lib/src/rules/conditional_uri_does_not_exist.dart

// Copyright (c) 2021, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

import 'package:analyzer/dart/ast/ast.dart';
import 'package:analyzer/dart/ast/visitor.dart';
import 'package:analyzer/dart/element/element.dart';

import '../analyzer.dart';

const _desc = r'Missing conditional import.';

const _details = r'''
**DON'T** reference files that do not exist in conditional imports.

Code may fail at runtime if the condition evaluates such that the missing file
needs to be imported.

**BAD:**
```dart
import 'file_that_does_exist.dart'
  if (condition) 'file_that_does_not_exist.dart';
```

**GOOD:**
```dart
import 'file_that_does_exist.dart'
  if (condition) 'file_that_also_does_exist.dart';
```

''';

class ConditionalUriDoesNotExist extends LintRule {
  ConditionalUriDoesNotExist()
      : super(
            name: 'conditional_uri_does_not_exist',
            description: _desc,
            details: _details,
            group: Group.style);

  @override
  void registerNodeProcessors(
      NodeLintRegistry registry, LinterContext context) {
    var visitor = _Visitor(this);
    registry.addConfiguration(this, visitor);
  }
}

class _Visitor extends SimpleAstVisitor<void> {
  static const LintCode code = LintCode('conditional_uri_does_not_exist',
      "The target of the conditional URI '{0}' doesn't exist.",
      correctionMessage: 'Try creating the file referenced by the URI, or '
          'try using a URI for a file that does exist.');

  final LintRule rule;

  _Visitor(this.rule);

  @override
  void visitConfiguration(Configuration configuration) {
    var uri = configuration.resolvedUri;
    if (uri is DirectiveUriWithRelativeUriString) {
      var source = uri is DirectiveUriWithSource ? uri.source : null;
      // Checking source with .exists() will not detect the presence of overlays
      // in the analysis server (although running the script when the files
      // don't exist on disk would also fail to find it).
      if (!(source?.exists() ?? false)) {
        rule.reportLint(configuration.uri,
            arguments: [uri.relativeUriString], errorCode: code);
      }
    }
  }
}