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

7 files changed, 19 insertions, 0 deletions

diff --git a/tests-clar/refs/branches/create.c b/tests-clar/refs/branches/create.c
index 9026b0de1..5ecb42848 100644
--- a/tests-clar/refs/branches/create.c
+++ b/tests-clar/refs/branches/create.c
@@ -16,9 +16,13 @@ void test_refs_branches_create__initialize(void)
 void test_refs_branches_create__cleanup(void)
 {
 	git_reference_free(branch);
+	branch = NULL;
 
 	git_object_free(target);
+	target = NULL;
+
 	git_repository_free(repo);
+	repo = NULL;
 
 	cl_fixture_cleanup("testrepo.git");
 }
diff --git a/tests-clar/refs/branches/delete.c b/tests-clar/refs/branches/delete.c
index da7db13fc..75271a21c 100644
--- a/tests-clar/refs/branches/delete.c
+++ b/tests-clar/refs/branches/delete.c
@@ -20,7 +20,10 @@ void test_refs_branches_delete__initialize(void)
 void test_refs_branches_delete__cleanup(void)
 {
 	git_reference_free(fake_remote);
+	fake_remote = NULL;
+
 	git_repository_free(repo);
+	repo = NULL;
 
 	cl_fixture_cleanup("testrepo.git");
 }
diff --git a/tests-clar/refs/branches/foreach.c b/tests-clar/refs/branches/foreach.c
index 92d5b1f65..dfa04395b 100644
--- a/tests-clar/refs/branches/foreach.c
+++ b/tests-clar/refs/branches/foreach.c
@@ -18,7 +18,10 @@ void test_refs_branches_foreach__initialize(void)
 void test_refs_branches_foreach__cleanup(void)
 {
 	git_reference_free(fake_remote);
+	fake_remote = NULL;
+
 	git_repository_free(repo);
+	repo = NULL;
 
 	cl_fixture_cleanup("testrepo.git");
 }
diff --git a/tests-clar/refs/branches/ishead.c b/tests-clar/refs/branches/ishead.c
index 52a0a1941..2ab488f22 100644
--- a/tests-clar/refs/branches/ishead.c
+++ b/tests-clar/refs/branches/ishead.c
@@ -13,7 +13,10 @@ void test_refs_branches_ishead__initialize(void)
 void test_refs_branches_ishead__cleanup(void)
 {
 	git_reference_free(branch);
+	branch = NULL;
+
 	git_repository_free(repo);
+	repo = NULL;
 }
 
 void test_refs_branches_ishead__can_tell_if_a_branch_is_pointed_at_by_HEAD(void)
diff --git a/tests-clar/refs/branches/lookup.c b/tests-clar/refs/branches/lookup.c
index 2aabf9889..d07ed0ed8 100644
--- a/tests-clar/refs/branches/lookup.c
+++ b/tests-clar/refs/branches/lookup.c
@@ -14,8 +14,10 @@ void test_refs_branches_lookup__initialize(void)
 void test_refs_branches_lookup__cleanup(void)
 {
 	git_reference_free(branch);
+	branch = NULL;
 
 	git_repository_free(repo);
+	repo = NULL;
 }
 
 void test_refs_branches_lookup__can_retrieve_a_local_branch(void)
diff --git a/tests-clar/refs/branches/move.c b/tests-clar/refs/branches/move.c
index 042469016..4bf1d69d0 100644
--- a/tests-clar/refs/branches/move.c
+++ b/tests-clar/refs/branches/move.c
@@ -15,6 +15,8 @@ void test_refs_branches_move__initialize(void)
 void test_refs_branches_move__cleanup(void)
 {
 	git_reference_free(ref);
+	ref = NULL;
+
 	cl_git_sandbox_cleanup();
 }
 
diff --git a/tests-clar/refs/branches/tracking.c b/tests-clar/refs/branches/tracking.c
index 9cf435e88..9378ecad5 100644
--- a/tests-clar/refs/branches/tracking.c
+++ b/tests-clar/refs/branches/tracking.c
@@ -14,8 +14,10 @@ void test_refs_branches_tracking__initialize(void)
 void test_refs_branches_tracking__cleanup(void)
 {
 	git_reference_free(branch);
+	branch = NULL;
 
 	git_repository_free(repo);
+	repo = NULL;
 }
 
 void test_refs_branches_tracking__can_retrieve_the_remote_tracking_reference_of_a_local_branch(void)