When raising warning, always use stacklevel=2

B028: No explicit stacklevel argument found. The warn method from
the warnings module uses a stacklevel of 1 by default. This will
only show a stack trace for the line on which the warn method is
called. It is therefore recommended to use a stacklevel of 2 or
greater to provide more information to the user.

Signed-off-by: Giampaolo Rodola <g.rodola@gmail.com>

psutil/_common.py

@@ -372,7 +372,7 @@ def __init__(self, seconds, pid=None, name=None):
     if isinstance(__builtins__, dict):  # cpython
         exec_ = __builtins__["exec"]
     else:  # pypy
-        exec_ = getattr(__builtins__, "exec")
+        exec_ = getattr(__builtins__, "exec")  # noqa
 
     exec_("""def raise_from(value, from_value):
     try:

psutil/_pslinux.py

@@ -510,7 +510,7 @@ def virtual_memory():
         msg = "%s memory stats couldn't be determined and %s set to 0" % (
             ", ".join(missing_fields),
             "was" if len(missing_fields) == 1 else "were")
-        warnings.warn(msg, RuntimeWarning)
+        warnings.warn(msg, RuntimeWarning, stacklevel=2)
 
     return svmem(total, avail, percent, used, free,
                  active, inactive, buffers, cached, shared, slab)
@@ -544,7 +544,7 @@ def swap_memory():
         # see https://github.com/giampaolo/psutil/issues/722
         msg = "'sin' and 'sout' swap memory stats couldn't " \
               "be determined and were set to 0 (%s)" % str(err)
-        warnings.warn(msg, RuntimeWarning)
+        warnings.warn(msg, RuntimeWarning, stacklevel=2)
         sin = sout = 0
     else:
         with f:
@@ -564,7 +564,7 @@ def swap_memory():
                 # https://github.com/giampaolo/psutil/issues/313
                 msg = "'sin' and 'sout' swap memory stats couldn't " \
                       "be determined and were set to 0"
-                warnings.warn(msg, RuntimeWarning)
+                warnings.warn(msg, RuntimeWarning, stacklevel=2)
                 sin = sout = 0
     return _common.sswap(total, used, free, percent, sin, sout)
 

psutil/tests/__init__.py

@@ -248,7 +248,7 @@ def attempt(exe):
     # Let's use the base python in this case.
     base = getattr(sys, "_base_executable", None)
     if WINDOWS and sys.version_info >= (3, 7) and base is not None:
-        # We need to set __PYVENV_LAUNCHER__ to sys.executable for the 
+        # We need to set __PYVENV_LAUNCHER__ to sys.executable for the
         # base python executable to know about the environment.
         env["__PYVENV_LAUNCHER__"] = sys.executable
         return base, env
@@ -1737,7 +1737,7 @@ def import_module_by_path(path):
 
 def warn(msg):
     """Raise a warning msg."""
-    warnings.warn(msg, UserWarning)
+    warnings.warn(msg, UserWarning, stacklevel=2)
 
 
 def is_namedtuple(x):