fixed leaking data on rubout

* Objects, that are restored with TECO_DEFINE_UNDO_OBJECT_OWN(),
  could actually leak memory on rubout since the old object was not
  deleted when overwriting it.
* Now that it is, it is crucial to at least nullify objects/pointers
  after calling the corresponding push-function.
  These conditions are now explicitly documented.
* The test suite now runs successfully under Valgrind even with full leak checking.

1 files changed, 2 insertions, 0 deletions

diff --git a/src/qreg.c b/src/qreg.c
index 4beea74..1b97689 100644
--- a/src/qreg.c
+++ b/src/qreg.c
@@ -1708,6 +1708,8 @@ teco_machine_qregspec_auto_complete(teco_machine_qregspec_t *ctx, teco_string_t
 void
 teco_machine_qregspec_free(teco_machine_qregspec_t *ctx)
 {
+	if (!ctx)
+		return;
 	teco_machine_stringbuilding_clear(&ctx->machine_stringbuilding);
 	teco_string_clear(&ctx->name);
 	g_free(ctx);