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.

7 files changed, 24 insertions, 3 deletions

diff --git a/CHANGES.rst b/CHANGES.rst
index 02924aae..6fca636a 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -16,6 +16,10 @@ Unreleased
   also continue measurement. Both `issue 79`_ and `issue 448`_ described this
   problem, and have been fixed.
 
+- Minimal IronPython support. You should be able to run IronPython programs
+  under ``coverage run``, though you will still have to do the reporting phase
+  with CPython.
+
 - Coverage.py has long had a special hack to support CPython's need to measure
   the coverage of the standard library tests. This code was not installed by
   kitted versions of coverage.py.  Now it is.
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
diff --git a/doc/index.rst b/doc/index.rst
index 29f79d75..98bd6a70 100644
--- a/doc/index.rst
+++ b/doc/index.rst
@@ -82,6 +82,8 @@ not.
 
     * Jython 2.7.1, though only for running code, not reporting.
 
+    * IronPython 2.7.7, though only for running code, not reporting.
+
     **This is a pre-release build.  The usual warnings about possible bugs
     apply.** The latest stable version is coverage.py 4.2, `described here`_.
 
diff --git a/metacov.ini b/metacov.ini
index b25af6eb..55d0225e 100644
--- a/metacov.ini
+++ b/metacov.ini
@@ -39,11 +39,15 @@ exclude_lines =
     pragma: only jython
     skip.*Jython
 
+    # IronPython isn't included in metacoverage.
+    pragma: only ironpython
+
 partial_branches =
     pragma: part covered
     pragma: if failure
     if env.TESTING:
     if .* env.JYTHON
+    if .* env.IRONPYTHON
 
 ignore_errors = true
 precision = 1