCommits(remote: GitHubRemote, octokit: LoggingOctokit, base: GitHubRef, head: GitHubRef, compareWithBaseRef: string, prNumber: number, logId: string): Promise<{ mergeBaseSha: string; files: IRawFileChange[] }> {
+	Logger.debug(`Comparing commits for ${remote.owner}/${remote.repositoryName} with base ${base.repositoryCloneUrl.owner}:${compareWithBaseRef} and head ${head.repositoryCloneUrl.owner}:${head.sha}`, logId);
+	let files: IRawFileChange[] | undefined;
+	let mergeBaseSha: string | undefined;
+
+	const listFiles = async (perPage?: number) => {
+		return restPaginate<typeof octokit.api.pulls.listFiles, IRawFileChange>(octokit.api.pulls.listFiles, {
+			owner: base.repositoryCloneUrl.owner,
+			pull_number: prNumber,
+			repo: remote.repositoryName,
+		}, perPage);
+	};
+
+	try {
+		const { data } = await octokit.call(octokit.api.repos.compareCommits, {
+			repo: remote.repositoryName,
+			owner: remote.owner,
+			base: `${base.repositoryCloneUrl.owner}:${compareWithBaseRef}`,
+			head: `${head.repositoryCloneUrl.owner}:${head.sha}`,
+		});
+		const MAX_FILE_CHANGES_IN_COMPARE_COMMITS = 100;
+
+		if (data.files && data.files.length >= MAX_FILE_CHANGES_IN_COMPARE_COMMITS) {
+			// compareCommits will return a maximum of 100 changed files
+			// If we have (maybe) more than that, we'll need to fetch them with listFiles API call
+			Logger.appendLine(`More than ${MAX_FILE_CHANGES_IN_COMPARE_COMMITS} files changed in #${prNumber}`, logId);
+			files = await listFiles();
+		} else {
+			// if we're under the limit, just use the result from compareCommits, don't make additional API calls.
+			files = data.files ? data.files as IRawFileChange[] : [];
+		}
+		mergeBaseSha = data.merge_base_commit.sha;
+	} catch (e) {
+		if (e.message === 'Server Error') {
+			// Happens when github times out. Let's try to get a few at a time.
+			files = await listFiles(3);
+			mergeBaseSha = base.sha;
+		} else {
+			throw e;
+		}
+	}
+	return { mergeBaseSha, files };
+}

src/github/pullRequestModel.ts

@@ -70,6 +70,7 @@ import {
 	ReviewEvent,
 } from './interface';
 import { IssueModel } from './issueModel';
+import { compareCommits } from './loggingOctokit';
 import {
 	convertRESTPullRequestToRawPullRequest,
 	convertRESTReviewEvent,
@@ -1451,32 +1452,8 @@ export class PullRequestModel extends IssueModel<PullRequest> implements IPullRe
 		}
 
 		Logger.debug(`Comparing commits for ${remote.owner}/${remote.repositoryName} with base ${this.base.repositoryCloneUrl.owner}:${compareWithBaseRef} and head ${this.head!.repositoryCloneUrl.owner}:${this.head!.sha}`, PullRequestModel.ID);
-		const { data } = await octokit.call(octokit.api.repos.compareCommits, {
-			repo: remote.repositoryName,
-			owner: remote.owner,
-			base: `${this.base.repositoryCloneUrl.owner}:${compareWithBaseRef}`,
-			head: `${this.head!.repositoryCloneUrl.owner}:${this.head!.sha}`,
-		});
-
-		this.mergeBase = data.merge_base_commit.sha;
-
-		const MAX_FILE_CHANGES_IN_COMPARE_COMMITS = 100;
-		let files: IRawFileChange[] = [];
-
-		if (data.files && data.files.length >= MAX_FILE_CHANGES_IN_COMPARE_COMMITS) {
-			// compareCommits will return a maximum of 100 changed files
-			// If we have (maybe) more than that, we'll need to fetch them with listFiles API call
-			Logger.appendLine(
-				`More than ${MAX_FILE_CHANGES_IN_COMPARE_COMMITS} files changed in #${this.number}`, PullRequestModel.ID);
-			files = await restPaginate<typeof octokit.api.pulls.listFiles, IRawFileChange>(octokit.api.pulls.listFiles, {
-				owner: this.base.repositoryCloneUrl.owner,
-				pull_number: this.number,
-				repo: remote.repositoryName,
-			});
-		} else {
-			// if we're under the limit, just use the result from compareCommits, don't make additional API calls.
-			files = data.files ? data.files as IRawFileChange[] : [];
-		}
+		const { files, mergeBaseSha } = await compareCommits(remote, octokit, this.base, this.head!, compareWithBaseRef, this.number, PullRequestModel.ID);
+		this.mergeBase = mergeBaseSha;
 
 		if (oldHasChangesSinceReview !== undefined && oldHasChangesSinceReview !== this.hasChangesSinceLastReview && this.hasChangesSinceLastReview && this._showChangesSinceReview) {
 			this._onDidChangeChangesSinceReview.fire();

src/github/utils.ts

@@ -1135,7 +1135,7 @@ export function getReactionGroup(): { title: string; label: string; icon?: vscod
 	return ret;
 }
 
-export async function restPaginate<R extends OctokitTypes.RequestInterface, T>(request: R, variables: Parameters<R>[0]): Promise<T[]> {
+export async function restPaginate<R extends OctokitTypes.RequestInterface, T>(request: R, variables: Parameters<R>[0], per_page: number = 100): Promise<T[]> {
 	let page = 1;
 	let results: T[] = [];
 	let hasNextPage = false;
@@ -1144,7 +1144,7 @@ export async function restPaginate<R extends OctokitTypes.RequestInterface, T>(r
 		const result = await request(
 			{
 				...(variables as any),
-				per_page: 100,
+				per_page,
 				page
 			}
 		);