A better way to deal with StopEverything exceptions

2 files changed, 16 insertions, 6 deletions

diff --git a/coverage/cmdline.py b/coverage/cmdline.py
index 9d9d6536..ce929f48 100644
--- a/coverage/cmdline.py
+++ b/coverage/cmdline.py
@@ -13,7 +13,7 @@ import traceback
 from coverage import env
 from coverage.collector import CTracer
 from coverage.execfile import run_python_file, run_python_module
-from coverage.misc import CoverageException, ExceptionDuringRun, NoSource
+from coverage.misc import BaseCoverageException, ExceptionDuringRun, NoSource
 from coverage.debug import info_formatter, info_header
 
 
@@ -760,7 +760,7 @@ def main(argv=None):
         # exception.
         traceback.print_exception(*err.args)
         status = ERR
-    except CoverageException as err:
+    except BaseCoverageException as err:
         # A controlled error inside coverage.py: print the message to the user.
         print(err)
         status = ERR
diff --git a/coverage/misc.py b/coverage/misc.py
index cb9248d2..d3723e29 100644
--- a/coverage/misc.py
+++ b/coverage/misc.py
@@ -255,8 +255,13 @@ class SimpleRepr(object):
             )
 
 
-class CoverageException(Exception):
-    """An exception specific to coverage.py."""
+class BaseCoverageException(Exception):
+    """The base of all Coverage exceptions."""
+    pass
+
+
+class CoverageException(BaseCoverageException):
+    """A run-of-the-mill exception specific to coverage.py."""
     pass
 
 
@@ -298,6 +303,11 @@ class StopEverything(getattr(unittest, 'SkipTest', Exception)):
     pass
 
 
-class IncapablePython(CoverageException, StopEverything):
-    """An operation is attempted that this version of Python cannot do."""
+class IncapablePython(BaseCoverageException, StopEverything):
+    """An operation is attempted that this version of Python cannot do.
+
+    This is derived from BaseCoverageException, not CoverageException, so that
+    it won't get caught by 'except CoverageException'.
+
+    """
     pass