bpo-26128: Added __init__to subprocess.STARTUPINFO (#171)

The Windows-specific subprocess.STARTUPINFO class now accepts
keyword-only arguments to its constructor to set the various
data attributes.

Patch by Subhendu Ghosh.

2 files changed, 23 insertions, 5 deletions

diff --git a/Lib/subprocess.py b/Lib/subprocess.py
index 67b9c9f..dffcda3 100644
--- a/Lib/subprocess.py
+++ b/Lib/subprocess.py
@@ -127,11 +127,13 @@ if _mswindows:
     import msvcrt
     import _winapi
     class STARTUPINFO:
-        dwFlags = 0
-        hStdInput = None
-        hStdOutput = None
-        hStdError = None
-        wShowWindow = 0
+        def __init__(self, *, dwFlags=0, hStdInput=None, hStdOutput=None,
+                     hStdError=None, wShowWindow=0):
+            self.dwFlags = dwFlags
+            self.hStdInput = hStdInput
+            self.hStdOutput = hStdOutput
+            self.hStdError = hStdError
+            self.wShowWindow = wShowWindow
 else:
     import _posixsubprocess
     import select
diff --git a/Lib/test/test_subprocess.py b/Lib/test/test_subprocess.py
index 82e0b87..812e7bf 100644
--- a/Lib/test/test_subprocess.py
+++ b/Lib/test/test_subprocess.py
@@ -2550,6 +2550,22 @@ class Win32ProcessTestCase(BaseTestCase):
         subprocess.call([sys.executable, "-c", "import sys; sys.exit(0)"],
                         startupinfo=startupinfo)
 
+    def test_startupinfo_keywords(self):
+        # startupinfo argument
+        # We use hardcoded constants, because we do not want to
+        # depend on win32all.
+        STARTF_USERSHOWWINDOW = 1
+        SW_MAXIMIZE = 3
+        startupinfo = subprocess.STARTUPINFO(
+            dwFlags=STARTF_USERSHOWWINDOW,
+            wShowWindow=SW_MAXIMIZE
+        )
+        # Since Python is a console process, it won't be affected
+        # by wShowWindow, but the argument should be silently
+        # ignored
+        subprocess.call([sys.executable, "-c", "import sys; sys.exit(0)"],
+                        startupinfo=startupinfo)
+
     def test_creationflags(self):
         # creationflags argument
         CREATE_NEW_CONSOLE = 16