Minimal IronPython support.

IronPython is weird: 2.7.7 has "str is unicode", and unicode.encode produces
unicode!  f_lasti is missing, and frame globals are missing.

4 files changed, 14 insertions, 3 deletions

diff --git a/coverage/control.py b/coverage/control.py
index d42cbdcb..4cc76459 100644
--- a/coverage/control.py
+++ b/coverage/control.py
@@ -393,6 +393,10 @@ class Coverage(object):
         can't be determined, None is returned.
 
         """
+        if module_globals is None:          # pragma: only ironpython
+            # IronPython doesn't provide globals: https://github.com/IronLanguages/main/issues/1296
+            module_globals = {}
+
         dunder_name = module_globals.get('__name__', None)
 
         if isinstance(dunder_name, str) and dunder_name != '__main__':
@@ -441,7 +445,7 @@ class Coverage(object):
         # .pyc files can be moved after compilation (for example, by being
         # installed), we look for __file__ in the frame and prefer it to the
         # co_filename value.
-        dunder_file = frame.f_globals.get('__file__')
+        dunder_file = frame.f_globals and frame.f_globals.get('__file__')
         if dunder_file:
             filename = source_for_file(dunder_file)
             if original_filename and not original_filename.startswith('<'):
diff --git a/coverage/env.py b/coverage/env.py
index 528c774a..4699a1e5 100644
--- a/coverage/env.py
+++ b/coverage/env.py
@@ -17,6 +17,7 @@ if PYPY:
     PYPYVERSION = sys.pypy_version_info
 
 JYTHON = (platform.python_implementation() == 'Jython')
+IRONPYTHON = (platform.python_implementation() == 'IronPython')
 
 # Python versions.
 PYVERSION = sys.version_info
diff --git a/coverage/python.py b/coverage/python.py
index f75be60a..9418c386 100644
--- a/coverage/python.py
+++ b/coverage/python.py
@@ -26,7 +26,13 @@ def read_python_source(filename):
 
     """
     with open(filename, "rb") as f:
-        return f.read().replace(b"\r\n", b"\n").replace(b"\r", b"\n")
+        source = f.read()
+
+    if env.IRONPYTHON:
+        # IronPython reads Unicode strings even for "rb" files.
+        source = bytes(source)
+
+    return source.replace(b"\r\n", b"\n").replace(b"\r", b"\n")
 
 
 @contract(returns='unicode')
diff --git a/coverage/pytracer.py b/coverage/pytracer.py
index 3cf956fd..6dae0148 100644
--- a/coverage/pytracer.py
+++ b/coverage/pytracer.py
@@ -101,7 +101,7 @@ class PyTracer(object):
             # function calls and re-entering generators.  The f_lasti field is
             # -1 for calls, and a real offset for generators.  Use <0 as the
             # line number for calls, and the real line number for generators.
-            if frame.f_lasti < 0:
+            if getattr(frame, 'f_lasti', -1) < 0:
                 self.last_line = -frame.f_code.co_firstlineno
             else:
                 self.last_line = frame.f_lineno