From ed160cbeebe45b5dc85c545e5d9f05ac078e395b Mon Sep 17 00:00:00 2001
From: Semyon Proshev <Semyon.Proshev@jetbrains.com>
Date: Wed, 10 Jun 2020 23:27:22 +0300
Subject: [PATCH] Provide type for `pathlib._PurePathBase` until PY-34617 is
 fixed (PY-30747)

GitOrigin-RevId: 25a707348036715ebb67280ea650a298cf882f4e
---
 .../stdlib/PyStdlibTypeProvider.java          | 30 +++++++++++++++++++
 .../Py3TypeCheckerInspectionTest.java         | 16 ++++++++++
 2 files changed, 46 insertions(+)

diff --git a/python/python-psi-impl/src/com/jetbrains/python/codeInsight/stdlib/PyStdlibTypeProvider.java b/python/python-psi-impl/src/com/jetbrains/python/codeInsight/stdlib/PyStdlibTypeProvider.java
index 61dbc8a4c6f4..7190d65876c8 100644
--- a/python/python-psi-impl/src/com/jetbrains/python/codeInsight/stdlib/PyStdlibTypeProvider.java
+++ b/python/python-psi-impl/src/com/jetbrains/python/codeInsight/stdlib/PyStdlibTypeProvider.java
@@ -16,6 +16,7 @@ import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
 import java.util.Arrays;
+import java.util.Collections;
 import java.util.List;
 import java.util.Set;
 
@@ -50,6 +51,10 @@ public class PyStdlibTypeProvider extends PyTypeProviderBase {
     if (type != null) {
       return Ref.create(type);
     }
+    type = getPathlibPurePathBaseType(referenceTarget);
+    if (type != null) {
+      return Ref.create(type);
+    }
     return null;
   }
 
@@ -129,6 +134,31 @@ public class PyStdlibTypeProvider extends PyTypeProviderBase {
     return null;
   }
 
+  @Nullable
+  private static PyType getPathlibPurePathBaseType(@NotNull PsiElement referenceTarget) {
+    if (referenceTarget instanceof PyTargetExpression &&
+        "pathlib._PurePathBase".equals(((PyTargetExpression)referenceTarget).getQualifiedName())) {
+      final PyBuiltinCache builtinCache = PyBuiltinCache.getInstance(referenceTarget);
+
+      if (LanguageLevel.forElement(referenceTarget).isOlderThan(LanguageLevel.PYTHON36)) {
+        final PyClassType objectType = builtinCache.getObjectType();
+        if (objectType != null) {
+          return objectType.toClass();
+        }
+      }
+
+      final PyClassType pathLikeType = builtinCache.getObjectType(PyNames.BUILTIN_PATH_LIKE);
+      final PyClassType strType = builtinCache.getStrType();
+      if (pathLikeType != null) {
+        return strType == null
+               ? pathLikeType.toClass()
+               : new PyCollectionTypeImpl(pathLikeType.getPyClass(), true, Collections.singletonList(strType));
+      }
+    }
+
+    return null;
+  }
+
   @Nullable
   @Override
   public Ref<PyType> getCallType(@NotNull PyFunction function, @NotNull PyCallSiteExpression callSite, @NotNull TypeEvalContext context) {
diff --git a/python/testSrc/com/jetbrains/python/inspections/Py3TypeCheckerInspectionTest.java b/python/testSrc/com/jetbrains/python/inspections/Py3TypeCheckerInspectionTest.java
index 37aeef4071de..4a20b27630ef 100644
--- a/python/testSrc/com/jetbrains/python/inspections/Py3TypeCheckerInspectionTest.java
+++ b/python/testSrc/com/jetbrains/python/inspections/Py3TypeCheckerInspectionTest.java
@@ -418,4 +418,20 @@ public class Py3TypeCheckerInspectionTest extends PyInspectionTestCase {
   public void testParametrizedBuiltinTypeAndTypingTypeAreEquivalent() {
     doTest();
   }
+
+  // PY-30747
+  public void testPathlibPathMatchingOsPathLike() {
+    doTestByText(
+      "import pathlib\n" +
+      "import os\n" +
+      "\n" +
+      "def foo(p: pathlib.Path):\n" +
+      "    with open(p) as file:\n" +
+      "        pass\n" +
+      "\n" +
+      "p1: pathlib.Path\n" +
+      "p2: os.PathLike[bytes] = p1  # false negative, see PyTypeChecker.matchGenerics\n" +
+      "p3: os.PathLike[str] = p1"
+    );
+  }
 }