Add submodules to completion list

src/Analysis/Ast/Impl/Modules/PythonModule.cs

@@ -24,6 +24,7 @@
 using Microsoft.Python.Analysis.Analyzer;
 using Microsoft.Python.Analysis.Analyzer.Evaluation;
 using Microsoft.Python.Analysis.Analyzer.Handlers;
+using Microsoft.Python.Analysis.Core.DependencyResolution;
 using Microsoft.Python.Analysis.Dependencies;
 using Microsoft.Python.Analysis.Diagnostics;
 using Microsoft.Python.Analysis.Documents;
@@ -148,9 +149,26 @@ public virtual string Documentation {
         #endregion
 
         #region IMemberContainer
-        public virtual IMember GetMember(string name) => GlobalScope.Variables[name]?.Value;
 
-        public virtual IEnumerable<string> GetMemberNames() => GlobalScope.GetExportableVariableNames();
+        public virtual IMember GetMember(string name) {
+            var v = GlobalScope.Variables[name]?.Value;
+            if (v == null) {
+                var mres = Interpreter.ModuleResolution;
+                var result = mres.CurrentPathResolver.FindImports(FilePath, Enumerable.Repeat(name, 1), 0, false);
+                if (result is ModuleImport moduleImports) {
+                    v = mres.GetImportedModule(moduleImports.FullName);
+                }
+            }
+            return v;
+        }
+
+        public virtual IEnumerable<string> GetMemberNames() {
+            var names = GlobalScope.GetExportableVariableNames();
+            // Get submodules since they may not be explicitly exported
+            // and yet are available. Consider 'pandas.io'.
+            var mi = Interpreter.ModuleResolution.CurrentPathResolver.GetModuleImportFromModuleName(Name);
+            return names.Concat(mi?.GetChildrenNames() ?? Enumerable.Empty<string>()).Distinct();
+        }
 
         #endregion
 

src/LanguageServer/Impl/Completion/ImportCompletion.cs

@@ -194,7 +194,7 @@ private static CompletionResult GetResultFromImportSearch(IImportSearchResult im
                             break;
                     }
 
-                    if (name != null && !memberNames.Contains(name)) {
+                    if (name != null && !completions.Any(c => c.label == name && c.kind == CompletionItemKind.Module)) {
                         completions.Add(CompletionItemSource.CreateCompletionItem(name, CompletionItemKind.Module));
                     }
                 }

src/LanguageServer/Test/CompletionTests.cs

@@ -1017,7 +1017,7 @@ public async Task FromDotInRootWithInitPy() {
 
             var cs = new CompletionSource(new PlainTextDocumentationSource(), ServerSettings.completion, Services);
             var result = cs.GetCompletions(analysis, new SourceLocation(1, 7));
-            result.Should().OnlyHaveLabels("__dict__", "__file__", "__doc__", "__package__", "__debug__", "__name__", "__path__", "__spec__");
+            result.Should().OnlyHaveLabels("__dict__", "__file__", "__doc__", "__package__", "__debug__", "__name__", "__path__", "__spec__", "module1");
         }
 
         [TestMethod, Priority(0)]
@@ -1511,5 +1511,39 @@ def print_EQ2(cls):
             result = cs.GetCompletions(analysis, new SourceLocation(12, 13));
             result.Should().HaveLabels("__EQ", "__NOT_EQ", "__OP_LIST");
         }
+
+        [DataTestMethod, Priority(0)]
+        [DataRow(true)]
+        [DataRow(false)]
+        public async Task ImplicitSubmodule(bool imported) {
+            var appUri = TestData.GetTestSpecificUri("app.py");
+            await TestData.CreateTestSpecificFileAsync(
+                Path.Combine("package", "__init__.py"),
+                imported ? "import package.m1 as m2" : string.Empty
+                );
+            await TestData.CreateTestSpecificFileAsync(Path.Combine("package", "m1", "__init__.py"), "x = 1");
+
+            await CreateServicesAsync(PythonVersions.LatestAvailable3X);
+            var rdt = Services.GetService<IRunningDocumentTable>();
+            const string code = @"
+import package
+package.
+package.m1.
+";
+            var doc = rdt.OpenDocument(appUri, code);
+
+            await Services.GetService<IPythonAnalyzer>().WaitForCompleteAnalysisAsync();
+            var analysis = await doc.GetAnalysisAsync(Timeout.Infinite);
+            var cs = new CompletionSource(new PlainTextDocumentationSource(), ServerSettings.completion, Services);
+
+            var result = cs.GetCompletions(analysis, new SourceLocation(3, 9));
+            result.Should().HaveLabels("m1");
+            result = cs.GetCompletions(analysis, new SourceLocation(4, 12));
+            if (imported) {
+                result.Should().HaveLabels("x");
+            } else {
+                result.Should().NotContainLabels("x");
+            }
+        }
     }
 }