Typeshed#stubFilesSymbols should not contain null symbols for ambigous third party symbols (#1049)

Author: andrea-guarino-sonarsource

python-frontend/src/main/java/org/sonar/python/types/TypeShed.java

@@ -165,7 +165,14 @@ public static Collection<Symbol> stubFilesSymbols() {
     Set<Symbol> symbols = new HashSet<>(TypeShed.builtinSymbols().values());
     for (Map<String, Symbol> symbolsByFqn : typeShedSymbols.values()) {
       for (Symbol symbol : symbolsByFqn.values()) {
-        symbols.add(isAmbiguousSymbolOfClasses(symbol) ? disambiguateWithLatestPythonSymbol(((AmbiguousSymbol) symbol).alternatives()) : symbol);
+        Symbol stubSymbol = symbol;
+        if (isAmbiguousSymbolOfClasses(symbol)) {
+          Symbol disambiguatedSymbol = disambiguateWithLatestPythonSymbol(((AmbiguousSymbol) symbol).alternatives());
+          if (disambiguatedSymbol != null) {
+            stubSymbol = disambiguatedSymbol;
+          }
+        }
+        symbols.add(stubSymbol);
       }
     }
     return symbols;
@@ -283,6 +290,7 @@ private static Map<String, Symbol> searchTypeShedForModule(String moduleName) {
    * This method sort ambiguous symbol by python version and returns the one which is valid for
    * the most recent Python version.
    */
+  @CheckForNull
   static Symbol disambiguateWithLatestPythonSymbol(Set<Symbol> alternatives) {
     int max = Integer.MIN_VALUE;
     Symbol latestPythonSymbol = null;

python-frontend/src/test/java/org/sonar/python/types/TypeShedTest.java

@@ -528,4 +528,12 @@ public void typeshed_private_modules_should_not_affect_fqn()  {
     assertThat(socket.declaredMembers()).extracting(Symbol::name, Symbol::fullyQualifiedName).contains(tuple("connect", "socket.socket.connect"));
     assertThat(socket.superClasses()).extracting(Symbol::fullyQualifiedName).containsExactly("object");
   }
+
+  @Test
+  public void stubFilesSymbols_third_party_symbols_should_not_be_null() {
+    // six modules contain ambiguous symbols that only contain class symbols
+    // however third party symbols don't have validForPythonVersions field set
+    symbolsForModule("six");
+    assertThat(TypeShed.stubFilesSymbols()).doesNotContainNull();
+  }
 }