From 199c7b4ab961efb6692af0a1e30981250dd44ad0 Mon Sep 17 00:00:00 2001
From: Sam Rawlins <srawlins@google.com>
Date: Fri, 30 Aug 2024 08:54:02 -0700
Subject: [PATCH] Display indirectly implemented types via extended and
 mixed-in types (#3855)

---
 lib/src/model/inheriting_container.dart | 58 ++++++++++++-------
 test/classes_test.dart                  | 77 ++++++++++++++++++++++---
 test/src/utils.dart                     | 33 +++++------
 test/templates/class_test.dart          | 51 ++++++++++++----
 4 files changed, 160 insertions(+), 59 deletions(-)

diff --git a/lib/src/model/inheriting_container.dart b/lib/src/model/inheriting_container.dart
index bd30943e16..4fc64ce8b5 100644
--- a/lib/src/model/inheriting_container.dart
+++ b/lib/src/model/inheriting_container.dart
@@ -453,38 +453,52 @@ abstract class InheritingContainer extends Container {
       }
     }
 
-    for (var interface in directInterfaces) {
-      var interfaceElement = interface.modelElement;
+    void addFromSupertype(DefinedElementType supertype,
+        {required bool addSupertypes}) {
+      var superElement = supertype.modelElement;
 
       /// Do not recurse if we can find an element here.
-      if (interfaceElement.canonicalModelElement != null) {
-        addInterfaceIfUnique(interface);
-        continue;
+      if (superElement.canonicalModelElement != null) {
+        if (addSupertypes) addInterfaceIfUnique(supertype);
+        return;
       }
-      // Public types used to be unconditionally exposed here.  However,
-      // if the packages are [DocumentLocation.missing] we generally treat types
-      // defined in them as actually defined in a documented package.
-      // That translates to them being defined here, but in 'src/' or similar,
-      // and so, are now always hidden.
-
-      // This type is not backed by a canonical Class; search
-      // the superchain and publicInterfaces of this interface to pretend
-      // as though the hidden class didn't exist and this class was declared
-      // directly referencing the canonical classes further up the chain.
-      if (interfaceElement is! InheritingContainer) {
+
+      // This type is not backed by a canonical Class; it is not documented.
+      // Search it's `superChain` and `publicInterfaces` to pretend that `this`
+      // container directly implements canonical classes further up the chain.
+
+      if (superElement is! InheritingContainer) {
         assert(
           false,
-          'Can not handle intermediate non-public interfaces created by '
+          'Cannot handle intermediate non-public interfaces created by '
           "ModelElements that are not classes or mixins: '$fullyQualifiedName' "
-          "contains an interface '$interface', defined by '$interfaceElement'",
+          "contains a supertype '$supertype', defined by '$superElement'",
         );
-        continue;
+        return;
       }
-      var publicSuperChain = interfaceElement.superChain.wherePublic;
-      if (publicSuperChain.isNotEmpty) {
+      var publicSuperChain = superElement.superChain.wherePublic;
+      if (publicSuperChain.isNotEmpty && addSupertypes) {
         addInterfaceIfUnique(publicSuperChain.first);
       }
-      interfaceElement.publicInterfaces.forEach(addInterfaceIfUnique);
+      superElement.publicInterfaces.forEach(addInterfaceIfUnique);
+    }
+
+    for (var interface in directInterfaces) {
+      addFromSupertype(interface, addSupertypes: true);
+    }
+    for (var supertype in superChain) {
+      var interfaceElement = supertype.modelElement;
+
+      // Do not recurse if we can find an element here.
+      if (interfaceElement.canonicalModelElement != null) {
+        continue;
+      }
+      addFromSupertype(supertype, addSupertypes: false);
+    }
+    if (this case Class(:var mixedInTypes) || Enum(:var mixedInTypes)) {
+      for (var mixin in mixedInTypes) {
+        addFromSupertype(mixin, addSupertypes: false);
+      }
     }
     return interfaces;
   }
diff --git a/test/classes_test.dart b/test/classes_test.dart
index 6b33d307c5..584e24b627 100644
--- a/test/classes_test.dart
+++ b/test/classes_test.dart
@@ -25,9 +25,9 @@ class C {}
 extension Ex on C {}
 ''');
 
-    var f = library.classes.named('C');
+    var c = library.classes.named('C');
     expect(
-      f.potentiallyApplicableExtensionsSorted,
+      c.potentiallyApplicableExtensionsSorted,
       contains(library.extensions.named('Ex')),
     );
   }
@@ -38,9 +38,9 @@ class C<T> {}
 extension Ex on C<int> {}
 ''');
 
-    var f = library.classes.named('C');
+    var c = library.classes.named('C');
     expect(
-      f.potentiallyApplicableExtensionsSorted,
+      c.potentiallyApplicableExtensionsSorted,
       contains(library.extensions.named('Ex')),
     );
   }
@@ -52,9 +52,9 @@ class D extends C {}
 extension Ex on C {}
 ''');
 
-    var f = library.classes.named('D');
+    var d = library.classes.named('D');
     expect(
-      f.potentiallyApplicableExtensionsSorted,
+      d.potentiallyApplicableExtensionsSorted,
       contains(library.extensions.named('Ex')),
     );
   }
@@ -66,9 +66,9 @@ class D<T> extends C<T> {}
 extension Ex on C<int> {}
 ''');
 
-    var f = library.classes.named('D');
+    var d = library.classes.named('D');
     expect(
-      f.potentiallyApplicableExtensionsSorted,
+      d.potentiallyApplicableExtensionsSorted,
       contains(library.extensions.named('Ex')),
     );
   }
@@ -109,6 +109,67 @@ class C implements _B {}
     expect(c.publicInterfaces.first.modelElement, library.classes.named('A'));
   }
 
+  void test_publicInterfaces_indirectViaPrivate2() async {
+    var library = await bootPackageWithLibrary('''
+class A {}
+class _B implements A {}
+class _C implements _B {}
+class D implements _C {}
+''');
+
+    var d = library.classes.named('D');
+    expect(d.publicInterfaces, hasLength(1));
+    expect(d.publicInterfaces.first.modelElement, library.classes.named('A'));
+  }
+
+  void test_publicInterfaces_indirectViaPrivateExtendedClass() async {
+    var library = await bootPackageWithLibrary('''
+class A {}
+class _B implements A {}
+class C extends _B {}
+''');
+
+    var c = library.classes.named('C');
+    expect(c.publicInterfaces, hasLength(1));
+    expect(c.publicInterfaces.first.modelElement, library.classes.named('A'));
+  }
+
+  void test_publicInterfaces_indirectViaPrivateExtendedClass2() async {
+    var library = await bootPackageWithLibrary('''
+class A {}
+class _B implements A {}
+class _C extends _B {}
+class D extends _C {}
+''');
+
+    var c = library.classes.named('D');
+    expect(c.publicInterfaces, hasLength(1));
+    expect(c.publicInterfaces.first.modelElement, library.classes.named('A'));
+  }
+
+  void test_publicInterfaces_onlyExtendedClasses() async {
+    var library = await bootPackageWithLibrary('''
+class A {}
+class B extends A {}
+class _C extends B {}
+class D extends _C {}
+''');
+
+    expect(library.classes.named('D').publicInterfaces, isEmpty);
+  }
+
+  void test_publicInterfaces_indirectViaPrivateMixedInMixin() async {
+    var library = await bootPackageWithLibrary('''
+class A {}
+mixin _M implements A {}
+class C with _M {}
+''');
+
+    var c = library.classes.named('C');
+    expect(c.publicInterfaces, hasLength(1));
+    expect(c.publicInterfaces.first.modelElement, library.classes.named('A'));
+  }
+
   void test_publicInterfaces_indirectViaPrivate_multiply() async {
     var library = await bootPackageWithLibrary('''
 class A<T> {}
diff --git a/test/src/utils.dart b/test/src/utils.dart
index 7028b0d553..97dea526a4 100644
--- a/test/src/utils.dart
+++ b/test/src/utils.dart
@@ -322,35 +322,34 @@ MatchingLinkResult referenceLookup(Warnable element, String codeRef) =>
 
 /// Returns a matcher which compresses consecutive whitespace in [text] into a
 /// single space.
-Matcher matchesCompressed(String text) => matches(RegExp(text.replaceAll(
-      RegExp(r'\s\s+', multiLine: true),
-      ' *',
-    )));
-
-/// We can not use [ExperimentalFeature.releaseVersion] or even
-/// [ExperimentalFeature.experimentalReleaseVersion] as these are set to `null`
-/// even when partial analyzer implementations are available.
+Matcher matchesCompressed(String text) => matches(RegExp(
+      text.replaceAll(RegExp(r'\s\s+', multiLine: true), r'\s*'),
+    ));
+
+// We can not use `ExperimentalFeature.releaseVersion` or even
+// `ExperimentalFeature.experimentalReleaseVersion` as these are set to `null`
+// even when partial analyzer implementations are available.
 bool get namedArgumentsAnywhereAllowed =>
     VersionRange(min: Version.parse('2.17.0-0'), includeMin: true)
         .allows(platformVersion);
 
-/// We can not use [ExperimentalFeature.releaseVersion] or even
-/// [ExperimentalFeature.experimentalReleaseVersion] as these are set to `null`
-/// even when partial analyzer implementations are available.
+// We can not use `ExperimentalFeature.releaseVersion` or even
+// `ExperimentalFeature.experimentalReleaseVersion` as these are set to `null`
+// even when partial analyzer implementations are available.
 bool get recordsAllowed =>
     VersionRange(min: Version.parse('2.19.0-0'), includeMin: true)
         .allows(platformVersion);
 
-/// We can not use [ExperimentalFeature.releaseVersion] or even
-/// [ExperimentalFeature.experimentalReleaseVersion] as these are set to `null`
-/// even when partial analyzer implementations are available.
+// We can not use `ExperimentalFeature.releaseVersion` or even
+// `ExperimentalFeature.experimentalReleaseVersion` as these are set to `null`
+// even when partial analyzer implementations are available.
 bool get extensionTypesAllowed =>
     VersionRange(min: Version.parse('3.2.0-0.0-dev'), includeMin: true)
         .allows(platformVersion);
 
-/// We can not use [ExperimentalFeature.releaseVersion] or even
-/// [ExperimentalFeature.experimentalReleaseVersion] as these are set to `null`
-/// even when partial analyzer implementations are available.
+// We can not use `ExperimentalFeature.releaseVersion` or even
+// `ExperimentalFeature.experimentalReleaseVersion` as these are set to `null`
+// even when partial analyzer implementations are available.
 bool get classModifiersAllowed =>
     VersionRange(min: Version.parse('3.0.0-0.0-dev'), includeMin: true)
         .allows(platformVersion);
diff --git a/test/templates/class_test.dart b/test/templates/class_test.dart
index f57dd6c772..10a76c2aac 100644
--- a/test/templates/class_test.dart
+++ b/test/templates/class_test.dart
@@ -46,12 +46,36 @@ class Foo implements _Foo {}
 ''');
     var baseLines = readLines(['lib', 'Base-class.html']);
 
-    baseLines.expectMainContentContainsAllInOrder([
-      matches('<dt>Implementers</dt>'),
-      matches('<dd><ul class="comma-separated clazz-relationships">'),
-      matches('<li><a href="../lib/Foo-class.html">Foo</a></li>'),
-      matches('</ul></dd>'),
-    ]);
+    expect(
+      baseLines.join('\n'),
+      matchesCompressed('''
+        <dt>Implementers</dt>
+        <dd><ul class="comma-separated clazz-relationships">
+            <li><a href="../lib/Foo-class.html">Foo</a></li>
+        </ul></dd>
+'''),
+    );
+  }
+
+  void test_implementers_class_extends2() async {
+    await createPackageWithLibrary('''
+abstract class A {}
+abstract class B extends A {}
+class _C extends B {}
+class D extends _C {}
+''');
+    var baseLines = readLines(['lib', 'A-class.html']);
+
+    expect(
+      baseLines.join('\n'),
+      // D should not be found; it is indirect via B.
+      matchesCompressed('''
+        <dt>Implementers</dt>
+        <dd><ul class="comma-separated clazz-relationships">
+            <li><a href="../lib/B-class.html">B</a></li>
+        </ul></dd>
+'''),
+    );
   }
 
   void test_implementers_class_implements_withGenericType() async {
@@ -61,12 +85,15 @@ class Foo<E> implements Base<E> {}
 ''');
     var baseLines = readLines(['lib', 'Base-class.html']);
 
-    baseLines.expectMainContentContainsAllInOrder([
-      matches('<dt>Implementers</dt>'),
-      matches('<dd><ul class="comma-separated clazz-relationships">'),
-      matches('<li><a href="../lib/Foo-class.html">Foo</a></li>'),
-      matches('</ul></dd>'),
-    ]);
+    expect(
+      baseLines.join('\n'),
+      matchesCompressed(r'''
+        <dt>Implementers</dt>
+        <dd><ul class="comma-separated clazz-relationships">
+          <li><a href="../lib/Foo-class.html">Foo</a></li>
+        </ul></dd>
+'''),
+    );
   }
 
   void test_implementers_class_implements_withInstantiatedType() async {