resolveIfUnresolved function

Future<String?> resolveIfUnresolved(String projectPath)

Makes sure projectPath resolves, and returns what is wrong, or null.

Runs dart pub get --offline — about a second, no network, no writes when the resolution is current — and, only if that fails, dart pub get, which may download what the cache lost. A failure returns pub's own message, which names the real cause (version solving failed, a missing path dependency) instead of a downstream symptom. After a successful resolve, resolutionProblems must come back empty.

checkBridgeFreshness refuses an unresolved package, because resolving writes to it. A test of its own examples may resolve them as a setup step, as D4rtTester.prepareBridges does: what pub get writes — .dart_tool/ and pubspec.lock — is gitignored in this workspace.

Implementation

Future<String?> resolveIfUnresolved(String projectPath) async {
  final before = resolutionProblems(projectPath);

  var result = await _pubGet(projectPath, offline: true);
  if (result.exitCode != 0) {
    result = await _pubGet(projectPath, offline: false);
  }
  if (result.exitCode != 0) {
    return [
      '`dart pub get` failed in $projectPath:',
      '${result.stderr}'.trim(),
      if (before.isNotEmpty) ...[
        'Its package config was already broken:',
        ...before.map((problem) => '  $problem'),
      ],
    ].join('\n');
  }

  final after = resolutionProblems(projectPath);
  if (after.isEmpty) return null;
  return [
    '$projectPath resolved, but its package config is still broken:',
    ...after.map((problem) => '  $problem'),
  ].join('\n');
}