Fix microsoft#24: 'Go to Definition' for relative imports not resolving directly to the appropriate module (microsoft#702)

* Fix microsoft#24: 'Go to Definition' for relative imports not resolving directly to the appropriate module

* Add test

Author: AlexanderSher

src/Analysis/Ast/Impl/Analyzer/PythonAnalyzer.cs

@@ -369,7 +369,15 @@ public Task<ImmutableArray<ModuleKey>> FindDependenciesAsync(PythonAnalyzerEntry
                             }
                             break;
                         case FromImportStatement fromImport:
-                            HandleSearchResults(isTypeshed, dependencies, moduleResolution, pathResolver.FindImports(module.FilePath, fromImport));
+                            var imports = pathResolver.FindImports(module.FilePath, fromImport);
+                            HandleSearchResults(isTypeshed, dependencies, moduleResolution, imports);
+                            if (imports is IImportChildrenSource childrenSource) {
+                                foreach (var name in fromImport.Names) {
+                                    if (childrenSource.TryGetChildImport(name.Name, out var childImport)) {
+                                        HandleSearchResults(isTypeshed, dependencies, moduleResolution, childImport);
+                                    }
+                                }
+                            }
                             break;
                     }
                 }

src/LanguageServer/Test/GoToDefinitionTests.cs

@@ -13,8 +13,11 @@
 // See the Apache Version 2.0 License for specific language governing
 // permissions and limitations under the License.
 
+using System;
+using System.IO;
 using System.Threading.Tasks;
 using FluentAssertions;
+using Microsoft.Python.Analysis.Documents;
 using Microsoft.Python.Core.Text;
 using Microsoft.Python.LanguageServer.Sources;
 using Microsoft.Python.LanguageServer.Tests.FluentAssertions;
@@ -161,5 +164,27 @@ class A(object):
             var reference = ds.FindDefinition(analysis, new SourceLocation(2, 12));
             reference.Should().BeNull();
         }
+
+        [TestMethod, Priority(0)]
+        public async Task GotoRelativeImportInExplicitPackage() {
+            var pkgPath = TestData.GetTestSpecificUri("pkg", "__init__.py");
+            var modPath = TestData.GetTestSpecificUri("pkg", "mod.py");
+            var subpkgPath = TestData.GetTestSpecificUri("pkg", "subpkg", "__init__.py");
+            var submodPath = TestData.GetTestSpecificUri("pkg", "submod", "__init__.py");
+
+            var root = TestData.GetTestSpecificRootUri().AbsolutePath;
+            await CreateServicesAsync(root, PythonVersions.LatestAvailable3X);
+            var rdt = Services.GetService<IRunningDocumentTable>();
+
+            rdt.OpenDocument(pkgPath, string.Empty);
+            rdt.OpenDocument(modPath, "hello = 'World'");
+            rdt.OpenDocument(subpkgPath, string.Empty);
+            var submod = rdt.OpenDocument(submodPath, "from .. import mod");
+
+            var analysis = await submod.GetAnalysisAsync(-1);
+            var ds = new DefinitionSource();
+            var reference = ds.FindDefinition(analysis, new SourceLocation(1, 18));
+            reference.uri.Should().Be(modPath);
+        }
     }
 }

src/UnitTests/Core/Impl/TestData.cs

@@ -80,9 +80,11 @@ public static Uri[] GetNextModuleUris(int count) {
         }
 
         public static Uri GetTestSpecificUri(string relativePath) => new Uri(GetTestSpecificPath(relativePath));
+        public static Uri GetTestSpecificUri(params string[] parts) => new Uri(GetTestSpecificPath(parts));
         public static Uri GetTestSpecificRootUri() => TestRunScopeAsyncLocal.Value.RootUri;
 
         public static string GetTestSpecificPath(string relativePath) => TestRunScopeAsyncLocal.Value.GetTestSpecificPath(relativePath);
+        public static string GetTestSpecificPath(params string[] parts) => TestRunScopeAsyncLocal.Value.GetTestSpecificPath(Path.Combine(parts));
         public static string GetTestRelativePath(Uri uri) => TestRunScopeAsyncLocal.Value.GetTestRelativePath(uri);
         public static string GetDefaultModulePath() => TestRunScopeAsyncLocal.Value.GetDefaultModulePath();
         public static string GetNextModulePath() => TestRunScopeAsyncLocal.Value.GetNextModulePath();