From 6cde287a1e7701907154189b28775898128ea5c7 Mon Sep 17 00:00:00 2001
From: Anthony Sottile <asottile@umich.edu>
Date: Tue, 23 Oct 2018 10:17:21 -0700
Subject: [PATCH] Install multi-hook repositories only once

---
 pre_commit/prefix.py     | 6 +++---
 pre_commit/repository.py | 6 +++---
 tests/repository_test.py | 6 +++---
 3 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/pre_commit/prefix.py b/pre_commit/prefix.py
index 073b3f54..f8a8a9d6 100644
--- a/pre_commit/prefix.py
+++ b/pre_commit/prefix.py
@@ -1,11 +1,11 @@
 from __future__ import unicode_literals
 
+import collections
 import os.path
 
 
-class Prefix(object):
-    def __init__(self, prefix_dir):
-        self.prefix_dir = prefix_dir
+class Prefix(collections.namedtuple('Prefix', ('prefix_dir',))):
+    __slots__ = ()
 
     def path(self, *parts):
         return os.path.normpath(os.path.join(self.prefix_dir, *parts))
diff --git a/pre_commit/repository.py b/pre_commit/repository.py
index d718c2ff..2a435506 100644
--- a/pre_commit/repository.py
+++ b/pre_commit/repository.py
@@ -179,12 +179,12 @@ class Repository(object):
         return Prefix(self.store.clone(repo, rev, deps))
 
     def _venvs(self):
-        ret = []
+        ret = set()
         for _, hook in self.hooks:
             language = hook['language']
             version = hook['language_version']
-            deps = hook['additional_dependencies']
-            ret.append((
+            deps = tuple(hook['additional_dependencies'])
+            ret.add((
                 self._prefix_from_deps(language, deps),
                 language, version, deps,
             ))
diff --git a/tests/repository_test.py b/tests/repository_test.py
index 4c76f9a0..8d578f39 100644
--- a/tests/repository_test.py
+++ b/tests/repository_test.py
@@ -466,7 +466,7 @@ def test_venvs(tempdir_factory, store):
     config = make_config_from_repo(path)
     repo = Repository.create(config, store)
     venv, = repo._venvs()
-    assert venv == (mock.ANY, 'python', python.get_default_version(), [])
+    assert venv == (mock.ANY, 'python', python.get_default_version(), ())
 
 
 def test_additional_dependencies(tempdir_factory, store):
@@ -474,8 +474,8 @@ def test_additional_dependencies(tempdir_factory, store):
     config = make_config_from_repo(path)
     config['hooks'][0]['additional_dependencies'] = ['pep8']
     repo = Repository.create(config, store)
-    venv, = repo._venvs()
-    assert venv == (mock.ANY, 'python', python.get_default_version(), ['pep8'])
+    env, = repo._venvs()
+    assert env == (mock.ANY, 'python', python.get_default_version(), ('pep8',))
 
 
 def test_additional_dependencies_roll_forward(tempdir_factory, store):