app_dart/lib/src/request_handlers/flaky_handler_utils.dart - mirrors/cocoon - Git at Google

 // Copyright 2019 The Flutter Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.

 import 'dart:convert';
 import 'dart:core';

 import 'package:cocoon_service/ci_yaml.dart';
 import 'package:cocoon_service/src/request_handlers/test_ownership.dart';
 import 'package:collection/collection.dart';
 import 'package:github/github.dart';

 import '../service/bigquery.dart';
 import '../service/github_service.dart';
 import '../../protos.dart' as pb;

 // String constants.
 const String kFlakeLabel = 'c: flake';
 const String kFrameworkLabel = 'team-framework';
 const String kToolLabel = 'team-tool';
 const String kEngineLabel = 'team-engine';
 const String kWebLabel = 'team-web';
 const String kInfraLabel = 'team-infra';
 const String kAndroidLabel = 'team-android';
 const String kIosLabel = 'team-ios';
 const String kReleaseLabel = 'team-release';
 const String kEcosystemLabel = 'team-ecosystem';
 const String kP0Label = 'P0';
 const String kP1Label = 'P1';
 const String kP2Label = 'P2';
 const String kP3Label = 'P3';

 const String kBigQueryProjectId = 'flutter-dashboard';
 const String kCiYamlTargetsKey = 'targets';
 const String kCiYamlTargetNameKey = 'name';
 const String kCiYamlTargetIgnoreFlakiness = 'ignore_flakiness';
 const String kCiYamlTargetIsFlakyKey = 'bringup';
 const String kCiYamlPropertiesKey = 'properties';
 const String kCiYamlTargetTagsKey = 'tags';
 const String kCiYamlTargetTagsShard = 'shard';
 const String kCiYamlTargetTagsFirebaselab = 'firebaselab';
 const String kCiYamlTargetTagsDevicelab = 'devicelab';
 const String kCiYamlTargetTagsFramework = 'framework';
 const String kCiYamlTargetTagsHostonly = 'hostonly';

 const String kMasterRefs = 'heads/master';
 const String kModifyMode = '100644'; // This is equivalent to mode: `-rw-r--r--`.
 const String kModifyType = 'blob';

 const int kSuccessBuildNumberLimit = 3;
 const int kFlayRatioBuildNumberList = 10;
 const double kDefaultFlakyRatioThreshold = 0.02;
 const int kGracePeriodForClosedFlake = 15; // days

 const String _commitPrefix = 'https://github.com/flutter/flutter/commit/';
 const String _buildDashboardPrefix = 'https://flutter-dashboard.appspot.com/#/build';
 const String _prodBuildPrefix = 'https://ci.chromium.org/ui/p/flutter/builders/prod/';
 const String _stagingBuildPrefix = 'https://ci.chromium.org/ui/p/flutter/builders/staging/';
 const String _flakeRecordPrefix =
     'https://data.corp.google.com/sites/flutter_infra_metrics_datasite/flutter_check_test_flakiness_status_dashboard/?p=BUILDER_NAME:';

 /// A builder to build a new issue for a flake.
 class IssueBuilder {
   IssueBuilder({
     required this.statistic,
     required this.ownership,
     required this.threshold,
     this.bringup = false,
   });

   final BuilderStatistic statistic;
   final TestOwnership ownership;
   final double threshold;
   final bool bringup;

   Bucket get buildBucket {
     return bringup ? Bucket.staging : Bucket.prod;
   }

   String get issueTitle {
     return '${statistic.name} is ${_formatRate(statistic.flakyRate)}% flaky';
   }

   String? get issueAssignee {
     return ownership.owner;
   }

   /// Return `kSuccessBuildNumberLimit` successful builds if there are more. Otherwise return what's available.
   int numberOfSuccessBuilds(int numberOfAvailableSuccessBuilds) {
     return numberOfAvailableSuccessBuilds >= kSuccessBuildNumberLimit
         ? kSuccessBuildNumberLimit
         : numberOfAvailableSuccessBuilds;
   }

   String get issueBody {
     return '''
 ${_buildHiddenMetaTags(name: statistic.name)}
 ${_issueSummary(statistic, threshold, bringup)}

 One recent flaky example for a same commit: ${_issueBuildLink(builder: statistic.name, build: statistic.flakyBuildOfRecentCommit, bucket: buildBucket)}
 Commit: $_commitPrefix${statistic.recentCommit}

 Flaky builds:
 ${_issueBuildLinks(builder: statistic.name, builds: statistic.flakyBuilds!, bucket: buildBucket)}

 Recent test runs:
 ${_issueBuilderLink(statistic.name)}

 Please follow https://github.com/flutter/flutter/wiki/Reducing-Test-Flakiness#fixing-flaky-tests to fix the flakiness and enable the test back after validating the fix (internal dashboard to validate: go/flutter_test_flakiness).
 ''';
   }

   List<String> get issueLabels {
     final List<String> labels = <String>[
       kFlakeLabel,
       kP0Label,
     ];
     final String? teamLabel = getTeamLabelFromTeam(ownership.team);
     if (teamLabel != null && teamLabel.isNotEmpty == true) {
       labels.add(teamLabel);
     }
     return labels;
   }
 }

 /// A builder to build the update comment and labels for an existing open flaky
 /// issue.
 class IssueUpdateBuilder {
   IssueUpdateBuilder({
     required this.statistic,
     required this.threshold,
     required this.existingIssue,
     required this.bucket,
   });

   final BuilderStatistic statistic;
   final double threshold;
   final Issue existingIssue;
   final Bucket bucket;

   bool get isBelow => statistic.flakyRate < threshold;

   String get bucketString => bucket.toString().split('.').last;

   List<String> get issueLabels {
     final List<String> existingLabels = existingIssue.labels.map<String>((IssueLabel label) => label.name).toList();
     // Update the priority.
     if (!existingLabels.contains(kP0Label) && !isBelow) {
       existingLabels.add(kP0Label);
       existingLabels.remove(kP1Label);
       existingLabels.remove(kP2Label);
       existingLabels.remove(kP3Label);
     }
     return existingLabels;
   }

   String get issueUpdateComment {
     String result =
         '[$bucketString pool] flaky ratio for the past (up to) 100 commits between ${statistic.fromDate} and ${statistic.toDate} is ${_formatRate(statistic.flakyRate)}%. Flaky number: ${statistic.flakyNumber}; total number: ${statistic.totalNumber}.\n';
     if (statistic.flakyRate > 0.0) {
       result += '''
 One recent flaky example for a same commit: ${_issueBuildLink(builder: statistic.name, build: statistic.flakyBuildOfRecentCommit, bucket: bucket)}
 Commit: $_commitPrefix${statistic.recentCommit}
 Flaky builds:
 ${_issueBuildLinks(builder: statistic.name, builds: statistic.flakyBuilds!, bucket: bucket)}

 Recent test runs:
 ${_issueBuilderLink(statistic.name)}
 ''';
     }
     return result;
   }
 }

 /// A builder to build the pull request title and body for marking test flaky
 class PullRequestBuilder {
   PullRequestBuilder({
     required this.statistic,
     required this.ownership,
     required this.issue,
   });

   final BuilderStatistic statistic;
   final TestOwnership ownership;
   final Issue issue;

   String get pullRequestTitle => 'Marks ${statistic.name} to be flaky';
   String get pullRequestBody => '${_buildHiddenMetaTags(name: statistic.name)}Issue link: ${issue.htmlUrl}\n';
   String? get pullRequestReviewer => ownership.owner;
 }

 /// A builder to build the pull request title and body for marking test unflaky
 class DeflakePullRequestBuilder {
   DeflakePullRequestBuilder({
     required this.name,
     required this.recordNumber,
     required this.ownership,
     this.issue,
   });

   final String? name;
   final Issue? issue;
   final TestOwnership ownership;
   final int recordNumber;

   String get pullRequestTitle => 'Marks $name to be unflaky';
   String get pullRequestBody {
     String body = _buildHiddenMetaTags(name: name);
     if (issue != null) {
       body +=
           'The issue ${issue!.htmlUrl} has been closed, and the test has been passing for [$recordNumber consecutive runs](${Uri.encodeFull('$_flakeRecordPrefix"$name"')}).\n';
     } else {
       body +=
           'The test has been passing for [$recordNumber consecutive runs](${Uri.encodeFull('$_flakeRecordPrefix"$name"')}).\n';
     }
     body += 'This test can be marked as unflaky.\n';
     return body;
   }

   String? get pullRequestReviewer => ownership.owner;
 }

 // TESTOWNER Regex

 const String kOwnerGroupName = 'owners';
 final RegExp devicelabTestOwners =
     RegExp('## Linux Android DeviceLab tests\n(?<$kOwnerGroupName>.+)## Host only framework tests', dotAll: true);
 final RegExp frameworkHostOnlyTestOwners =
     RegExp('## Host only framework tests\n(?<$kOwnerGroupName>.+)## Firebase tests', dotAll: true);
 final RegExp firebaselabTestOwners = RegExp('## Firebase tests\n(?<$kOwnerGroupName>.+)## Shards tests', dotAll: true);
 final RegExp shardTestOwners = RegExp('## Shards tests\n(?<$kOwnerGroupName>.+)', dotAll: true);

 // Utils methods

 /// Gets the existing flaky issues.
 ///
 /// The state can be 'open', 'closed', or 'all'.
 Future<Map<String?, Issue>> getExistingIssues(GithubService gitHub, RepositorySlug slug, {String state = 'all'}) async {
   final Map<String?, Issue> nameToExistingIssue = <String?, Issue>{};
   for (final Issue issue in await gitHub.listIssues(slug, state: state, labels: <String>[kFlakeLabel])) {
     if (issue.htmlUrl.contains('pull') == true) {
       // For some reason, this github api may also return pull requests.
       continue;
     }
     final Map<String, dynamic>? metaTags = retrieveMetaTagsFromContent(issue.body);
     if (metaTags != null) {
       final String? name = metaTags['name'] as String?;
       if (!nameToExistingIssue.containsKey(name) || _isOtherIssueMoreImportant(nameToExistingIssue[name]!, issue)) {
         nameToExistingIssue[name] = issue;
       }
     }
   }
   return nameToExistingIssue;
 }

 /// Gets the existing open pull requests that make tests flaky.
 Future<Map<String?, PullRequest>> getExistingPRs(GithubService gitHub, RepositorySlug slug) async {
   final Map<String?, PullRequest> nameToExistingPRs = <String?, PullRequest>{};
   for (final PullRequest pr in await gitHub.listPullRequests(slug, null)) {
     try {
       if (pr.body == null) {
         continue;
       }
       final Map<String, dynamic>? metaTags = retrieveMetaTagsFromContent(pr.body!);
       if (metaTags != null) {
         nameToExistingPRs[metaTags['name'] as String] = pr;
       }
     } catch (e) {
       throw 'Unable to parse body of ${pr.htmlUrl}\n$e';
     }
   }
   return nameToExistingPRs;
 }

 /// File a GitHub flaky issue based on builder details in recent prod/staging runs.
 Future<Issue> fileFlakyIssue({
   required BuilderDetail builderDetail,
   required GithubService gitHub,
   required RepositorySlug slug,
   double threshold = kDefaultFlakyRatioThreshold,
   bool bringup = false,
 }) async {
   final IssueBuilder issueBuilder = IssueBuilder(
     statistic: builderDetail.statistic,
     ownership: builderDetail.ownership,
     threshold: kDefaultFlakyRatioThreshold,
     bringup: bringup,
   );
   return gitHub.createIssue(
     slug,
     title: issueBuilder.issueTitle,
     body: issueBuilder.issueBody,
     labels: issueBuilder.issueLabels,
     assignee: issueBuilder.issueAssignee,
   );
 }

 /// Looks up the owner of a builder in TESTOWNERS file.
 TestOwnership getTestOwnership(pb.Target target, BuilderType type, String testOwnersContent) {
   final TestOwner testOwner = TestOwner(type);
   return testOwner.getTestOwnership(target, testOwnersContent);
 }

 /// Gets the [BuilderType] of the builder by looking up the information in the
 /// ci.yaml.
 BuilderType getTypeForBuilder(String? targetName, CiYaml ciYaml, {bool unfilteredTargets = false}) {
   final List<String>? tags = _getTags(targetName, ciYaml, unfilteredTargets: unfilteredTargets);
   if (tags == null || tags.isEmpty) {
     return BuilderType.unknown;
   }

   bool hasFrameworkTag = false;
   bool hasHostOnlyTag = false;
   // If tags contain 'shard', it must be a shard test.
   // If tags contain 'devicelab', it must be a devicelab test.
   // If tags contain 'firebaselab`, it must be a firebase tests.
   // Otherwise, it is framework host only test if its tags contain both
   // 'framework' and 'hostonly'.
   for (String tag in tags) {
     if (tag == kCiYamlTargetTagsFirebaselab) {
       return BuilderType.firebaselab;
     } else if (tag == kCiYamlTargetTagsShard) {
       return BuilderType.shard;
     } else if (tag == kCiYamlTargetTagsDevicelab) {
       return BuilderType.devicelab;
     } else if (tag == kCiYamlTargetTagsFramework) {
       hasFrameworkTag = true;
     } else if (tag == kCiYamlTargetTagsHostonly) {
       hasHostOnlyTag = true;
     }
   }
   return hasFrameworkTag && hasHostOnlyTag ? BuilderType.frameworkHostOnly : BuilderType.unknown;
 }

 List<String>? _getTags(String? targetName, CiYaml ciYaml, {bool unfilteredTargets = false}) {
   final Set<Target> allUniqueTargets = {};
   if (!unfilteredTargets) {
     allUniqueTargets.addAll(ciYaml.presubmitTargets);
     allUniqueTargets.addAll(ciYaml.postsubmitTargets);
   } else {
     allUniqueTargets.addAll(ciYaml.targets);
   }

   final Target? target = allUniqueTargets.firstWhereOrNull((element) => element.value.name == targetName);
   return target?.tags;
 }

 bool _isOtherIssueMoreImportant(Issue original, Issue other) {
   // Open issues are always more important than closed issues. If both issue
   // are closed, the one that is most recently created is more important.
   if (original.isOpen && other.isOpen) {
     throw 'There should not be two open issues for the same test';
   } else if (original.isOpen && other.isClosed) {
     return false;
   } else if (original.isClosed && other.isOpen) {
     return true;
   } else {
     return other.createdAt!.isAfter(original.createdAt!);
   }
 }

 String _buildHiddenMetaTags({String? name}) {
   return '''<!-- meta-tags: To be used by the automation script only, DO NOT MODIFY.
 {
   "name": "$name"
 }
 -->
 ''';
 }

 final RegExp _issueHiddenMetaTagsRegex =
     RegExp(r'<!-- meta-tags: To be used by the automation script only, DO NOT MODIFY\.(?<meta>.+)-->', dotAll: true);

 /// Checks whether the github content contains meta tags and returns the meta
 /// tags if it does.
 ///
 /// The script generated contents for issue bodies or pull request bodies
 /// contain the meta tags. Using this method is a reliable way to check whether
 /// a issue or pull request is generated by this script.
 Map<String, dynamic>? retrieveMetaTagsFromContent(String content) {
   final RegExpMatch? match = _issueHiddenMetaTagsRegex.firstMatch(content);
   if (match == null) {
     return null;
   }
   return jsonDecode(match.namedGroup('meta')!) as Map<String, dynamic>?;
 }

 String _formatRate(double rate) => (rate * 100).toStringAsFixed(2);

 String _issueBuildLinks({String? builder, required List<String> builds, Bucket bucket = Bucket.prod}) {
   return builds.map((String build) => _issueBuildLink(builder: builder, build: build, bucket: bucket)).join('\n');
 }

 String _issueSummary(BuilderStatistic statistic, double threshold, bool bringup) {
   final String summary;
   if (bringup) {
     summary =
         'The post-submit test builder `${statistic.name}`, which has been marked `bringup: true`, had ${statistic.flakyNumber} flakes over past ${statistic.totalNumber} commits.';
   } else {
     summary =
         'The post-submit test builder `${statistic.name}` had a flaky ratio ${_formatRate(statistic.flakyRate)}% for the past (up to) 100 commits, which is above our ${_formatRate(threshold)}% threshold.';
   }
   return summary;
 }

 String _issueBuildLink({String? builder, String? build, Bucket bucket = Bucket.prod}) {
   final String buildPrefix = bucket == Bucket.staging ? _stagingBuildPrefix : _prodBuildPrefix;
   return Uri.encodeFull('$buildPrefix$builder/$build');
 }

 String _issueBuilderLink(String? builder) {
   return Uri.encodeFull('$_buildDashboardPrefix?taskFilter=$builder');
 }

 String? getTeamLabelFromTeam(Team? team) {
   return switch (team) {
     Team.framework => kFrameworkLabel,
     Team.engine => kEngineLabel,
     Team.tool => kToolLabel,
     Team.web => kWebLabel,
     Team.infra => kInfraLabel,
     Team.android => kAndroidLabel,
     Team.ios => kIosLabel,
     Team.release => kReleaseLabel,
     Team.plugins => kEcosystemLabel,
     Team.unknown || null => null,
   };
 }

 enum BuilderType {
   devicelab,
   frameworkHostOnly,
   shard,
   firebaselab,
   unknown,
 }

 enum Bucket {
   prod,
   staging,
 }

 enum Team {
   framework,
   engine,
   tool,
   web,
   infra,
   android,
   ios,
   release,
   plugins,
   unknown,
 }

 class TestOwnership {
   TestOwnership(
     this.owner,
     this.team,
   );
   String? owner;
   Team? team;
 }

 class BuilderDetail {
   const BuilderDetail({
     required this.statistic,
     required this.existingIssue,
     required this.existingPullRequest,
     required this.isMarkedFlaky,
     required this.ownership,
     required this.type,
   });
   final BuilderStatistic statistic;
   final Issue? existingIssue;
   final PullRequest? existingPullRequest;
   final TestOwnership ownership;
   final bool isMarkedFlaky;
   final BuilderType type;
 }
	// Copyright 2019 The Flutter Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style license that can be
	// found in the LICENSE file.

	import 'dart:convert';
	import 'dart:core';

	import 'package:cocoon_service/ci_yaml.dart';
	import 'package:cocoon_service/src/request_handlers/test_ownership.dart';
	import 'package:collection/collection.dart';
	import 'package:github/github.dart';

	import '../service/bigquery.dart';
	import '../service/github_service.dart';
	import '../../protos.dart' as pb;

	// String constants.
	const String kFlakeLabel = 'c: flake';
	const String kFrameworkLabel = 'team-framework';
	const String kToolLabel = 'team-tool';
	const String kEngineLabel = 'team-engine';
	const String kWebLabel = 'team-web';
	const String kInfraLabel = 'team-infra';
	const String kAndroidLabel = 'team-android';
	const String kIosLabel = 'team-ios';
	const String kReleaseLabel = 'team-release';
	const String kEcosystemLabel = 'team-ecosystem';
	const String kP0Label = 'P0';
	const String kP1Label = 'P1';
	const String kP2Label = 'P2';
	const String kP3Label = 'P3';

	const String kBigQueryProjectId = 'flutter-dashboard';
	const String kCiYamlTargetsKey = 'targets';
	const String kCiYamlTargetNameKey = 'name';
	const String kCiYamlTargetIgnoreFlakiness = 'ignore_flakiness';
	const String kCiYamlTargetIsFlakyKey = 'bringup';
	const String kCiYamlPropertiesKey = 'properties';
	const String kCiYamlTargetTagsKey = 'tags';
	const String kCiYamlTargetTagsShard = 'shard';
	const String kCiYamlTargetTagsFirebaselab = 'firebaselab';
	const String kCiYamlTargetTagsDevicelab = 'devicelab';
	const String kCiYamlTargetTagsFramework = 'framework';
	const String kCiYamlTargetTagsHostonly = 'hostonly';

	const String kMasterRefs = 'heads/master';
	const String kModifyMode = '100644'; // This is equivalent to mode: `-rw-r--r--`.
	const String kModifyType = 'blob';

	const int kSuccessBuildNumberLimit = 3;
	const int kFlayRatioBuildNumberList = 10;
	const double kDefaultFlakyRatioThreshold = 0.02;
	const int kGracePeriodForClosedFlake = 15; // days

	const String _commitPrefix = 'https://github.com/flutter/flutter/commit/';
	const String _buildDashboardPrefix = 'https://flutter-dashboard.appspot.com/#/build';
	const String _prodBuildPrefix = 'https://ci.chromium.org/ui/p/flutter/builders/prod/';
	const String _stagingBuildPrefix = 'https://ci.chromium.org/ui/p/flutter/builders/staging/';
	const String _flakeRecordPrefix =
	'https://data.corp.google.com/sites/flutter_infra_metrics_datasite/flutter_check_test_flakiness_status_dashboard/?p=BUILDER_NAME:';

	/// A builder to build a new issue for a flake.
	class IssueBuilder {
	IssueBuilder({
	required this.statistic,
	required this.ownership,
	required this.threshold,
	this.bringup = false,
	});

	final BuilderStatistic statistic;
	final TestOwnership ownership;
	final double threshold;
	final bool bringup;

	Bucket get buildBucket {
	return bringup ? Bucket.staging : Bucket.prod;
	}

	String get issueTitle {
	return '${statistic.name} is ${_formatRate(statistic.flakyRate)}% flaky';
	}

	String? get issueAssignee {
	return ownership.owner;
	}

	/// Return `kSuccessBuildNumberLimit` successful builds if there are more. Otherwise return what's available.
	int numberOfSuccessBuilds(int numberOfAvailableSuccessBuilds) {
	return numberOfAvailableSuccessBuilds >= kSuccessBuildNumberLimit
	? kSuccessBuildNumberLimit
	: numberOfAvailableSuccessBuilds;
	}

	String get issueBody {
	return '''
	${_buildHiddenMetaTags(name: statistic.name)}
	${_issueSummary(statistic, threshold, bringup)}

	One recent flaky example for a same commit: ${_issueBuildLink(builder: statistic.name, build: statistic.flakyBuildOfRecentCommit, bucket: buildBucket)}
	Commit: $_commitPrefix${statistic.recentCommit}

	Flaky builds:
	${_issueBuildLinks(builder: statistic.name, builds: statistic.flakyBuilds!, bucket: buildBucket)}

	Recent test runs:
	${_issueBuilderLink(statistic.name)}

	Please follow https://github.com/flutter/flutter/wiki/Reducing-Test-Flakiness#fixing-flaky-tests to fix the flakiness and enable the test back after validating the fix (internal dashboard to validate: go/flutter_test_flakiness).
	''';
	}

	List<String> get issueLabels {
	final List<String> labels = <String>[
	kFlakeLabel,
	kP0Label,
	];
	final String? teamLabel = getTeamLabelFromTeam(ownership.team);
	if (teamLabel != null && teamLabel.isNotEmpty == true) {
	labels.add(teamLabel);
	}
	return labels;
	}
	}

	/// A builder to build the update comment and labels for an existing open flaky
	/// issue.
	class IssueUpdateBuilder {
	IssueUpdateBuilder({
	required this.statistic,
	required this.threshold,
	required this.existingIssue,
	required this.bucket,
	});

	final BuilderStatistic statistic;
	final double threshold;
	final Issue existingIssue;
	final Bucket bucket;

	bool get isBelow => statistic.flakyRate < threshold;

	String get bucketString => bucket.toString().split('.').last;

	List<String> get issueLabels {
	final List<String> existingLabels = existingIssue.labels.map<String>((IssueLabel label) => label.name).toList();
	// Update the priority.
	if (!existingLabels.contains(kP0Label) && !isBelow) {
	existingLabels.add(kP0Label);
	existingLabels.remove(kP1Label);
	existingLabels.remove(kP2Label);
	existingLabels.remove(kP3Label);
	}
	return existingLabels;
	}

	String get issueUpdateComment {
	String result =
	'[$bucketString pool] flaky ratio for the past (up to) 100 commits between ${statistic.fromDate} and ${statistic.toDate} is ${_formatRate(statistic.flakyRate)}%. Flaky number: ${statistic.flakyNumber}; total number: ${statistic.totalNumber}.\n';
	if (statistic.flakyRate > 0.0) {
	result += '''
	One recent flaky example for a same commit: ${_issueBuildLink(builder: statistic.name, build: statistic.flakyBuildOfRecentCommit, bucket: bucket)}
	Commit: $_commitPrefix${statistic.recentCommit}
	Flaky builds:
	${_issueBuildLinks(builder: statistic.name, builds: statistic.flakyBuilds!, bucket: bucket)}

	Recent test runs:
	${_issueBuilderLink(statistic.name)}
	''';
	}
	return result;
	}
	}

	/// A builder to build the pull request title and body for marking test flaky
	class PullRequestBuilder {
	PullRequestBuilder({
	required this.statistic,
	required this.ownership,
	required this.issue,
	});

	final BuilderStatistic statistic;
	final TestOwnership ownership;
	final Issue issue;

	String get pullRequestTitle => 'Marks ${statistic.name} to be flaky';
	String get pullRequestBody => '${_buildHiddenMetaTags(name: statistic.name)}Issue link: ${issue.htmlUrl}\n';
	String? get pullRequestReviewer => ownership.owner;
	}

	/// A builder to build the pull request title and body for marking test unflaky
	class DeflakePullRequestBuilder {
	DeflakePullRequestBuilder({
	required this.name,
	required this.recordNumber,
	required this.ownership,
	this.issue,
	});

	final String? name;
	final Issue? issue;
	final TestOwnership ownership;
	final int recordNumber;

	String get pullRequestTitle => 'Marks $name to be unflaky';
	String get pullRequestBody {
	String body = _buildHiddenMetaTags(name: name);
	if (issue != null) {
	body +=
	'The issue ${issue!.htmlUrl} has been closed, and the test has been passing for [$recordNumber consecutive runs](${Uri.encodeFull('$_flakeRecordPrefix"$name"')}).\n';
	} else {
	body +=
	'The test has been passing for [$recordNumber consecutive runs](${Uri.encodeFull('$_flakeRecordPrefix"$name"')}).\n';
	}
	body += 'This test can be marked as unflaky.\n';
	return body;
	}

	String? get pullRequestReviewer => ownership.owner;
	}

	// TESTOWNER Regex

	const String kOwnerGroupName = 'owners';
	final RegExp devicelabTestOwners =
	RegExp('## Linux Android DeviceLab tests\n(?<$kOwnerGroupName>.+)## Host only framework tests', dotAll: true);
	final RegExp frameworkHostOnlyTestOwners =
	RegExp('## Host only framework tests\n(?<$kOwnerGroupName>.+)## Firebase tests', dotAll: true);
	final RegExp firebaselabTestOwners = RegExp('## Firebase tests\n(?<$kOwnerGroupName>.+)## Shards tests', dotAll: true);
	final RegExp shardTestOwners = RegExp('## Shards tests\n(?<$kOwnerGroupName>.+)', dotAll: true);

	// Utils methods

	/// Gets the existing flaky issues.
	///
	/// The state can be 'open', 'closed', or 'all'.
	Future<Map<String?, Issue>> getExistingIssues(GithubService gitHub, RepositorySlug slug, {String state = 'all'}) async {
	final Map<String?, Issue> nameToExistingIssue = <String?, Issue>{};
	for (final Issue issue in await gitHub.listIssues(slug, state: state, labels: <String>[kFlakeLabel])) {
	if (issue.htmlUrl.contains('pull') == true) {
	// For some reason, this github api may also return pull requests.
	continue;
	}
	final Map<String, dynamic>? metaTags = retrieveMetaTagsFromContent(issue.body);
	if (metaTags != null) {
	final String? name = metaTags['name'] as String?;
	if (!nameToExistingIssue.containsKey(name) \|\| _isOtherIssueMoreImportant(nameToExistingIssue[name]!, issue)) {
	nameToExistingIssue[name] = issue;
	}
	}
	}
	return nameToExistingIssue;
	}

	/// Gets the existing open pull requests that make tests flaky.
	Future<Map<String?, PullRequest>> getExistingPRs(GithubService gitHub, RepositorySlug slug) async {
	final Map<String?, PullRequest> nameToExistingPRs = <String?, PullRequest>{};
	for (final PullRequest pr in await gitHub.listPullRequests(slug, null)) {
	try {
	if (pr.body == null) {
	continue;
	}
	final Map<String, dynamic>? metaTags = retrieveMetaTagsFromContent(pr.body!);
	if (metaTags != null) {
	nameToExistingPRs[metaTags['name'] as String] = pr;
	}
	} catch (e) {
	throw 'Unable to parse body of ${pr.htmlUrl}\n$e';
	}
	}
	return nameToExistingPRs;
	}

	/// File a GitHub flaky issue based on builder details in recent prod/staging runs.
	Future<Issue> fileFlakyIssue({
	required BuilderDetail builderDetail,
	required GithubService gitHub,
	required RepositorySlug slug,
	double threshold = kDefaultFlakyRatioThreshold,
	bool bringup = false,
	}) async {
	final IssueBuilder issueBuilder = IssueBuilder(
	statistic: builderDetail.statistic,
	ownership: builderDetail.ownership,
	threshold: kDefaultFlakyRatioThreshold,
	bringup: bringup,
	);
	return gitHub.createIssue(
	slug,
	title: issueBuilder.issueTitle,
	body: issueBuilder.issueBody,
	labels: issueBuilder.issueLabels,
	assignee: issueBuilder.issueAssignee,
	);
	}

	/// Looks up the owner of a builder in TESTOWNERS file.
	TestOwnership getTestOwnership(pb.Target target, BuilderType type, String testOwnersContent) {
	final TestOwner testOwner = TestOwner(type);
	return testOwner.getTestOwnership(target, testOwnersContent);
	}

	/// Gets the [BuilderType] of the builder by looking up the information in the
	/// ci.yaml.
	BuilderType getTypeForBuilder(String? targetName, CiYaml ciYaml, {bool unfilteredTargets = false}) {
	final List<String>? tags = _getTags(targetName, ciYaml, unfilteredTargets: unfilteredTargets);
	if (tags == null \|\| tags.isEmpty) {
	return BuilderType.unknown;
	}

	bool hasFrameworkTag = false;
	bool hasHostOnlyTag = false;
	// If tags contain 'shard', it must be a shard test.
	// If tags contain 'devicelab', it must be a devicelab test.
	// If tags contain 'firebaselab`, it must be a firebase tests.
	// Otherwise, it is framework host only test if its tags contain both
	// 'framework' and 'hostonly'.
	for (String tag in tags) {
	if (tag == kCiYamlTargetTagsFirebaselab) {
	return BuilderType.firebaselab;
	} else if (tag == kCiYamlTargetTagsShard) {
	return BuilderType.shard;
	} else if (tag == kCiYamlTargetTagsDevicelab) {
	return BuilderType.devicelab;
	} else if (tag == kCiYamlTargetTagsFramework) {
	hasFrameworkTag = true;
	} else if (tag == kCiYamlTargetTagsHostonly) {
	hasHostOnlyTag = true;
	}
	}
	return hasFrameworkTag && hasHostOnlyTag ? BuilderType.frameworkHostOnly : BuilderType.unknown;
	}

	List<String>? _getTags(String? targetName, CiYaml ciYaml, {bool unfilteredTargets = false}) {
	final Set<Target> allUniqueTargets = {};
	if (!unfilteredTargets) {
	allUniqueTargets.addAll(ciYaml.presubmitTargets);
	allUniqueTargets.addAll(ciYaml.postsubmitTargets);
	} else {
	allUniqueTargets.addAll(ciYaml.targets);
	}

	final Target? target = allUniqueTargets.firstWhereOrNull((element) => element.value.name == targetName);
	return target?.tags;
	}

	bool _isOtherIssueMoreImportant(Issue original, Issue other) {
	// Open issues are always more important than closed issues. If both issue
	// are closed, the one that is most recently created is more important.
	if (original.isOpen && other.isOpen) {
	throw 'There should not be two open issues for the same test';
	} else if (original.isOpen && other.isClosed) {
	return false;
	} else if (original.isClosed && other.isOpen) {
	return true;
	} else {
	return other.createdAt!.isAfter(original.createdAt!);
	}
	}

	String _buildHiddenMetaTags({String? name}) {
	return '''<!-- meta-tags: To be used by the automation script only, DO NOT MODIFY.
	{
	"name": "$name"
	}
	-->
	''';
	}

	final RegExp _issueHiddenMetaTagsRegex =
	RegExp(r'<!-- meta-tags: To be used by the automation script only, DO NOT MODIFY\.(?<meta>.+)-->', dotAll: true);

	/// Checks whether the github content contains meta tags and returns the meta
	/// tags if it does.
	///
	/// The script generated contents for issue bodies or pull request bodies
	/// contain the meta tags. Using this method is a reliable way to check whether
	/// a issue or pull request is generated by this script.
	Map<String, dynamic>? retrieveMetaTagsFromContent(String content) {
	final RegExpMatch? match = _issueHiddenMetaTagsRegex.firstMatch(content);
	if (match == null) {
	return null;
	}
	return jsonDecode(match.namedGroup('meta')!) as Map<String, dynamic>?;
	}

	String _formatRate(double rate) => (rate * 100).toStringAsFixed(2);

	String _issueBuildLinks({String? builder, required List<String> builds, Bucket bucket = Bucket.prod}) {
	return builds.map((String build) => _issueBuildLink(builder: builder, build: build, bucket: bucket)).join('\n');
	}

	String _issueSummary(BuilderStatistic statistic, double threshold, bool bringup) {
	final String summary;
	if (bringup) {
	summary =
	'The post-submit test builder `${statistic.name}`, which has been marked `bringup: true`, had ${statistic.flakyNumber} flakes over past ${statistic.totalNumber} commits.';
	} else {
	summary =
	'The post-submit test builder `${statistic.name}` had a flaky ratio ${_formatRate(statistic.flakyRate)}% for the past (up to) 100 commits, which is above our ${_formatRate(threshold)}% threshold.';
	}
	return summary;
	}

	String _issueBuildLink({String? builder, String? build, Bucket bucket = Bucket.prod}) {
	final String buildPrefix = bucket == Bucket.staging ? _stagingBuildPrefix : _prodBuildPrefix;
	return Uri.encodeFull('$buildPrefix$builder/$build');
	}

	String _issueBuilderLink(String? builder) {
	return Uri.encodeFull('$_buildDashboardPrefix?taskFilter=$builder');
	}

	String? getTeamLabelFromTeam(Team? team) {
	return switch (team) {
	Team.framework => kFrameworkLabel,
	Team.engine => kEngineLabel,
	Team.tool => kToolLabel,
	Team.web => kWebLabel,
	Team.infra => kInfraLabel,
	Team.android => kAndroidLabel,
	Team.ios => kIosLabel,
	Team.release => kReleaseLabel,
	Team.plugins => kEcosystemLabel,
	Team.unknown \|\| null => null,
	};
	}

	enum BuilderType {
	devicelab,
	frameworkHostOnly,
	shard,
	firebaselab,
	unknown,
	}

	enum Bucket {
	prod,
	staging,
	}

	enum Team {
	framework,
	engine,
	tool,
	web,
	infra,
	android,
	ios,
	release,
	plugins,
	unknown,
	}

	class TestOwnership {
	TestOwnership(
	this.owner,
	this.team,
	);
	String? owner;
	Team? team;
	}

	class BuilderDetail {
	const BuilderDetail({
	required this.statistic,
	required this.existingIssue,
	required this.existingPullRequest,
	required this.isMarkedFlaky,
	required this.ownership,
	required this.type,
	});
	final BuilderStatistic statistic;
	final Issue? existingIssue;
	final PullRequest? existingPullRequest;
	final TestOwnership ownership;
	final bool isMarkedFlaky;
	final BuilderType type;
	}