python.pkgs.hglib: use patch to specify hg path (#57926)

pkgs/development/python-modules/hglib/default.nix

@@ -1,4 +1,4 @@
-{ stdenv, buildPythonPackage, fetchPypi, nose, mercurial, isPy3k }:
+{ stdenv, buildPythonPackage, fetchPypi, substituteAll, python, nose, mercurial }:
 
 buildPythonPackage rec {
   pname = "python-hglib";
@@ -9,11 +9,18 @@ buildPythonPackage rec {
     sha256 = "7c1fa0cb4d332dd6ec8409b04787ceba4623e97fb378656f7cab0b996c6ca3b2";
   };
 
-  checkInputs = [ nose ];
+  patches = [
-  buildInputs = [ mercurial ];
+    (substituteAll {
+      src = ./hgpath.patch;
+      hg = "${mercurial}/bin/hg";
+    })
+  ];
 
-  checkPhase = ''python test.py'';
+  checkInputs = [ nose ];
-  doCheck = if isPy3k then false else true;
+
+  checkPhase = ''
+    ${python.interpreter} test.py --with-hg "${mercurial}/bin/hg"
+  '';
 
   meta = with stdenv.lib; {
     description = "Mercurial Python library";

pkgs/development/python-modules/hglib/hgpath.patch

@@ -0,0 +1,24 @@
+diff -r 2d0ec6097d78 hglib/__init__.py
+--- a/hglib/__init__.py	Mon Apr 30 15:43:29 2018 +0900
++++ b/hglib/__init__.py	Tue Mar 19 23:30:01 2019 +0100
+@@ -1,7 +1,7 @@
+ import subprocess
+ from hglib import client, util, error
+ 
+-HGPATH = 'hg'
++HGPATH = '@hg@'
+ 
+ def open(path=None, encoding=None, configs=None):
+     '''starts a cmdserver for the given path (or for a repository found
+diff -r 2d0ec6097d78 tests/common.py
+--- a/tests/common.py	Mon Apr 30 15:43:29 2018 +0900
++++ b/tests/common.py	Tue Mar 19 23:30:01 2019 +0100
+@@ -26,7 +26,7 @@
+         os.mkdir(self._testtmp)
+         os.chdir(self._testtmp)
+         # until we can run norepo commands in the cmdserver
+-        os.system('hg init')
++        os.system('@hg@ init')
+         self.client = hglib.open()
+ 
+     def tearDown(self):