This patch fixes the problem with copying an empty string in mem_copy().
Previously, because the string length was 0, an error was thrown, but
the diag was not set, which could lead to an error due to an empty diag
or to a double free.
Closes #6157
---
https://github.com/tarantool/tarantool/issues/6157
https://github.com/tarantool/tarantool/tree/imeevma/gh-6157-fix-error-on-empty-str
.../gh-6157-fix-error-on-copy-empty-str.md | 5 +++
src/box/sql/mem.c | 3 +-
test/sql-tap/CMakeLists.txt | 1 +
test/sql-tap/engine.cfg | 1 +
.../gh-6157-unnecessary-free-on-string.c | 10 +++++
...h-6157-unnecessary-free-on-string.test.lua | 38 +++++++++++++++++++
6 files changed, 57 insertions(+), 1 deletion(-)
create mode 100644 changelogs/unreleased/gh-6157-fix-error-on-copy-empty-str.md
create mode 100644 test/sql-tap/gh-6157-unnecessary-free-on-string.c
create mode 100755 test/sql-tap/gh-6157-unnecessary-free-on-string.test.lua
diff --git a/changelogs/unreleased/gh-6157-fix-error-on-copy-empty-str.md b/changelogs/unreleased/gh-6157-fix-error-on-copy-empty-str.md
new file mode 100644
index 000000000..e5f747414
--- /dev/null
+++ b/changelogs/unreleased/gh-6157-fix-error-on-copy-empty-str.md
@@ -0,0 +1,5 @@
+## bugfix/sql
+
+* Now, when copying an empty string, an error will not be set
+ unnecessarily (gh-6157).
+
diff --git a/src/box/sql/mem.c b/src/box/sql/mem.c
index 0aca76112..c91fc8396 100644
--- a/src/box/sql/mem.c
+++ b/src/box/sql/mem.c
@@ -1913,7 +1913,8 @@ mem_copy(struct Mem *to, const struct Mem *from)
assert((to->flags & MEM_Zero) == 0 || to->type == MEM_TYPE_BIN);
if ((to->flags & MEM_Zero) != 0)
return sqlVdbeMemExpandBlob(to);
- to->zMalloc = sqlDbReallocOrFree(to->db, to->zMalloc, to->n);
+ to->zMalloc = sqlDbRealloc(to->db, to->zMalloc, MAX(32, to->n));
+ assert(to->zMalloc != NULL || sql_get()->mallocFailed != 0);
if (to->zMalloc == NULL)
return -1;
to->szMalloc = sqlDbMallocSize(to->db, to->zMalloc);
diff --git a/test/sql-tap/CMakeLists.txt b/test/sql-tap/CMakeLists.txt
index 87f23b2f7..2e215032b 100644
--- a/test/sql-tap/CMakeLists.txt
+++ b/test/sql-tap/CMakeLists.txt
@@ -3,3 +3,4 @@ build_module(gh-5938-wrong-string-length gh-5938-wrong-string-length.c)
build_module(gh-6024-funcs-return-bin gh-6024-funcs-return-bin.c)
build_module(sql_uuid sql_uuid.c)
build_module(decimal decimal.c)
+build_module(gh-6157 gh-6157-unnecessary-free-on-string.c)
diff --git a/test/sql-tap/engine.cfg b/test/sql-tap/engine.cfg
index 35754f769..f6f7752af 100644
--- a/test/sql-tap/engine.cfg
+++ b/test/sql-tap/engine.cfg
@@ -35,6 +35,7 @@
"built-in-functions.test.lua": {
"memtx": {"engine": "memtx"}
},
+ "gh-6157-unnecessary-free-on-string.test.lua": {},
"gh-4077-iproto-execute-no-bind.test.lua": {},
"*": {
"memtx": {"engine": "memtx"},
diff --git a/test/sql-tap/gh-6157-unnecessary-free-on-string.c b/test/sql-tap/gh-6157-unnecessary-free-on-string.c
new file mode 100644
index 000000000..ce928d494
--- /dev/null
+++ b/test/sql-tap/gh-6157-unnecessary-free-on-string.c
@@ -0,0 +1,10 @@
+#include "msgpuck.h"
+#include "module.h"
+
+int
+f(box_function_ctx_t* ctx, const char* args, const char* args_end)
+{
+ char res[16];
+ char *end = mp_encode_str(res, "stub", strlen("stub"));
+ return box_return_mp(ctx, res, end);
+}
diff --git a/test/sql-tap/gh-6157-unnecessary-free-on-string.test.lua b/test/sql-tap/gh-6157-unnecessary-free-on-string.test.lua
new file mode 100755
index 000000000..326570aea
--- /dev/null
+++ b/test/sql-tap/gh-6157-unnecessary-free-on-string.test.lua
@@ -0,0 +1,38 @@
+#!/usr/bin/env tarantool
+local build_path = os.getenv("BUILDDIR")
+package.cpath = build_path..'/test/sql-tap/?.so;'..build_path..'/test/sql-tap/?.dylib;'..package.cpath
+
+local test = require("sqltester")
+test:plan(1)
+
+box.schema.func.create("gh-6157.f", {
+ language = "C",
+ param_list = {"string"},
+ returns = "string",
+ exports = {"SQL"}
+})
+
+box.execute([[CREATE TABLE ts(s STRING PRIMARY KEY);]])
+box.execute([[INSERT INTO ts VALUES ('');]])
+box.execute([[CREATE TABLE ti(i INT PRIMARY KEY);]])
+for i = 1, 100 do
+ box.execute([[INSERT INTO ti VALUES(]]..i..[[);]])
+end
+
+test:do_execsql_test(
+ "gh-6157",
+ [[
+ SELECT COUNT("gh-6157.f"('')), (SELECT s FROM ts WHERE s = '') FROM ti;
+ SELECT COUNT("gh-6157.f"('')), (SELECT s FROM ts WHERE s = '') FROM ti;
+ SELECT COUNT("gh-6157.f"('')), (SELECT s FROM ts WHERE s = '') FROM ti;
+ SELECT COUNT("gh-6157.f"('')), (SELECT s FROM ts WHERE s = '') FROM ti;
+ SELECT COUNT("gh-6157.f"('')), (SELECT s FROM ts WHERE s = '') FROM ti;
+ ]], {
+ 100, ""
+ })
+
+box.space._func.index['name']:delete("gh-6157.f")
+box.execute([[DROP TABLE ts;]])
+box.execute([[DROP TABLE ti;]])
+
+test:finish_test()
--
2.25.1