Fix microsoft#370: Terminal Keyboard Inputs not being accepted

Make the debuggee process group the foreground group in its session.

Add a test for input(), and improve existing stdin test to cover more cases.

src/debugpy/launcher/debuggee.py

@@ -61,9 +61,26 @@ def spawn(process_name, cmdline, env, redirect_output):
             kwargs = {}
 
         if sys.platform != "win32":
-            # Start the debuggee in a new process group, so that the launcher can kill
-            # the entire process tree later.
-            kwargs.update(preexec_fn=os.setpgrp)
+
+            def preexec_fn():
+                # Start the debuggee in a new process group, so that the launcher can
+                # kill the entire process tree later.
+                os.setpgrp()
+
+                # Make the new process group the foreground group in its session, so
+                # that it can interact with the terminal. The debuggee will receive
+                # SIGTTOU when tcsetpgrp() is called, and must ignore it.
+                hdlr = signal.signal(signal.SIGTTOU, signal.SIG_IGN)
+                try:
+                    tty = os.open("/dev/tty", os.O_RDWR)
+                    try:
+                        os.tcsetpgrp(tty, os.getpgrp())
+                    finally:
+                        os.close(tty)
+                finally:
+                    signal.signal(signal.SIGTTOU, hdlr)
+
+            kwargs.update(preexec_fn=preexec_fn)
 
         try:
             global process
@@ -94,7 +111,9 @@ def spawn(process_name, cmdline, env, redirect_output):
 
                 # Setting this flag ensures that the job will be terminated by the OS once the
                 # launcher exits, even if it doesn't terminate the job explicitly.
-                job_info.BasicLimitInformation.LimitFlags |= winapi.JOB_OBJECT_LIMIT_KILL_ON_JOB_CLOSE
+                job_info.BasicLimitInformation.LimitFlags |= (
+                    winapi.JOB_OBJECT_LIMIT_KILL_ON_JOB_CLOSE
+                )
                 winapi.kernel32.SetInformationJobObject(
                     job_handle,
                     winapi.JobObjectExtendedLimitInformation,
@@ -103,7 +122,9 @@ def spawn(process_name, cmdline, env, redirect_output):
                 )
 
                 process_handle = winapi.kernel32.OpenProcess(
-                    winapi.PROCESS_TERMINATE | winapi.PROCESS_SET_QUOTA, False, process.pid
+                    winapi.PROCESS_TERMINATE | winapi.PROCESS_SET_QUOTA,
+                    False,
+                    process.pid,
                 )
 
                 winapi.kernel32.AssignProcessToJobObject(job_handle, process_handle)

tests/debugpy/test_input.py

@@ -0,0 +1,61 @@
+# Copyright (c) Microsoft Corporation. All rights reserved.
+# Licensed under the MIT License. See LICENSE in the project root
+# for license information.
+
+from __future__ import absolute_import, division, print_function, unicode_literals
+
+import pytest
+
+from tests import debug
+from tests.debug import runners
+
+
+@pytest.mark.parametrize("run", runners.all)
+@pytest.mark.parametrize("redirect_output", ["", "redirect_output"])
+def test_stdin_not_patched(pyfile, target, run, redirect_output):
+    @pyfile
+    def code_to_debug():
+        import sys
+        import debuggee
+        from debuggee import backchannel
+
+        debuggee.setup()
+        backchannel.send(sys.stdin is sys.__stdin__)
+
+    with debug.Session() as session:
+        session.config["redirectOutput"] = bool(redirect_output)
+
+        backchannel = session.open_backchannel()
+        with run(session, target(code_to_debug)):
+            pass
+
+        is_original_stdin = backchannel.receive()
+        assert is_original_stdin, "Expected sys.stdin and sys.__stdin__ to be the same."
+
+
+@pytest.mark.parametrize("run", runners.all_launch_terminal + runners.all_attach)
+@pytest.mark.parametrize("redirect_output", ["", "redirect_output"])
+def test_input(pyfile, target, run, redirect_output):
+    @pyfile
+    def code_to_debug():
+        import debuggee
+        from debuggee import backchannel
+
+        try:
+            input = raw_input
+        except NameError:
+            pass
+
+        debuggee.setup()
+        backchannel.send(input())
+
+    with debug.Session() as session:
+        session.config["redirectOutput"] = bool(redirect_output)
+
+        backchannel = session.open_backchannel()
+        with run(session, target(code_to_debug)):
+            pass
+
+        session.debuggee.stdin.write(b"ok\n")
+        s = backchannel.receive()
+        assert s == "ok"

tests/debugpy/test_output.py

@@ -122,24 +122,6 @@ def code_to_debug():
     )
 
 
-def test_stdin_not_patched(pyfile, target, run):
-    @pyfile
-    def code_to_debug():
-        import sys
-        import debuggee
-        from debuggee import backchannel
-
-        debuggee.setup()
-        backchannel.send(sys.stdin == sys.__stdin__)
-
-    with debug.Session() as session:
-        backchannel = session.open_backchannel()
-        with run(session, target(code_to_debug)):
-            pass
-        is_original_stdin = backchannel.receive()
-        assert is_original_stdin, 'Expected sys.stdin and sys.__stdin__ to be the same.'
-
-
 if sys.platform == "win32":
 
     @pytest.mark.parametrize("redirect_output", ["", "redirect_output"])