bpo-33165: Added stacklevel parameter to logging APIs. (GH-7424)

Lib/logging/__init__.py

@@ -1397,7 +1397,7 @@ class Logger(Filterer):
         if self.isEnabledFor(level):
             self._log(level, msg, args, **kwargs)
 
-    def findCaller(self, stack_info=False):
+    def findCaller(self, stack_info=False, stacklevel=1):
         """
         Find the stack frame of the caller so that we can note the source
         file name, line number and function name.
@@ -1407,6 +1407,12 @@ class Logger(Filterer):
         #IronPython isn't run with -X:Frames.
         if f is not None:
             f = f.f_back
+        orig_f = f
+        while f and stacklevel > 1:
+            f = f.f_back
+            stacklevel -= 1
+        if not f:
+            f = orig_f
         rv = "(unknown file)", 0, "(unknown function)", None
         while hasattr(f, "f_code"):
             co = f.f_code
@@ -1442,7 +1448,8 @@ class Logger(Filterer):
                 rv.__dict__[key] = extra[key]
         return rv
 
-    def _log(self, level, msg, args, exc_info=None, extra=None, stack_info=False):
+    def _log(self, level, msg, args, exc_info=None, extra=None, stack_info=False,
+             stacklevel=1):
         """
         Low-level logging routine which creates a LogRecord and then calls
         all the handlers of this logger to handle the record.
@@ -1453,7 +1460,7 @@ class Logger(Filterer):
             #exception on some versions of IronPython. We trap it here so that
             #IronPython can use logging.
             try:
-                fn, lno, func, sinfo = self.findCaller(stack_info)
+                fn, lno, func, sinfo = self.findCaller(stack_info, stacklevel)
             except ValueError: # pragma: no cover
                 fn, lno, func = "(unknown file)", 0, "(unknown function)"
         else: # pragma: no cover

Lib/test/test_logging.py

@@ -4057,6 +4057,37 @@ class LoggerTest(BaseTest):
         self.assertEqual(len(called), 1)
         self.assertEqual('Stack (most recent call last):\n', called[0])
 
+    def test_find_caller_with_stacklevel(self):
+        the_level = 1
+
+        def innermost():
+            self.logger.warning('test', stacklevel=the_level)
+
+        def inner():
+            innermost()
+
+        def outer():
+            inner()
+
+        records = self.recording.records
+        outer()
+        self.assertEqual(records[-1].funcName, 'innermost')
+        lineno = records[-1].lineno
+        the_level += 1
+        outer()
+        self.assertEqual(records[-1].funcName, 'inner')
+        self.assertGreater(records[-1].lineno, lineno)
+        lineno = records[-1].lineno
+        the_level += 1
+        outer()
+        self.assertEqual(records[-1].funcName, 'outer')
+        self.assertGreater(records[-1].lineno, lineno)
+        lineno = records[-1].lineno
+        the_level += 1
+        outer()
+        self.assertEqual(records[-1].funcName, 'test_find_caller_with_stacklevel')
+        self.assertGreater(records[-1].lineno, lineno)
+
     def test_make_record_with_extra_overwrite(self):
         name = 'my record'
         level = 13