From d37bbaae2fe4fdd04e57d20fec38b6ab15493689 Mon Sep 17 00:00:00 2001
From: Iain Bullard <iain.bullard@gmail.com>
Date: Wed, 12 Jul 2017 08:47:24 +0000
Subject: [PATCH] fix: fix _precache memory leak from LazySuite

LazySuite keeps all a reference to all tests (even those that have been
run) under self._precache. When running a large number of tests this can
cause nose to use up all available system memory. This makes running the
whole test suite impossible.

This change fixes that issue and keeps the behaviour of LazySuite.__nonzero__
intact. All tests pass under python 2.7 that passed prior to the change
(there are some for the coverage plugin that didn't and still don't
pass).
---
 nose/suite.py | 26 ++++++++++++++------------
 1 file changed, 14 insertions(+), 12 deletions(-)

diff --git a/nose/suite.py b/nose/suite.py
index a3699a1a..48bffbbb 100644
--- a/nose/suite.py
+++ b/nose/suite.py
@@ -66,6 +66,7 @@ def __hash__(self):
 
     def addTest(self, test):
         self._precache.append(test)
+        self._had_precache = True
 
     # added to bypass run changes in 2.7's unittest
     def run(self, result):
@@ -79,21 +80,21 @@ def __nonzero__(self):
         log.debug("tests in %s?", id(self))
         if self._precache:
             return True
-        if self.test_generator is None:
-            return False
-        try:
-            test = self.test_generator.next()
-            if test is not None:
-                self._precache.append(test)
-                return True
-        except StopIteration:
-            pass
-        return False
+        if self.test_generator is not None:
+            try:
+                test = self.test_generator.next()
+                if test is not None:
+                    self.addTest(test)
+                    return True
+            except StopIteration:
+                pass
+
+        return self._had_precache
 
     def _get_tests(self):
         log.debug("precache is %s", self._precache)
-        for test in self._precache:
-            yield test
+        while self._precache:
+            yield self._precache.pop(0)
         if self.test_generator is None:
             return
         for test in self.test_generator:
@@ -101,6 +102,7 @@ def _get_tests(self):
 
     def _set_tests(self, tests):
         self._precache = []
+        self._had_precache = False
         is_suite = isinstance(tests, unittest.TestSuite)
         if callable(tests) and not is_suite:
             self.test_generator = tests()