F release results

Summary

Fixes SegFaults in the retrieve function (and others) which were caused by the too-early deletion of the transaction object by the garbage collector

Focus

The most relevant line is where we call caosdb_transaction_result_set_release_at instead of caosdb_transaction_result_set_at and release the entity from the result set.

Test Environment

Integration caosdb-juliainttest!7 (merged)

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• All automated tests pass
• Reference related Issues
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  • Intent of new code
  • Problems with old code
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Check List for the Reviewer

• I understand the intent of this MR
• All automated tests pass
• Up-to-date CHANGELOG.md
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src/Transaction.jl

@@ -433,6 +433,46 @@ function get_result_at(results::Ref{_ResultSet}, index::Cint)
     return entity
 end
 
+"""
+    function _release_result_at(results::Ref{_ResultSet}, index::Cint)
+
+Return the entity at position `index` of the given `results`.
+
+This function releases the entity from the result set and leaves the result set
+in a corrupted state. It should only be used to release the entity from a
+result set which is about to be destroyed anyway.
+"""
+function _release_result_at(results::Ref{_ResultSet}, index::Cint)
+
+    size = get_result_size(results)
+
+    if index > size
+        throw(
+            DomainError(
+                index,
+                "You tried to access the result at position $index but the result set only has $size results.",
+            ),
+        )
+    end
+
+    entity = Ref{CaosDB.Entity._Entity}(CaosDB.Entity._Entity())
+
+    err_code = ccall(
+        # TODO (fspreck) this is the only difference to get_result_at(...). Is
+        # there a smart way to reduce the code duplication here?
+        (:caosdb_transaction_result_set_release_at, CaosDB.library_name),
+        Cint,
+        (Ref{_ResultSet}, Ref{CaosDB.Entity._Entity}, Cint),
+        results,
+        entity,
+        index - Cint(1),
+    )
+
+    CaosDB.Exceptions.evaluate_return_code(err_code)
+
+    return entity
+end
+
 """
     function get_result_at(results::Ref{_ResultSet}, index::Integer)
 
@@ -448,7 +488,7 @@ end
 """
     function get_results(result_set::Ref{_ResultSet})
 
-Return al  results of the given `result_set`.
+Return all entities of the given `result_set`.
 """
 function get_results(result_set::Ref{_ResultSet})
 
@@ -469,6 +509,39 @@ function get_results(transaction::Ref{_Transaction})
     return get_results(result_set)
 end
 
+"""
+    function _release_results(transaction::Ref{_Transaction})
+
+Return all results fo the given `transaction`.
+
+This function also leaves the transaction object in a corrupted state and
+should only be used to release the results from a transaction which is about to
+be destroyed anyway.
+"""
+function _release_results(transaction::Ref{_Transaction})
+
+    result_set = get_result_set(transaction)
+
+    return _release_results(result_set)
+end
+
+"""
+    function _release_results(result_set::Ref{_ResultSet})
+
+Return all entities of the given `result_set`.
+
+This function also leaves the result_set object in a corrupted state and
+should only be used to release the entities from a result_set which is about to
+be destroyed anyway.
+"""
+function _release_results(result_set::Ref{_ResultSet})
+
+    size = get_result_size(result_set)
+
+    return [_release_result_at(result_set, Cint(ii)) for ii = 1:size]
+end
+
+
 """
     function execute_query(
         query::AbstractString,
@@ -495,7 +568,7 @@ function execute_query(query::AbstractString, name::AbstractString = "default")
 
     execute(transaction)
 
-    return get_results(transaction)
+    return _release_results(transaction)
 end
 
 """
@@ -526,7 +599,7 @@ function execute_query(
 
     execute(transaction)
 
-    return get_results(transaction)
+    return _release_results(transaction)
 end
 
 """
@@ -544,7 +617,7 @@ function retrieve(id::AbstractString, name::AbstractString = "default")
 
     execute(transaction)
 
-    return get_results(transaction)[1]
+    return _release_results(transaction)[1]
 end
 
 """
@@ -561,7 +634,7 @@ function retrieve(id::AbstractString, connection::Ref{CaosDB.Connection._Connect
 
     execute(transaction)
 
-    return get_results(transaction)[1]
+    return _release_results(transaction)[1]
 end
 
 """
@@ -585,7 +658,7 @@ function retrieve(
 
     execute(transaction)
 
-    return get_results(transaction)
+    return _release_results(transaction)
 end
 
 """
@@ -608,7 +681,7 @@ function retrieve(
 
     execute(transaction)
 
-    return get_results(transaction)
+    return _release_results(transaction)
 end
 """
     function insert_entity(entity::Ref{CaosDB.Entity._Entity})
@@ -620,7 +693,7 @@ function insert_entity(entity::Ref{CaosDB.Entity._Entity})
     transaction = create_transaction()
     add_insert_entity(transaction, entity)
     execute(transaction)
-    return get_results(transaction)
+    return _release_results(transaction)
 end
 """
     function update_entity(entity::Ref{CaosDB.Entity._Entity})
@@ -632,7 +705,7 @@ function update_entity(entity::Ref{CaosDB.Entity._Entity})
     transaction = create_transaction()
     add_update_entity(transaction, entity)
     execute(transaction)
-    return get_results(transaction)
+    return _release_results(transaction)
 end
 """
     function delete_by_id(id::AbstractString)
@@ -644,7 +717,7 @@ function delete_by_id(id::AbstractString)
     transaction = create_transaction()
     add_delete_by_id(transaction, id)
     execute(transaction)
-    return get_results(transaction)
+    return _release_results(transaction)
 end
 """
     function retrieve_and_download_file_by_id(
@@ -659,7 +732,7 @@ function retrieve_and_download_file_by_id(id::AbstractString, download_path::Abs
     transaction = create_transaction()
     add_retrieve_and_download_file_by_id(transaction, id, download_path)
     execute(transaction)
-    return get_results(transaction)
+    return _release_results(transaction)
 end
 
 end # Transaction