Merge pull request #12 from int19h/2052

Fix #2052: An error display in output window when debug with "Windows Application" option checked.

src/debugpy/launcher/output.py

@@ -29,11 +29,16 @@ class CaptureOutput(object):
         self.category = category
         self._whose = whose
         self._fd = fd
-        self._stream = stream if sys.version_info < (3,) else stream.buffer
         self._decoder = codecs.getincrementaldecoder("utf-8")(errors="surrogateescape")
-        self._encode = codecs.getencoder(
-            "utf-8" if stream.encoding is None else stream.encoding
-        )
+
+        if stream is None:
+            # Can happen if running under pythonw.exe.
+            self._stream = None
+        else:
+            self._stream = stream if sys.version_info < (3,) else stream.buffer
+            self._encode = codecs.getencoder(
+                "utf-8" if stream.encoding is None else stream.encoding
+            )
 
         self._worker_thread = threading.Thread(target=self._worker, name=category)
         self._worker_thread.start()
@@ -71,6 +76,9 @@ class CaptureOutput(object):
         except Exception:
             pass  # channel to adapter is already closed
 
+        if self._stream is None:
+            return
+
         s, _ = self._encode(s, "surrogateescape")
         size = len(s)
         i = 0

tests/debugpy/test_output.py

@@ -5,6 +5,7 @@
 from __future__ import absolute_import, division, print_function, unicode_literals
 
 import pytest
+import sys
 
 from tests import debug
 from tests.debug import runners
@@ -119,3 +120,32 @@ def test_non_ascii_output(pyfile, target, run):
         b"\xc3\xa9 \xc3\xa0 \xc3\xb6 \xc3\xb9\n",
         b"\xc3\x83\xc2\xa9 \xc3\x83\xc2\xa0 \xc3\x83\xc2\xb6 \xc3\x83\xc2\xb9\n",
     )
+
+
+if sys.platform == "win32":
+
+    @pytest.mark.parametrize("redirect_output", ["", "redirect_output"])
+    def test_pythonw_output(pyfile, target, run, redirect_output):
+        @pyfile
+        def code_to_debug():
+            import debuggee
+
+            debuggee.setup()
+            print("ok")
+            ()  # @wait_for_output
+
+        with debug.Session() as session:
+            # Don't capture launcher output - we want to see how it handles not
+            # having sys.stdin and sys.stdout available.
+            session.captured_output = set()
+
+            session.config["pythonPath"] = sys.executable + "/../pythonw.exe"
+            session.config["redirectOutput"] = bool(redirect_output)
+
+            with run(session, target(code_to_debug)):
+                session.set_breakpoints(code_to_debug, all)
+
+            session.wait_for_stop()
+            session.request_continue()
+
+        assert session.output("stdout") == ("ok\n" if redirect_output else "")