Fix bug in Fortran dataset destructor

doc/changelog.md

@@ -6,6 +6,7 @@ To be released at a future time.
 
 Description
 
+-  Fix a segfault in the dataset destructor
 -  Update supported Python versions to 3.10, 3.11, and 3.12
 -  Bump versions for upload/download-artifact Github Actions
 -  Add Client API functions to put, get, unpack,
@@ -15,8 +16,16 @@ Description
 -  Reenable move semantics and fix compiler warnings.
 
 Detailed Notes
-
-- Update supported Python versions to 3.10, 3.11, and 3.12
+-  For compilers that automatically call the dataset
+   destructor when the object goes out of scope, a segfault
+   was being triggered if the user was also explictly calling
+   the destructor. This was partially arising because
+   although we were freeing the underlying data and pointing to
+   NULL, the pointer to the object itself was never being
+   set to NULL. This has been fixed and should now be robust
+   to multiple calls to the destructor.
+   ([PR525](https://github.com/CrayLabs/SmartRedis/pull/525))
+-  Update supported Python versions to 3.10, 3.11, and 3.12
    ([PR527](https://github.com/CrayLabs/SmartRedis/pull/527))
 -  Bump versions for upload/download-artifact Github Actions
    ([PR526](https://github.com/CrayLabs/SmartRedis/pull/526))

src/c/c_dataset.cpp

@@ -95,6 +95,7 @@ extern "C" SRError DeallocateDataSet(void** dataset)
     DataSet* d = reinterpret_cast<DataSet*>(*dataset);
     delete d;
     *dataset = NULL;
+    dataset = NULL;
   });
 }
 

src/fortran/dataset.F90

@@ -153,7 +153,7 @@ subroutine final_destructor(self)
   type(dataset_type), intent(inout) :: self
   integer :: code
 
-  if (c_associated(self%dataset_ptr)) code = dataset_deconstructor(self%dataset_ptr)
+  code = self%destructor()
 end subroutine final_destructor
 
 !> Destroy the dataset

tests/fortran/client_test_dataset.F90

@@ -73,7 +73,7 @@ program main
   integer :: ndims
 
   integer :: i, j, k
-  type(dataset_type) :: dataset
+  type(dataset_type) :: dataset, retrieved_dataset
   type(client_type) :: client
 
   integer :: err_code
@@ -239,6 +239,11 @@ program main
   if (result .ne. SRNoError) error stop
   if (.not. exists) error stop 'existent dataset: FAILED'
 
+  ! Test retrieval of dataset
+  result = client%get_dataset("test_dataset", retrieved_dataset)
+  if (result .ne. SRNoError) error stop
+  if (.not. exists) error stop 'get_dataset: FAILED'
+
 
   write(*,*) "Fortran Dataset: passed"