Reset all static variables to NULL in clar's __cleanup

Without this change, any failed assertion in the second (or a later) test
inside a test suite has a chance of double deleting memory, resulting in
a heap corruption. See #1096 for details.

This leaves alone the test cases where we "just" use cl_git_sandbox_init()
and cl_git_sandbox_cleanup(). These methods already take good care to not
double delete a repository.

Fixes #1096

3 files changed, 5 insertions, 1 deletions

diff --git a/tests-clar/repo/head.c b/tests-clar/repo/head.c
index 551e834f2..23d14d619 100644
--- a/tests-clar/repo/head.c
+++ b/tests-clar/repo/head.c
@@ -3,7 +3,7 @@
 #include "repo_helpers.h"
 #include "posix.h"
 
-git_repository *repo;
+static git_repository *repo;
 
 void test_repo_head__initialize(void)
 {
diff --git a/tests-clar/repo/init.c b/tests-clar/repo/init.c
index f76e8bc3d..f29f54091 100644
--- a/tests-clar/repo/init.c
+++ b/tests-clar/repo/init.c
@@ -19,6 +19,8 @@ void test_repo_init__initialize(void)
 static void cleanup_repository(void *path)
 {
 	git_repository_free(_repo);
+	_repo = NULL;
+
 	cl_fixture_cleanup((const char *)path);
 }
 
diff --git a/tests-clar/repo/setters.c b/tests-clar/repo/setters.c
index cd6e389ae..7e482dee1 100644
--- a/tests-clar/repo/setters.c
+++ b/tests-clar/repo/setters.c
@@ -17,6 +17,8 @@ void test_repo_setters__initialize(void)
 void test_repo_setters__cleanup(void)
 {
 	git_repository_free(repo);
+	repo = NULL;
+
 	cl_fixture_cleanup("testrepo.git");
 	cl_fixture_cleanup("new_workdir");
 }