Migrate comment_referable and model_object_builder (#2832)

* squash

* fix error in filter setup

* fix test

Author: jcollins-g

lib/src/generator/generator.dart

@@ -7,7 +7,7 @@ library dartdoc.generator;
 
 import 'package:analyzer/file_system/file_system.dart';
 import 'package:dartdoc/src/dartdoc_options.dart';
-import 'package:dartdoc/src/model/model.dart' show PackageGraph;
+import 'package:dartdoc/src/model/package_graph.dart';
 import 'package:dartdoc/src/package_meta.dart';
 import 'package:dartdoc/src/warnings.dart';
 

lib/src/markdown_processor.dart

@@ -220,7 +220,8 @@ MatchingLinkResult _getMatchingLinkElementCommentReferable(
       allowTree = _rejectUnnamedAndShadowingConstructors;
     }
   }
-
+  allowTree ??= (_) => true;
+  filter ??= (_) => true;
   var lookupResult = warnable.referenceBy(commentReference.referenceBy,
       allowTree: allowTree, filter: filter);
 

lib/src/model/comment_referable.dart

@@ -2,8 +2,6 @@
 // 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.
 
-// @dart=2.9
-
 ///
 /// Code for managing comment reference lookups in dartdoc.
 ///
@@ -33,7 +31,7 @@ class ReferenceChildrenLookup {
 
 extension on Scope {
   /// Prefer the getter for a bundled lookup if both exist.
-  Element lookupPreferGetter(String id) {
+  Element? lookupPreferGetter(String id) {
     var result = lookup(id);
     return result.getter ?? result.setter;
   }
@@ -84,39 +82,40 @@ mixin CommentReferable implements Nameable, ModelBuilderInterface {
   /// For any [CommentReferable] where an analyzer [Scope] exists (or can
   /// be constructed), implement this.  This will take priority over
   /// lookups via [referenceChildren].  Can be cached.
-  Scope get scope => null;
+  Scope? get scope => null;
+
+  String? get href => null;
 
-  String get href => null;
+  static bool _alwaysTrue(CommentReferable? _) => true;
 
   /// Look up a comment reference by its component parts.  If [tryParents] is
   /// true, try looking up the same reference in any parents of [this].
   /// Will skip over results that do not pass a given [filter] and keep
   /// searching.  Will skip over entire subtrees whose parent node does
   /// not pass [allowTree].
   @nonVirtual
-  CommentReferable referenceBy(List<String> reference,
+  CommentReferable? referenceBy(List<String> reference,
       {bool tryParents = true,
-      bool Function(CommentReferable) filter,
-      bool Function(CommentReferable) allowTree,
-      Iterable<CommentReferable> parentOverrides}) {
-    filter ??= (r) => true;
-    allowTree ??= (r) => true;
+      bool Function(CommentReferable?) filter = _alwaysTrue,
+      bool Function(CommentReferable?) allowTree = _alwaysTrue,
+      Iterable<CommentReferable>? parentOverrides}) {
     parentOverrides ??= referenceParents;
     if (reference.isEmpty) {
       if (tryParents == false) return this;
       return null;
     }
-    CommentReferable result;
+    CommentReferable? result;
 
     /// Search for the reference.
     for (var referenceLookup in childLookups(reference)) {
       if (scope != null) {
-        result = lookupViaScope(referenceLookup, filter, allowTree);
+        result = lookupViaScope(referenceLookup,
+            filter: filter, allowTree: allowTree);
         if (result != null) break;
       }
       if (referenceChildren.containsKey(referenceLookup.lookup)) {
         result = recurseChildrenAndFilter(
-            referenceLookup, referenceChildren[referenceLookup.lookup],
+            referenceLookup, referenceChildren[referenceLookup.lookup]!,
             allowTree: allowTree, filter: filter);
         if (result != null) break;
       }
@@ -141,17 +140,16 @@ mixin CommentReferable implements Nameable, ModelBuilderInterface {
   /// Override if [Scope.lookup] may return elements not corresponding to a
   /// [CommentReferable], but you still want to have an implementation of
   /// [scope].
-  CommentReferable lookupViaScope(
-      ReferenceChildrenLookup referenceLookup,
-      bool Function(CommentReferable) allowTree,
-      bool Function(CommentReferable) filter) {
-    var resultElement = scope.lookupPreferGetter(referenceLookup.lookup);
+  CommentReferable? lookupViaScope(ReferenceChildrenLookup referenceLookup,
+      {required bool Function(CommentReferable?) allowTree,
+      required bool Function(CommentReferable?) filter}) {
+    var resultElement = scope!.lookupPreferGetter(referenceLookup.lookup);
     if (resultElement == null) return null;
     var result = modelBuilder.fromElement(resultElement);
     if (result is Accessor) {
-      result = (result as Accessor).enclosingCombo;
+      result = result.enclosingCombo;
     }
-    if (result?.enclosingElement is Container) {
+    if (result.enclosingElement is Container) {
       assert(false,
           '[Container] member detected, support not implemented for analyzer scope inside containers');
       return null;
@@ -164,26 +162,26 @@ mixin CommentReferable implements Nameable, ModelBuilderInterface {
   /// Given a [result] found in an implementation of [lookupViaScope] or
   /// [_lookupViaReferenceChildren], recurse through children, skipping over
   /// results that do not match the filter.
-  CommentReferable recurseChildrenAndFilter(
+  CommentReferable? recurseChildrenAndFilter(
       ReferenceChildrenLookup referenceLookup, CommentReferable result,
-      {bool Function(CommentReferable) allowTree,
-      bool Function(CommentReferable) filter}) {
-    assert(result != null);
+      {required bool Function(CommentReferable?) allowTree,
+      required bool Function(CommentReferable?) filter}) {
+    CommentReferable? returnValue = result;
     if (referenceLookup.remaining.isNotEmpty) {
       if (allowTree(result)) {
-        result = result.referenceBy(referenceLookup.remaining,
+        returnValue = result.referenceBy(referenceLookup.remaining,
             tryParents: false, allowTree: allowTree, filter: filter);
       } else {
-        result = null;
+        returnValue = null;
       }
     } else if (!filter(result)) {
-      result = result.referenceBy([referenceLookup.lookup],
+      returnValue = result.referenceBy([referenceLookup.lookup],
           tryParents: false, allowTree: allowTree, filter: filter);
     }
-    if (!filter(result)) {
-      result = null;
+    if (!filter(returnValue)) {
+      returnValue = null;
     }
-    return result;
+    return returnValue;
   }
 
   /// A list of lookups that should be attempted on children based on
@@ -218,15 +216,15 @@ mixin CommentReferable implements Nameable, ModelBuilderInterface {
   /// Replace the parents of parents.  [referenceBy] ignores whatever might
   /// otherwise be implied by the [referenceParents] of [referenceParents],
   /// replacing them with this.
-  Iterable<CommentReferable> get referenceGrandparentOverrides => null;
+  Iterable<CommentReferable>? get referenceGrandparentOverrides => null;
 
   // TODO(jcollins-g): Enforce that reference name is always the same
   // as [ModelElement.name].  Easier/possible after old lookup code is gone.
   String get referenceName => name;
 
   // TODO(jcollins-g): Eliminate need for this in markdown_processor.
-  Library get library => null;
+  Library? get library => null;
 
   // TODO(jcollins-g): Eliminate need for this in markdown_processor.
-  Element get element;
+  Element? get element;
 }

lib/src/model/model_object_builder.dart

@@ -2,8 +2,6 @@
 // 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.
 
-// @dart=2.9
-
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/dart/element/type.dart';
 import 'package:dartdoc/src/element_type.dart';
@@ -51,8 +49,7 @@ class ModelObjectBuilderImpl extends ModelObjectBuilder
 mixin ModelBuilder implements ModelBuilderInterface {
   PackageGraph get packageGraph;
 
-  ModelObjectBuilder _modelBuilder;
   @override
-  ModelObjectBuilder get modelBuilder =>
-      _modelBuilder ??= ModelObjectBuilderImpl(packageGraph);
+  late final ModelObjectBuilder modelBuilder =
+      ModelObjectBuilderImpl(packageGraph);
 }

test/comment_referable/comment_referable_test.dart

@@ -32,7 +32,7 @@ abstract class Base extends Nameable with CommentReferable {
           {bool Function(CommentReferable) allowTree,
           bool Function(CommentReferable) filter}) =>
       referenceBy(value.split(_separator),
-          allowTree: allowTree, filter: filter);
+          allowTree: allowTree ?? (_) => true, filter: filter ?? (_) => true);
 
   @override
   Element get element => throw UnimplementedError();