From 507ebeeb589210e9ae64212f990bb2e9fba4fb45 Mon Sep 17 00:00:00 2001
From: Anthony Scopatz <scopatz@gmail.com>
Date: Wed, 6 Jun 2018 12:04:52 -0400
Subject: [PATCH] threadable false

---
 news/hgi.rst            | 14 ++++++++++++++
 xonsh/commands_cache.py | 18 ++++++++++++++++++
 2 files changed, 32 insertions(+)
 create mode 100644 news/hgi.rst

diff --git a/news/hgi.rst b/news/hgi.rst
new file mode 100644
index 000000000..17005a90e
--- /dev/null
+++ b/news/hgi.rst
@@ -0,0 +1,14 @@
+**Added:** None
+
+**Changed:**
+
+* Mercurial (``hg``) will no longer run in a threadable subprocess when
+  it is run in interactive mode.
+
+**Deprecated:** None
+
+**Removed:** None
+
+**Fixed:** None
+
+**Security:** None
diff --git a/xonsh/commands_cache.py b/xonsh/commands_cache.py
index 1f3505939..b2f77f9e9 100644
--- a/xonsh/commands_cache.py
+++ b/xonsh/commands_cache.py
@@ -332,6 +332,23 @@ def predict_help_ver(args):
     return pred
 
 
+@lazyobject
+def HG_PREDICTOR_PARSER():
+    p = argparse.ArgumentParser('hg', add_help=False)
+    p.add_argument('command')
+    p.add_argument('-i', '--interactive', action='store_true', default=False,
+                   dest='interactive')
+    return p
+
+
+def predict_hg(args):
+    """Predict if mercurial is about to be run in interactive mode.
+    If it is interactive, predict False. If it isn't, predict True.
+    """
+    ns, _ = HG_PREDICTOR_PARSER.parse_known_args(args)
+    return not ns.interactive
+
+
 def default_threadable_predictors():
     """Generates a new defaultdict for known threadable predictors.
     The default is to predict true.
@@ -348,6 +365,7 @@ def default_threadable_predictors():
         'emacsclient': predict_false,
         'fish': predict_shell,
         'gvim': predict_help_ver,
+        'hg': predict_hg,
         'htop': predict_help_ver,
         'ipython': predict_shell,
         'ksh': predict_shell,