[tarantool-patches] [PATCH] box: add a method to check if transaction is open

[Roman Khabibov <roman.habibov1@yandex.ru>]

Add method box.is_in_txn()

Closes: #3518.
---
Branch: https://github.com/tarantool/tarantool/tree/romankhabibov/gh-3518-check-if-txn
Issue: https://github.com/tarantool/tarantool/issues/3518

 extra/exports                 |  1 +
 src/box/lua/schema.lua        |  6 ++++++
 src/box/txn.c                 |  6 ++++++
 src/box/txn.h                 |  8 ++++++++
 test/box/misc.result          |  1 +
 test/box/transaction.result   | 18 ++++++++++++++++++
 test/box/transaction.test.lua |  8 ++++++++
 test/engine/savepoint.result  | 12 ++++++------
 8 files changed, 54 insertions(+), 6 deletions(-)

diff --git a/extra/exports b/extra/exports
index 319d2c4..2f408d9 100644
--- a/extra/exports
+++ b/extra/exports
@@ -136,6 +136,7 @@ luaT_state
 luaT_tolstring
 box_txn
 box_txn_begin
+box_is_in_txn
 box_txn_commit
 box_txn_savepoint
 box_txn_rollback
diff --git a/src/box/lua/schema.lua b/src/box/lua/schema.lua
index 74b7064..e1526ac 100644
--- a/src/box/lua/schema.lua
+++ b/src/box/lua/schema.lua
@@ -68,6 +68,8 @@ ffi.cdef[[
     box_txn_id();
     int
     box_txn_begin();
+    bool
+    box_is_in_txn();
     /** \endcond public */
     typedef struct txn_savepoint box_txn_savepoint_t;
 
@@ -321,6 +323,10 @@ box.begin = function()
     end
 end
 
+box.is_in_txn = function()
+    return { builtin.box_is_in_txn() }
+end
+
 box.savepoint = function()
     local csavepoint = builtin.box_txn_savepoint()
     if csavepoint == nil then
diff --git a/src/box/txn.c b/src/box/txn.c
index 617ceb8..51b50bf 100644
--- a/src/box/txn.c
+++ b/src/box/txn.c
@@ -447,6 +447,12 @@ box_txn_begin()
 	return 0;
 }
 
+bool
+box_is_in_txn()
+{
+	return box_txn();
+}
+
 int
 box_txn_commit()
 {
diff --git a/src/box/txn.h b/src/box/txn.h
index e74c14d..e587129 100644
--- a/src/box/txn.h
+++ b/src/box/txn.h
@@ -382,6 +382,14 @@ API_EXPORT int
 box_txn_commit(void);
 
 /**
+ * Check if transaction opened in the current fiber.
+ * @retval true Transaction is opened.
+ * @retval false Transaction is closed.
+ */
+API_EXPORT bool
+box_is_in_txn(void);
+
+/**
  * Rollback the current transaction.
  * May fail if called from a nested
  * statement.
diff --git a/test/box/misc.result b/test/box/misc.result
index d9f8d4e..325af3b 100644
--- a/test/box/misc.result
+++ b/test/box/misc.result
@@ -67,6 +67,7 @@ t
   - index
   - info
   - internal
+  - is_in_txn
   - on_commit
   - on_rollback
   - once
diff --git a/test/box/transaction.result b/test/box/transaction.result
index e024084..fb7ebbd 100644
--- a/test/box/transaction.result
+++ b/test/box/transaction.result
@@ -12,6 +12,24 @@ test_run:cmd("setopt delimiter ';'")
 box.begin() box.commit();
 ---
 ...
+-- gh-3518 no active transaction - false
+box.is_in_txn();
+---
+- - false
+...
+-- start transaction
+box.begin();
+---
+...
+-- active transaction - true
+box.is_in_txn();
+---
+- - true
+...
+-- close transaction
+box.commit();
+---
+...
 -- double begin
 box.begin() box.begin();
 ---
diff --git a/test/box/transaction.test.lua b/test/box/transaction.test.lua
index e1d258e..79a2c0b 100644
--- a/test/box/transaction.test.lua
+++ b/test/box/transaction.test.lua
@@ -3,6 +3,14 @@ test_run = env.new()
 test_run:cmd("setopt delimiter ';'")
 -- empty transaction - ok
 box.begin() box.commit();
+-- gh-3518 no active transaction - false
+box.is_in_txn();
+-- start transaction
+box.begin();
+-- active transaction - true
+box.is_in_txn();
+-- close transaction
+box.commit();
 -- double begin
 box.begin() box.begin();
 -- no active transaction since exception rolled it back
diff --git a/test/engine/savepoint.result b/test/engine/savepoint.result
index a62a2e1..00d281b 100644
--- a/test/engine/savepoint.result
+++ b/test/engine/savepoint.result
@@ -14,7 +14,7 @@ s1 = box.savepoint()
 ...
 box.rollback_to_savepoint(s1)
 ---
-- error: 'builtin/box/schema.lua:340: Usage: box.rollback_to_savepoint(savepoint)'
+- error: 'builtin/box/schema.lua:346: Usage: box.rollback_to_savepoint(savepoint)'
 ...
 box.begin() s1 = box.savepoint()
 ---
@@ -323,27 +323,27 @@ test_run:cmd("setopt delimiter ''");
 ok1, errmsg1
 ---
 - false
-- 'builtin/box/schema.lua:340: Usage: box.rollback_to_savepoint(savepoint)'
+- 'builtin/box/schema.lua:346: Usage: box.rollback_to_savepoint(savepoint)'
 ...
 ok2, errmsg2
 ---
 - false
-- 'builtin/box/schema.lua:340: Usage: box.rollback_to_savepoint(savepoint)'
+- 'builtin/box/schema.lua:346: Usage: box.rollback_to_savepoint(savepoint)'
 ...
 ok3, errmsg3
 ---
 - false
-- 'builtin/box/schema.lua:340: Usage: box.rollback_to_savepoint(savepoint)'
+- 'builtin/box/schema.lua:346: Usage: box.rollback_to_savepoint(savepoint)'
 ...
 ok4, errmsg4
 ---
 - false
-- 'builtin/box/schema.lua:340: Usage: box.rollback_to_savepoint(savepoint)'
+- 'builtin/box/schema.lua:346: Usage: box.rollback_to_savepoint(savepoint)'
 ...
 ok5, errmsg5
 ---
 - false
-- 'builtin/box/schema.lua:340: Usage: box.rollback_to_savepoint(savepoint)'
+- 'builtin/box/schema.lua:346: Usage: box.rollback_to_savepoint(savepoint)'
 ...
 s:select{}
 ---
-- 
2.7.4