SONARPY-685 Fix false-positive with unformatted logger messages (#780)

Author: gyula-sallai-sonarsource

python-checks/src/main/java/org/sonar/python/checks/StringFormatCorrectnessCheck.java

@@ -128,20 +128,24 @@ private static void checkLoggerLog(SubscriptionContext ctx, CallExpression callE
       return;
     }
 
+    if (arguments.size() == 1) {
+      // If the logger is called without additional arguments, the message will not be parsed as a string format.
+      // However, we still want to report if we see a valid string format without any format arguments.
+      StringFormat.createFromPrintfStyle(IGNORE_SYNTAX_ERRORS, literal.trimmedQuotesValue()).ifPresent(format -> {
+        if (format.numExpectedArguments() != 0) {
+          reportIssue(ctx, firstArgument, literal, "Add argument(s) corresponding to the message's replacement field(s).");
+        }
+      });
+      return;
+    }
+
     Optional<StringFormat> formatOptional = StringFormat.createFromPrintfStyle(
       syntaxIssueReporter(ctx, firstArgument, literal), literal.trimmedQuotesValue());
     if (!formatOptional.isPresent()) {
       return;
     }
 
     StringFormat format = formatOptional.get();
-    if (arguments.size() == 1) {
-      if (format.numExpectedArguments() != 0) {
-        reportIssue(ctx, firstArgument, literal, "Add argument(s) corresponding to the message's replacement field(s).");
-      }
-      return;
-    }
-
     Token argIssueFrom = arguments.get(1).firstToken();
     Token argIssueTo = arguments.get(arguments.size() - 1).lastToken();
 

python-checks/src/test/resources/checks/stringFormatCorrectness.py

@@ -79,6 +79,8 @@ def logger_format():
     logging.error("%d", *t) # FN
     logging.error(msg="%d", kw1='42')
 
+    logging.error("This is valid % % %") # Ok
+
 import logging as renamed_logging
 renamed_logging.error("Foo %s", "Bar", 'Too many')  # Noncompliant