Repository: dart-lang/dartdoc (dart)

Issue:
type 'Null' is not a subtype of type 'List<String>' in type cast
I didn't check if this is fixed in the master branch, but it appears for a few packages on pub.dev
```console
$ export FLUTTER_ROOT=/workspace/flutter
$ ./reproduce-dartdoc-issue.sh input_country 2.1.0
Package dartdoc is currently active at version 6.2.0.
The package dartdoc is already activated at newest available version.
To recompile executables, first run `dart pub global deactivate dartdoc`.
Installed executable dartdoc.
Activated dartdoc 6.2.0.
Documenting input_country...                                                                                                                                                                                                           -
dartdoc 6.2.0 (/jonasfj/.pub-cache/global_packages/dartdoc/bin/dartdoc.dart-2.19.4.snapshot) failed: type 'Null' is not a subtype of type 'List<String>' in type cast
#0      _DartdocFileOption._valueAtFromFile (package:dartdoc/src/dartdoc_options.dart:967:47)
#1      _DartdocFileOption._valueAtFromFilesFirstFound (package:dartdoc/src/dartdoc_options.dart:892:15)
#2      _DartdocFileOption._valueAtFromFiles (package:dartdoc/src/dartdoc_options.dart:880:28)
#3      DartdocOptionArgFile.valueAt (package:dartdoc/src/dartdoc_options.dart:813:29)
#4      DartdocOptionContext.include (package:dartdoc/src/dartdoc_options.dart:1274:35)
#5      DartdocOptionContext.include (package:dartdoc/src/dartdoc_options.dart)
#6      PubPackageBuilder.getLibraries.<anonymous closure> (package:dartdoc/src/model/package_builder.dart:438:18)
#7      PubPackageBuilder._parseLibraries (package:dartdoc/src/model/package_builder.dart:252:30)
<asynchronous suspension>
#8      PubPackageBuilder.getLibraries (package:dartdoc/src/model/package_builder.dart:433:5)
<asynchronous suspension>
#9      PubPackageBuilder.buildPackageGraph (package:dartdoc/src/model/package_builder.dart:85:5)
<asynchronous suspension>
#10     Dartdoc.generateDocsBase (package:dartdoc/src/dartdoc.dart:202:24)
<asynchronous suspension>
#11     Dartdoc.generateDocs (package:dartdoc/src/dartdoc.dart:250:24)
<asynchronous suspension>
#12     Dartdoc.executeGuarded.<anonymous closure> (package:dartdoc/src/dartdoc.dart:288:9)
<asynchronous suspension>

```

Use the `reproduce-dartdoc-issue.sh` below to reproduce:

```bash
#!/bin/bash

set -e

DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"

P="$1"
V="$2"

if [ -z "$P" ]; then
  echo 'usage: ./reproduce-dartdoc-issue.sh <package> <version>'
  exit 1;
fi

if [ -z "$V" ]; then
  echo 'usage: ./reproduce-dartdoc-issue.sh <package> <version>'
  exit 1;
fi

cd $(mktemp -d)
curl -L "https://pub.dev/api/packages/$P/versions/$V/archive.tar.gz" | tar -xz
dart pub global activate dartdoc
dartdoc
```

Pull request description:
Fixes #3365.

New error message:

```
Documenting input_country...

dartdoc 6.2.0 (/Users/jcollins/dart/dartdoc/bin/dartdoc.dart) failed: Error in dartdoc_options.yaml, dartdoc.include: expecting a list of Strings, got `flutter_input`.
```

Patch:
diff --git a/lib/src/dartdoc_options.dart b/lib/src/dartdoc_options.dart
index 11e84387bd..d2ef289035 100644
--- a/lib/src/dartdoc_options.dart
+++ b/lib/src/dartdoc_options.dart
@@ -395,6 +395,17 @@ abstract class DartdocOption<T extends Object?> {
 
   bool get _isDouble => _kDoubleVal is T;
 
+  String get _expectedTypeForDisplay {
+    if (_isString) return 'String';
+    if (_isListString) return 'list of Strings';
+    if (_isMapString) return 'map of String to String';
+    if (_isBool) return 'boolean';
+    if (_isInt) return 'int';
+    if (_isDouble) return 'double';
+    assert(false, 'Expecting an unknown type');
+    return '<<unknown>>';
+  }
+
   final Map<String, _YamlFileData> __yamlAtCanonicalPathCache = {};
 
   /// Implementation detail for [DartdocOptionFileOnly].  Make sure we use
@@ -945,9 +956,8 @@ abstract class _DartdocFileOption<T> implements DartdocOption<T> {
         };
       }
       if (convertYamlToType == null) {
-        throw DartdocOptionError(
-            'Unable to convert yaml to type for option: $fieldName, method not '
-            'defined');
+        throw UnsupportedError(
+            '$fieldName: convertYamlToType method not defined');
       }
       var canonicalDirectoryPath =
           resourceProvider.pathContext.canonicalize(contextPath);
@@ -964,6 +974,10 @@ abstract class _DartdocFileOption<T> implements DartdocOption<T> {
     } else {
       throw UnsupportedError('Type $T is not supported');
     }
+    if (returnData == null) {
+      throw DartdocOptionError('Error in dartdoc_options.yaml, $fieldName: '
+          'expecting a $_expectedTypeForDisplay, got `$yamlData`');
+    }
     return _OptionValueWithContext(returnData as T, contextPath,
         definingFile: 'dartdoc_options.yaml');
   }


Test patch:
diff --git a/test/dartdoc_options_test.dart b/test/dartdoc_options_test.dart
index 803d14bfb7..05ba9c489f 100644
--- a/test/dartdoc_options_test.dart
+++ b/test/dartdoc_options_test.dart
@@ -40,6 +40,7 @@ class ConvertedOption {
 
 void main() {
   var resourceProvider = pubPackageMetaProvider.resourceProvider;
+  var path = pubPackageMetaProvider.resourceProvider.pathContext;
 
   late final DartdocOptionRoot dartdocOptionSetFiles;
   late final DartdocOptionRoot dartdocOptionSetArgs;
@@ -174,34 +175,30 @@ void main() {
     ));
 
     tempDir = resourceProvider.createSystemTemp('options_test');
-    firstDir = resourceProvider
-        .getFolder(resourceProvider.pathContext.join(tempDir.path, 'firstDir'))
+    firstDir = resourceProvider.getFolder(path.join(tempDir.path, 'firstDir'))
       ..create();
-    firstExisting = resourceProvider.getFile(
-        resourceProvider.pathContext.join(firstDir.path, 'existing.dart'))
+    firstExisting = resourceProvider
+        .getFile(path.join(firstDir.path, 'existing.dart'))
       ..writeAsStringSync('');
-    secondDir = resourceProvider
-        .getFolder(resourceProvider.pathContext.join(tempDir.path, 'secondDir'))
+    secondDir = resourceProvider.getFolder(path.join(tempDir.path, 'secondDir'))
       ..create();
     resourceProvider
-        .getFile(
-            resourceProvider.pathContext.join(secondDir.path, 'existing.dart'))
+        .getFile(path.join(secondDir.path, 'existing.dart'))
         .writeAsStringSync('');
 
-    secondDirFirstSub = resourceProvider.getFolder(
-        resourceProvider.pathContext.join(secondDir.path, 'firstSub'))
+    secondDirFirstSub = resourceProvider
+        .getFolder(path.join(secondDir.path, 'firstSub'))
       ..create();
-    secondDirSecondSub = resourceProvider.getFolder(
-        resourceProvider.pathContext.join(secondDir.path, 'secondSub'))
+    secondDirSecondSub = resourceProvider
+        .getFolder(path.join(secondDir.path, 'secondSub'))
       ..create();
 
-    dartdocOptionsOne = resourceProvider.getFile(resourceProvider.pathContext
-        .join(firstDir.path, 'dartdoc_options.yaml'));
-    dartdocOptionsTwo = resourceProvider.getFile(resourceProvider.pathContext
-        .join(secondDir.path, 'dartdoc_options.yaml'));
-    var dartdocOptionsTwoFirstSub = resourceProvider.getFile(resourceProvider
-        .pathContext
-        .join(secondDirFirstSub.path, 'dartdoc_options.yaml'));
+    dartdocOptionsOne = resourceProvider
+        .getFile(path.join(firstDir.path, 'dartdoc_options.yaml'));
+    dartdocOptionsTwo = resourceProvider
+        .getFile(path.join(secondDir.path, 'dartdoc_options.yaml'));
+    var dartdocOptionsTwoFirstSub = resourceProvider
+        .getFile(path.join(secondDirFirstSub.path, 'dartdoc_options.yaml'));
 
     dartdocOptionsOne.writeAsStringSync('''
 dartdoc:
@@ -247,6 +244,42 @@ dartdoc:
     }
   });
 
+  group('invalid data in yaml', () {
+    late Folder invalid;
+    late File dartdocOptionsInvalid;
+
+    setUp(() {
+      invalid = resourceProvider.getFolder(path.join(tempDir.path, 'invalid'))
+        ..create();
+      dartdocOptionsInvalid = resourceProvider
+          .getFile(path.join(invalid.path, 'dartdoc_options.yaml'));
+      dartdocOptionsInvalid.writeAsStringSync('''
+dartdoc:
+  categoryOrder: 'options_one'
+      ''');
+    });
+
+    tearDown(() {
+      try {
+        invalid.delete();
+      } catch (e) {
+        print('Ignoring error trying to delete temp: $e');
+      }
+    });
+
+    test('validate correct throw for wrong data type', () {
+      dartdocOptionSetFiles.parseArguments([]);
+      expect(() {
+        dartdocOptionSetFiles['categoryOrder'].valueAt(invalid);
+      },
+          throwsA(const TypeMatcher<DartdocOptionError>().having(
+              (e) => e.message,
+              'message',
+              equals('Error in dartdoc_options.yaml, dartdoc.categoryOrder: '
+                  'expecting a list of Strings, got `options_one`'))));
+    });
+  });
+
   group('new style synthetic option', () {
     test('validate argument override changes value', () {
       dartdocOptionSetSynthetic.parseArguments(['--my-special-integer', '12']);
@@ -272,10 +305,8 @@ dartdoc:
       } on DartdocFileMissing catch (e) {
         errorMessage = e.message;
       }
-      var missingPath = resourceProvider.pathContext.canonicalize(
-          resourceProvider.pathContext.join(
-              resourceProvider.pathContext.absolute(tempDir.path),
-              'existing.dart'));
+      var missingPath = path.canonicalize(
+          path.join(path.absolute(tempDir.path), 'existing.dart'));
       expect(
           errorMessage,
           equals('Synthetic configuration option vegetableLoaderChecked from '
@@ -296,7 +327,7 @@ dartdoc:
       // Since this is an ArgSynth, it ignores the yaml option and resolves to the CWD
       expect(
           dartdocOptionSetSynthetic['nonCriticalFileOption'].valueAt(firstDir),
-          equals(resourceProvider.pathContext.canonicalize('stuff.zip')));
+          equals(path.canonicalize('stuff.zip')));
     });
 
     test('ArgSynth defaults to synthetic', () {
@@ -320,10 +351,8 @@ dartdoc:
       } on DartdocFileMissing catch (e) {
         errorMessage = e.message;
       }
-      var missingPath = resourceProvider.pathContext.join(
-          resourceProvider.pathContext
-              .canonicalize(resourceProvider.pathContext.current),
-          'override-not-existing.dart');
+      var missingPath = path.join(
+          path.canonicalize(path.current), 'override-not-existing.dart');
       expect(
           errorMessage,
           equals('Argument --file-option, set to override-not-existing.dart, '
@@ -386,8 +415,7 @@ dartdoc:
     });
 
     group('glob options', () {
-      String canonicalize(String path) =>
-          resourceProvider.pathContext.canonicalize(path);
+      String canonicalize(String inputPath) => path.canonicalize(inputPath);
 
       test('work via the command line', () {
         dartdocOptionSetAll
@@ -395,11 +423,7 @@ dartdoc:
         expect(
             dartdocOptionSetAll['globOption'].valueAtCurrent(),
             equals([
-              resourceProvider.pathContext.joinAll([
-                canonicalize(resourceProvider.pathContext.current),
-                'foo',
-                '**'
-              ])
+              path.joinAll([canonicalize(path.current), 'foo', '**'])
             ]));
       });
 
@@ -408,25 +432,21 @@ dartdoc:
         expect(
             dartdocOptionSetAll['globOption'].valueAt(secondDir),
             equals([
-              canonicalize(
-                  resourceProvider.pathContext.join(secondDir.path, 'q*.html')),
-              canonicalize(
-                  resourceProvider.pathContext.join(secondDir.path, 'e*.dart')),
+              canonicalize(path.join(secondDir.path, 'q*.html')),
+              canonicalize(path.join(secondDir.path, 'e*.dart')),
             ]));
         // No child override, should be the same as parent
         expect(
             dartdocOptionSetAll['globOption'].valueAt(secondDirSecondSub),
             equals([
-              canonicalize(
-                  resourceProvider.pathContext.join(secondDir.path, 'q*.html')),
-              canonicalize(
-                  resourceProvider.pathContext.join(secondDir.path, 'e*.dart')),
+              canonicalize(path.join(secondDir.path, 'q*.html')),
+              canonicalize(path.join(secondDir.path, 'e*.dart')),
             ]));
         // Child directory overrides
         expect(
             dartdocOptionSetAll['globOption'].valueAt(secondDirFirstSub),
             equals([
-              resourceProvider.pathContext.joinAll(
+              path.joinAll(
                   [canonicalize(secondDirFirstSub.path), '**', '*.dart'])
             ]));
       });
@@ -464,10 +484,8 @@ dartdoc:
       } on DartdocFileMissing catch (e) {
         errorMessage = e.message;
       }
-      var missingPath = resourceProvider.pathContext.join(
-          resourceProvider.pathContext
-              .canonicalize(resourceProvider.pathContext.current),
-          'not_found.txt');
+      var missingPath =
+          path.join(path.canonicalize(path.current), 'not_found.txt');
       expect(
           errorMessage,
           equals('Argument --single-file, set to not_found.txt, resolves to '
@@ -478,7 +496,7 @@ dartdoc:
       String? errorMessage;
       dartdocOptionSetArgs.parseArguments([
         '--files-flag',
-        resourceProvider.pathContext.absolute(firstExisting.path),
+        path.absolute(firstExisting.path),
         '--files-flag',
         'other_not_found.txt'
       ]);
@@ -487,14 +505,12 @@ dartdoc:
       } on DartdocFileMissing catch (e) {
         errorMessage = e.message;
       }
-      var missingPath = resourceProvider.pathContext.join(
-          resourceProvider.pathContext
-              .canonicalize(resourceProvider.pathContext.current),
-          'other_not_found.txt');
+      var missingPath =
+          path.join(path.canonicalize(path.current), 'other_not_found.txt');
       expect(
           errorMessage,
           equals('Argument --files-flag, set to '
-              '[${resourceProvider.pathContext.absolute(firstExisting.path)}, '
+              '[${path.absolute(firstExisting.path)}, '
               'other_not_found.txt], resolves to missing path: '
               '"$missingPath"'));
     });
@@ -506,10 +522,8 @@ dartdoc:
           .parseArguments(['--unimportant-file', 'this-will-never-exist']);
       expect(
           dartdocOptionSetArgs['unimportantFile'].valueAt(tempDir),
-          equals(resourceProvider.pathContext.join(
-              resourceProvider.pathContext
-                  .canonicalize(resourceProvider.pathContext.current),
-              'this-will-never-exist')));
+          equals(path.join(
+              path.canonicalize(path.current), 'this-will-never-exist')));
     });
 
     test('DartdocOptionArgOnly has correct flag names', () {