feat: add git diff in DartUtils

dangerfile.dart

@@ -4,7 +4,10 @@ import 'package:path/path.dart' show join, current;
 import 'package:danger_core/danger_core.dart';
 import 'package:danger_plugin_dart_test/danger_plugin_dart_test.dart';
 
-void main() {
+void main() async {
+  final fullDiff = await DangerUtils.getFullDiff();
+  message('There are ${fullDiff.length} changed files');
+
   if (danger.isGitHub) {
     if (danger.github.pr.title.contains('WIP') == true) {
       warn('PR is considered WIP');

packages/danger_core/lib/danger_core.dart

@@ -4,6 +4,7 @@
 library danger_core;
 
 export 'src/danger_executor.dart';
+export 'src/danger_utils.dart';
 export 'src/models/danger_dsl.dart';
 export 'src/models/bitbucket_cloud.dart';
 export 'src/models/git_dsl.dart';

packages/danger_core/lib/src/danger_utils.dart

@@ -1,10 +1,38 @@
 import 'dart:io';
 
+import 'package:danger_core/danger_core.dart';
+import 'package:danger_core/src/models/git_diff.dart';
+import 'package:danger_core/src/utils/git_diff_parser.dart';
+
 class DangerUtils {
-  Future<String> spawn(String command,
+  DangerUtils._();
+
+  static Future<String> spawn(String command,
       {List<String> arguments = const []}) async {
     final result = await Process.run(command, arguments);
 
     return result.stdout.toString().trim();
   }
+
+  static Future<List<GitDiff>> getFullDiff() async {
+    var base = '';
+
+    if (danger.isGitHub) {
+      base = danger.github.pr.base.ref;
+    } else if (danger.isBitbucketCloud) {
+      base = danger.bitbucketCloud.pr.destination.branch.name;
+    } else if (danger.isGitLab) {
+      base = danger.gitLab.mergeRequest.targetBranch;
+    } else {
+      base = danger.settings.cliArgs?['base'] ?? '';
+    }
+
+    if (base.isEmpty) {
+      throw 'Cannot find base branch';
+    }
+
+    final data =
+        await DangerUtils.spawn('git', arguments: ['diff', 'HEAD', base]);
+    return GitDiffParser.parse(data);
+  }
 }

packages/danger_core/lib/src/models/git_diff.dart

@@ -0,0 +1,28 @@
+class GitDiff {
+  final String fromFile;
+  final String toFile;
+  final List<DiffBlock> diffBlocks;
+
+  GitDiff(
+      {required this.fromFile, required this.toFile, required this.diffBlocks});
+}
+
+class DiffBlock {
+  final int fromStart;
+  final int fromEnd;
+  final int toStart;
+  final int toEnd;
+
+  final List<String> addedLines;
+  final List<String> removedLines;
+  final List<String> unchangedLines;
+
+  DiffBlock(
+      {required this.fromStart,
+      required this.fromEnd,
+      required this.toStart,
+      required this.toEnd,
+      required this.addedLines,
+      required this.removedLines,
+      required this.unchangedLines});
+}

packages/danger_core/lib/src/utils/git_diff_parser.dart

@@ -0,0 +1,58 @@
+import 'package:danger_core/src/models/git_diff.dart';
+
+class GitDiffParser {
+  GitDiffParser._();
+
+  static List<GitDiff> parse(String diffData) {
+    List<GitDiff> diffs = [];
+    List<String> lines = diffData.split('\n');
+    GitDiff? currentDiff;
+    DiffBlock? currentBlock;
+
+    for (var line in lines) {
+      if (line.startsWith('diff --git')) {
+        final fromFile = line.split(' ')[2].substring(2);
+        final toFile = line.split(' ')[3].substring(2);
+        currentDiff =
+            GitDiff(fromFile: fromFile, toFile: toFile, diffBlocks: []);
+        diffs.add(currentDiff);
+        continue;
+      }
+
+      if (line.startsWith('@@')) {
+        String header = line.substring(3);
+        List<String> parts = header.split(' ');
+        List<String> fromRange = parts[0].split(',');
+        List<String> toRange = parts[1].split(',');
+
+        final fromStart = int.parse(fromRange[0].substring(1));
+        final fromEnd = fromStart +
+            (fromRange.length > 1 ? int.parse(fromRange[1]) : 1) -
+            1;
+        final toStart = int.parse(toRange[0].substring(1));
+        final toEnd =
+            toStart + (toRange.length > 1 ? int.parse(toRange[1]) : 1) - 1;
+
+        currentBlock = DiffBlock(
+            fromStart: fromStart,
+            fromEnd: fromEnd,
+            toStart: toStart,
+            toEnd: toEnd,
+            addedLines: [],
+            removedLines: [],
+            unchangedLines: []);
+        currentDiff?.diffBlocks.add(currentBlock);
+      }
+
+      if (line.startsWith('+')) {
+        currentBlock?.addedLines.add(line.substring(1));
+      } else if (line.startsWith('-')) {
+        currentBlock?.removedLines.add(line.substring(1));
+      } else if (line.startsWith(' ')) {
+        currentBlock?.unchangedLines.add(line.substring(1));
+      }
+    }
+
+    return diffs;
+  }
+}

packages/danger_core/test/fixtures/diff/add_only.diff

@@ -0,0 +1,27 @@
+diff --git a/.github/workflows/verify_compatibility.yaml b/.github/workflows/verify_compatibility.yaml
+index 507cacb..701dd94 100644
+--- a/.github/workflows/verify_compatibility.yaml
++++ b/.github/workflows/verify_compatibility.yaml
+@@ -38,6 +38,22 @@ jobs:
+         run: dart pub get
+         working-directory: packages/danger_dart/
+
++      - name: Install app (non nullsafety) dependencies
++        run: dart pub get
++        working-directory: example/pre_nullsafety/
++
++      - name: Run danger local (non nullsafety)
++        run: danger_dart local
++        working-directory: example/pre_nullsafety/
++
++      - name: Install app dependencies (nullsafety)
++        run: dart pub get
++        working-directory: example/target_nullsafety/
++
++      - name: Run danger local (nullsafety)
++        run: danger_dart local
++        working-directory: example/target_nullsafety/
++
+       - name: Install plugin dependencies
+         run: dart pub get
+         working-directory: example/with_plugin/danger_plugin_example/

packages/danger_core/test/fixtures/diff/mix.diff

@@ -0,0 +1,27 @@
+diff --git a/example/dart3/pubspec.yaml b/example/pre_nullsafety/pubspec.yaml
+similarity index 64%
+rename from example/dart3/pubspec.yaml
+rename to example/pre_nullsafety/pubspec.yaml
+index 8aca558..9c93b1b 100644
+--- a/example/dart3/pubspec.yaml
++++ b/example/pre_nullsafety/pubspec.yaml
+@@ -1,13 +1,16 @@
+-name: danger_test_target_null_safety
++name: danger_test_pre_nullsafety
+ description: A simple command-line application.
+ # version: 1.0.0
+ # homepage: https://www.example.com
+
+ environment:
+-  sdk: ">=3.0.0 <4.0.0"
++  sdk: ">=2.7.0 <3.0.0"
++
++dependencies:
++  json_annotation: ^3.0.0
+
+ dev_dependencies:
+   lints: ^1.0.1
+-  path: ^1.8.3
++  path: ^1.8.0
+   danger_core:
+     path: ../../packages/danger_core

packages/danger_core/test/fixtures/diff/multiple_chunk.diff

@@ -0,0 +1,26 @@
+diff --git a/packages/danger_plugin_golden_reporter/pubspec.yaml b/packages/danger_plugin_golden_reporter/pubspec.yaml
+index eca2e35..a0d38bd 100644
+--- a/packages/danger_plugin_golden_reporter/pubspec.yaml
++++ b/packages/danger_plugin_golden_reporter/pubspec.yaml
+@@ -1,10 +1,10 @@
+ name: danger_plugin_golden_reporter
+ description: A Danger Dart plugin to display golden images on pull requests.
+-version: 2.0.0
++version: 1.0.0
+ homepage: https://github.com/danger/dart
+
+ environment:
+-  sdk: ">=3.0.0 <4.0.0"
++  sdk: ">=2.12.0 <3.0.0"
+
+ dependencies:
+   # danger_core: ">= 1.0.0 < 2.0.0"
+@@ -12,7 +12,7 @@ dependencies:
+     path: ../danger_core
+
+ dev_dependencies:
+-  lints: ^2.1.1
++  lints: ^1.0.1
+   test: ^1.20.2
+   mockito: ^5.1.0
+   build_runner: ^2.1.8