From 645005e947c13c4a0706310a2a46112bf63cadc0 Mon Sep 17 00:00:00 2001
From: Andrey Doroschenko <dorosch.github.io@yandex.ru>
Date: Sun, 17 Nov 2019 17:08:31 +0300
Subject: bpo-38724: Implement subprocess.Popen.__repr__ (GH-17151)

---
 Lib/subprocess.py                                  |  9 ++++++++
 Lib/test/test_subprocess.py                        | 24 ++++++++++++++++++++++
 .../2019-11-14-14-13-29.bpo-38724.T5ySfR.rst       |  1 +
 3 files changed, 34 insertions(+)
 create mode 100644 Misc/NEWS.d/next/Library/2019-11-14-14-13-29.bpo-38724.T5ySfR.rst

diff --git a/Lib/subprocess.py b/Lib/subprocess.py
index b5a45d9..ba6f198 100644
--- a/Lib/subprocess.py
+++ b/Lib/subprocess.py
@@ -978,6 +978,15 @@ class Popen(object):
 
             raise
 
+    def __repr__(self):
+        obj_repr = (
+            f"<{self.__class__.__name__}: "
+            f"returncode: {self.returncode} args: {list(self.args)!r}>"
+        )
+        if len(obj_repr) > 80:
+            obj_repr = obj_repr[:76] + "...>"
+        return obj_repr
+
     @property
     def universal_newlines(self):
         # universal_newlines as retained as an alias of text_mode for API
diff --git a/Lib/test/test_subprocess.py b/Lib/test/test_subprocess.py
index 9e96a6d..97dc09c 100644
--- a/Lib/test/test_subprocess.py
+++ b/Lib/test/test_subprocess.py
@@ -1360,6 +1360,30 @@ class ProcessTestCase(BaseTestCase):
         self.addCleanup(p.stdin.close)
         p.communicate(b"x" * 2**20)
 
+    def test_repr(self):
+        # Run a command that waits for user input, to check the repr() of
+        # a Proc object while and after the sub-process runs.
+        code = 'import sys; input(); sys.exit(57)'
+        cmd = [sys.executable, '-c', code]
+        result = "<Popen: returncode: {}"
+
+        with subprocess.Popen(
+                cmd, stdin=subprocess.PIPE, universal_newlines=True) as proc:
+            self.assertIsNone(proc.returncode)
+            self.assertTrue(
+                repr(proc).startswith(result.format(proc.returncode)) and
+                repr(proc).endswith('>')
+            )
+
+            proc.communicate(input='exit...\n')
+            proc.wait()
+
+            self.assertIsNotNone(proc.returncode)
+            self.assertTrue(
+                repr(proc).startswith(result.format(proc.returncode)) and
+                repr(proc).endswith('>')
+            )
+
     def test_communicate_epipe_only_stdin(self):
         # Issue 10963: communicate() should hide EPIPE
         p = subprocess.Popen(ZERO_RETURN_CMD,
diff --git a/Misc/NEWS.d/next/Library/2019-11-14-14-13-29.bpo-38724.T5ySfR.rst b/Misc/NEWS.d/next/Library/2019-11-14-14-13-29.bpo-38724.T5ySfR.rst
new file mode 100644
index 0000000..a5ebfb3
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2019-11-14-14-13-29.bpo-38724.T5ySfR.rst
@@ -0,0 +1 @@
+Add a repr for ``subprocess.Popen`` objects. Patch by Andrey Doroschenko.
\ No newline at end of file
-- 
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