improved promt

Author: ievdokdm

app_dart/lib/src/request_handlers/analyze_logs.dart

@@ -106,32 +106,81 @@ final class AnalyzeLogs extends ApiRequestHandler {
     if (stdoutLogs.isEmpty) {
       throw NotFoundException('Logs Not Found for BuildId: $buildId');
     }
-    String? githubUrl;
-    for (final tag in build.tags) {
-      if (tag.key == 'github_link') {
-        githubUrl = tag.value;
-      }
+    String githubUrl;
+    final githubLinkTag = build.tags.firstWhereOrNull(
+      (tag) => tag.key == 'github_link',
+    );
+    if (githubLinkTag == null) {
+      log.warn('Could not find github_link tag in build $buildId');
+      githubUrl = 'http://github.com/$owner/$repo/pull/$prNumber';
+    } else {
+      githubUrl = githubLinkTag.value;
     }
 
     // 4. Feed text to genkit.
     final prompt =
-        '''
-You are a Senior Infrastructure Engineer specializing in the Flutter CI ecosystem.
+        '''You are a Senior Infrastructure Engineer specializing in the Flutter CI ecosystem.
+I will provide you with a link to github pull request and the logs of a failed build step in a LUCI build associated with that change.
+
+## Your task
 
-I will provide you with github pull request and the logs of a failed build step in a LUCI build associated with that change.
+### 1. Identify the specific test or command that failed.
 
-Your task is:
+### 2. Extract the error message or crash log.
 
-1. Identify the specific test or command that failed.
+### 3. Explain the most likely root cause in simple terms.
 
-2. Extract the error message or crash log.
+### 4. Suggest a potential fix if possible.
 
-3. Explain the most likely root cause in simple terms.
+## Workflow
 
-4. Suggest a potential fix if possible.
+### 1. Analyze Raw Log Output
 
-${githubUrl != null && githubUrl.isNotEmpty ? 'Link to GitHub Pull Request: $githubUrl' : ''}
+Analyze the raw log output for failure details. Do not skim the output; check the entire log. **The description of findings should include specific details for the failures (e.g., unformatted files, specific test names), not just the top-level command that failed.**
 
+### 2. Look for Failure Patterns
+
+#### Pattern A: Error Blocks (e.g., Linux Analyze)
+Search for blocks starting with `╡ERROR #`.
+Example:
+```
+╔═╡ERROR #1╞════════════════════════════════════════════════════════════════════
+║ Command: bin/cache/dart-sdk/bin/dart --enable-asserts /b/s/w/ir/x/w/flutter/dev/bots/analyze_snippet_code.dart --verbose
+║ Command exited with exit code 255 but expected zero exit code.
+║ Working directory: /b/s/w/ir/x/w/flutter
+╚═══════════════════════════════════════════════════════════════════════════════
+```
+
+#### Pattern B: Task Result JSON
+Search for "Task result:" followed by a JSON object.
+Example:
+```json
+Task result:
+{
+  "success": false,
+  "reason": "Task failed: PathNotFoundException: Cannot open file..."
+}
+```
+
+#### Pattern C: Failing Tests List
+For general Dart tests, look for a list at the end of the log starting with "Failing tests:".
+Example:
+```
+Failing tests:
+  test/general.shard/cache_test.dart: FontSubset artifacts for all platforms on arm64 hosts
+  test/general.shard/cache_test.dart: FontSubset artifacts on arm64 linux
+```
+
+#### Pattern D: Build Failures
+For build failures (e.g., engine tests failing at compile time), look for the following indicators in the logs or API summaries:
+- Lines starting with `FAILED:` (indicates a Ninja target failed).
+- Compiler error messages (e.g., `error:`, `fatal error:`).
+- Linker error messages (e.g., `undefined reference to`).
+- Summary messages in the check-runs API output like `1 build failed: [<build_name>]`.
+
+## Links
+
+Link to GitHub Pull Request: $githubUrl
 Links to Logs: ${stdoutLogs.join('\n')}
 ''';