[patches] [PATCH] sql: disallow id duplicate in insert & update

[AKhatskevich]

## branch https://github.com/tarantool/tarantool/tree/kh/gh-2358-insert-stmt-duplicate
## issue https://github.com/tarantool/tarantool/issues/2358

Before this patch one was able to exec query like this:
  `insert into t(col1, col1) values(1, 1)`
  `update t set col1 = 1, col1 = 2;`
which is nonsense.

New policy is to throw an error in case of duplicates in columns
description.

The fix for insert compares each identifier with the others and
therefore has O(n^2) complexity. However, it seems that to maintain
faster data structure just for this small check is redundant.

The fix for update takes O(n), because it is implemented on initialized
array.

Closes #2358
---
 src/box/sql/insert.c          | 10 ++++++++++
 src/box/sql/update.c          |  7 +++++++
 test/sql-tap/insert1.test.lua | 30 +++++++++++++++++++++++++++++-
 test/sql-tap/update.test.lua  | 23 ++++++++++++++++++++++-
 4 files changed, 68 insertions(+), 2 deletions(-)

diff --git a/src/box/sql/insert.c b/src/box/sql/insert.c
index 947c262e2..0a6437005 100644
--- a/src/box/sql/insert.c
+++ b/src/box/sql/insert.c
@@ -477,6 +477,16 @@ sqlite3Insert(Parse * pParse,	/* Parser context */
 				pParse->checkSchema = 1;
 				goto insert_cleanup;
 			}
+			for (j = 0; j < i; j++) {
+				if (pColumn->a[j].idx != pColumn->a[i].idx)
+					continue;
+				const char *err;
+				err = "table id list: duplicate column name %s";
+				sqlite3ErrorMsg(pParse,
+						err,
+						pColumn->a[i].zName);
+				goto insert_cleanup;
+			}
 		}
 	}
 
diff --git a/src/box/sql/update.c b/src/box/sql/update.c
index 47500ec9e..8f35f472b 100644
--- a/src/box/sql/update.c
+++ b/src/box/sql/update.c
@@ -233,6 +233,13 @@ sqlite3Update(Parse * pParse,		/* The parser context */
 				if (pPk && table_column_is_in_pk(pTab, j)) {
 					chngPk = 1;
 				}
+				if (aXRef[j] != -1) {
+					sqlite3ErrorMsg(pParse,
+							"set id list: duplicate"
+							" column name %s",
+							pChanges->a[i].zName);
+					goto update_cleanup;
+				}
 				aXRef[j] = i;
 				break;
 			}
diff --git a/test/sql-tap/insert1.test.lua b/test/sql-tap/insert1.test.lua
index 847b25ad2..750732d37 100755
--- a/test/sql-tap/insert1.test.lua
+++ b/test/sql-tap/insert1.test.lua
@@ -1,7 +1,7 @@
 #!/usr/bin/env tarantool
 test = require("sqltester")
 yaml = require('yaml')
-test:plan(24)
+test:plan(28)
 
 --!./tcltestrunner.lua
 -- 2001 September 15
@@ -516,5 +516,33 @@ test:do_execsql_test("insert-4.7", [[
 --   SELECT * FROM t12c;
 -- } {one xyzzy two}
 -- integrity_check insert-99.0
+
+
+test:do_execsql_test(
+    "insert-13.0",
+    [[
+        create table test(a primary key, b)
+    ]])
+
+test:do_catchsql_test(
+    "insert-13.1",
+    [[
+        insert into test(a, a, b) values(1, 1, 1)
+    ]],
+    {1, "table id list: duplicate column name A"})
+
+test:do_catchsql_test(
+    "insert-13.2",
+    [[
+        insert into test(a, b, b) values(1, 1, 1)
+    ]],
+    {1, "table id list: duplicate column name B"})
+
+test:do_execsql_test(
+    "insert-13.3",
+    [[
+        drop table test;
+    ]])
+
 test:finish_test()
 
diff --git a/test/sql-tap/update.test.lua b/test/sql-tap/update.test.lua
index f6e756731..a4efe4015 100755
--- a/test/sql-tap/update.test.lua
+++ b/test/sql-tap/update.test.lua
@@ -1,6 +1,6 @@
 #!/usr/bin/env tarantool
 test = require("sqltester")
-test:plan(108)
+test:plan(111)
 
 --!./tcltestrunner.lua
 -- 2001 September 15
@@ -1109,5 +1109,26 @@ test:do_catchsql_test("update-10.10", [[
 --   UPDATE t15 SET c=printf("y%d",a) WHERE c IS NULL;
 --   SELECT a,b,c,'|' FROM t15 ORDER BY a;
 -- } {5 zyx y5 | 10 abc y10 | 15 wvu y15 | 20 def y20 | 25 tsr y25 | 30 ghi y30 | 35 qpo y35 |}
+
+test:do_execsql_test(
+    "insert-15.0",
+    [[
+        create table test(a primary key);
+        insert into test(a) values(1);
+    ]])
+
+test:do_catchsql_test(
+    "insert-15.1",
+    [[
+        update test set a = 2, a = 3;
+    ]],
+    {1, "set id list: duplicate column name A"})
+
+test:do_execsql_test(
+  "insert-15.2",
+  [[
+      drop table test;
+  ]])
+
 test:finish_test()
 
-- 
2.14.1