From 4dbe727d87e42f0923aabf065441c46aec18c182 Mon Sep 17 00:00:00 2001
From: Mikhail Golubev <mikhail.golubev@jetbrains.com>
Date: Thu, 18 Nov 2021 23:20:18 +0200
Subject: [PATCH] EA-404000 Fix NPE in case of unresolved class names in class
 patterns

GitOrigin-RevId: c1805f264367e026c22b12a714eb97b6acd8edec
---
 .../psi/impl/references/PyKeywordPatternReference.java   | 9 ++++-----
 ...ssPatternLeadsToNothingSuggestedForKeywordPatterns.py | 3 +++
 .../testSrc/com/jetbrains/python/Py3CompletionTest.java  | 5 +++++
 3 files changed, 12 insertions(+), 5 deletions(-)
 create mode 100644 python/testData/completion/unresolvedClassPatternLeadsToNothingSuggestedForKeywordPatterns.py

diff --git a/python/python-psi-impl/src/com/jetbrains/python/psi/impl/references/PyKeywordPatternReference.java b/python/python-psi-impl/src/com/jetbrains/python/psi/impl/references/PyKeywordPatternReference.java
index 48853cb96e79..10487cba9919 100644
--- a/python/python-psi-impl/src/com/jetbrains/python/psi/impl/references/PyKeywordPatternReference.java
+++ b/python/python-psi-impl/src/com/jetbrains/python/psi/impl/references/PyKeywordPatternReference.java
@@ -13,9 +13,8 @@ import com.jetbrains.python.PythonCodeStyleService;
 import com.jetbrains.python.codeInsight.completion.OverwriteEqualsInsertHandler;
 import com.jetbrains.python.psi.*;
 import com.jetbrains.python.psi.resolve.PyResolveContext;
+import com.jetbrains.python.psi.types.PyClassLikeType;
 import com.jetbrains.python.psi.types.PyInstantiableType;
-import com.jetbrains.python.psi.types.PyType;
-import com.jetbrains.python.psi.types.PyTypeUtil;
 import com.jetbrains.python.psi.types.TypeEvalContext;
 import one.util.streamex.StreamEx;
 import org.jetbrains.annotations.NotNull;
@@ -90,15 +89,15 @@ public final class PyKeywordPatternReference extends PsiReferenceBase.Poly<PyKey
     return true;
   }
 
-  @Nullable
-  private static PyType resolveToClassTypes(@NotNull PyClassPattern classPattern, @NotNull PyResolveContext resolveContext) {
+  @NotNull
+  private static List<PyClassLikeType> resolveToClassTypes(@NotNull PyClassPattern classPattern, @NotNull PyResolveContext resolveContext) {
     List<PsiElement> elements = PyUtil.multiResolveTopPriority(classPattern.getClassNameReference(), resolveContext);
     return StreamEx.of(elements)
       .select(PyClass.class)
       .map(e -> e.getType(resolveContext.getTypeEvalContext()))
       .nonNull()
       .map(PyInstantiableType::toInstance)
-      .collect(PyTypeUtil.toUnion());
+      .toList();
   }
 
   private static class KeywordAttributeLookupDecorator extends LookupElementDecorator<LookupElement> {
diff --git a/python/testData/completion/unresolvedClassPatternLeadsToNothingSuggestedForKeywordPatterns.py b/python/testData/completion/unresolvedClassPatternLeadsToNothingSuggestedForKeywordPatterns.py
new file mode 100644
index 000000000000..8461f336f6aa
--- /dev/null
+++ b/python/testData/completion/unresolvedClassPatternLeadsToNothingSuggestedForKeywordPatterns.py
@@ -0,0 +1,3 @@
+match x:
+    case MyClass(attr<caret>):
+        pass
diff --git a/python/testSrc/com/jetbrains/python/Py3CompletionTest.java b/python/testSrc/com/jetbrains/python/Py3CompletionTest.java
index dbdf9d6cee89..d088e2615d23 100644
--- a/python/testSrc/com/jetbrains/python/Py3CompletionTest.java
+++ b/python/testSrc/com/jetbrains/python/Py3CompletionTest.java
@@ -616,6 +616,11 @@ public class Py3CompletionTest extends PyTestCase {
     doNegativeTest();
   }
 
+  // EA-404000
+  public void testUnresolvedClassPatternLeadsToNothingSuggestedForKeywordPatterns() {
+    doNegativeTest();
+  }
+
   // PY-48012
   public void testAttributesOfDataclassSuggestedForKeywordPatterns() {
     final String testName = getTestName(true);