test: align space_index_test with the transactional DDL

CHANGELOG.md

@@ -11,6 +11,10 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 
 ### Changed
 
+- Updated the 'space_index_test.lua' to drop and recreate the test space
+  atomically. This prevents the space access failure in the expirationd
+  task fiber if the `space:drop` function is transactional (#157).
+
 ### Fixed
 
 ## 1.5.0 - 2023-08-23

test/helper.lua

@@ -287,6 +287,19 @@ function helpers.memtx_func_index_is_supported()
         (major >= 3)
 end
 
+function helpers.single_yield_transactional_ddl_is_supported()
+    local major, minor, patch = helpers.tarantool_version()
+
+    -- The issue: https://github.com/tarantool/tarantool/issues/4083
+    --
+    -- A limited transactional DDL support has been introduced in 2.2.1, it
+    -- allows to wrap a single-yield DDL statement set into a transaction if
+    -- the yielding statement is the first in the transaction.
+    return (major == 2 and minor == 2 and patch >= 1) or
+        (major == 2 and minor >= 3) or
+        (major >= 3)
+end
+
 function helpers.error_function()
     error("error function call")
 end

test/unit/space_index_test.lua

@@ -348,9 +348,39 @@ function g.test_not_stop_after_drop_and_recreate(cg)
     end)
 
     helpers.iteration_result = {}
+
+    -- This should be atomic to prevent yielding into the expirationd task with
+    -- partially applied changes (when the old space is dropped but the new one
+    -- is not created yet).
+    --
+    -- The space drop is transactional if the tarantool/taratool#8751 is merged,
+    -- so it yields on commit. After that point the space is dropped.
+    --
+    -- The expirationd task yields on each tuple drop if the task does not have
+    -- the atomic_iteration option set.
+    --
+    -- So without this begin/commit guard the following situation is possible:
+    -- 1. The expirationd task has started.
+    -- 2. The task removes one tuple, which causes yield.
+    -- 3. The current fiber drops the space and yields to the expirationd task.
+    -- 4. The expirationd task finishes the iteration and checks if the space
+    --    is vinyl to update the vinyl_assumed_space_len, but the space does
+    --    not exist anymore, so it fails causing the task restart.
+
+    -- Since the test is also executed against old versions of Tarantool, let's
+    -- only wrap the space drop and recreation into transaction on the versions
+    -- that support at least single-yield transactional DDL.
+    if helpers.single_yield_transactional_ddl_is_supported() then
+        box.begin()
+    end
+
     cg.case_space:drop()
     create_case_space(cg, space_name)
 
+    if helpers.single_yield_transactional_ddl_is_supported() then
+        box.commit()
+    end
+
     helpers.retrying({}, function()
         t.assert_equals(helpers.iteration_result, {{2, "2"}})
     end)