SONARPY-932 Fix parse error: decorators can be any valid expression (#998)

Author: guillaume-dequenne

python-frontend/src/main/java/org/sonar/python/api/PythonGrammar.java

@@ -538,7 +538,7 @@ public static void compoundStatements(LexerfulGrammarBuilder b) {
     b.rule(FUN_RETURN_ANNOTATION).is("-", ">", TEST);
 
     b.rule(DECORATORS).is(b.oneOrMore(DECORATOR));
-    b.rule(DECORATOR).is("@", EXPR, NEWLINE);
+    b.rule(DECORATOR).is("@", NAMED_EXPR_TEST, NEWLINE);
     b.rule(DOTTED_NAME).is(NAME, b.zeroOrMore(".", NAME));
 
     b.rule(CLASSDEF).is(b.optional(DECORATORS), "class", CLASSNAME, b.optional("(", b.optional(ARGLIST), ")"), ":", SUITE);

python-frontend/src/main/java/org/sonar/python/tree/PythonTreeMaker.java

@@ -587,7 +587,7 @@ public FunctionDef funcDefStatement(AstNode astNode) {
 
   private Decorator decorator(AstNode astNode) {
     Token atToken = toPyToken(astNode.getFirstChild(PythonPunctuator.AT).getToken());
-    Expression expression = expression(astNode.getFirstChild(PythonGrammar.EXPR));
+    Expression expression = expression(astNode.getFirstChild(PythonGrammar.NAMED_EXPR_TEST));
     Token newLineToken = astNode.getFirstChild(PythonTokenType.NEWLINE) == null ? null : toPyToken(astNode.getFirstChild(PythonTokenType.NEWLINE).getToken());
     return new DecoratorImpl(atToken, expression, newLineToken);
   }

python-frontend/src/test/java/org/sonar/python/tree/PythonTreeMakerTest.java

@@ -902,6 +902,21 @@ public void decorators() {
     assertThat(decorator.name().names()).isEmpty();
     assertThat(TreeUtils.decoratorNameFromExpression(decorator.expression())).isNull();
     assertThat(decorator.expression().is(Kind.QUALIFIED_EXPR)).isTrue();
+
+    functionDef = funcDef("@hello() or bye()\ndef func(x): pass");
+    decorators = functionDef.decorators();
+    assertThat(decorators).hasSize(1);
+    decorator = decorators.get(0);
+    assertThat(decorator.expression().getKind()).isEqualTo(Kind.OR);
+    BinaryExpression binaryExpression = (BinaryExpression) decorator.expression();
+    assertThat(binaryExpression.leftOperand().getKind()).isEqualTo(Kind.CALL_EXPR);
+    assertThat(binaryExpression.rightOperand().getKind()).isEqualTo(Kind.CALL_EXPR);
+
+    functionDef = funcDef("@b:=some_decorator\ndef func(x): pass");
+    decorators = functionDef.decorators();
+    assertThat(decorators).hasSize(1);
+    decorator = decorators.get(0);
+    assertThat(decorator.expression().getKind()).isEqualTo(Kind.ASSIGNMENT_EXPRESSION);
   }
 
   private FunctionDef funcDef(String code) {