[tarantool-patches] Re: [PATCH 1/2] sql: fix collation node duplication in AST

[Roman Khabibov <roman.habibov@tarantool.org>]

Hi! Thanks for the review.

> I vote for the second as the simplest, and add a test provided by me
> above to ensure we will never break it accidentally.
> 
> This commit should consist of the test and a comment in resolveAlias.
> And keep this nice ASCII schema.

diff --git a/src/box/sql/resolve.c b/src/box/sql/resolve.c
index 504096e6d..f952d8c04 100644
--- a/src/box/sql/resolve.c
+++ b/src/box/sql/resolve.c
@@ -109,6 +109,11 @@ resolveAlias(Parse * pParse,	/* Parsing context */
 		return;
 	if (zType[0] != 'G')
 		incrAggFunctionDepth(pDup, nSubquery);
+	/*
+	 * If there was typed more than one explicit collations in
+	 * query, it will be a sequence of left nodes with the
+	 * collations in a tree.
+	 */
 	if (pExpr->op == TK_COLLATE) {
 		pDup =
 		    sqlExprAddCollateString(pParse, pDup, pExpr->u.zToken);
diff --git a/test/sql-tap/collation.test.lua b/test/sql-tap/collation.test.lua
index 0bf54576d..3c5d3053a 100755
--- a/test/sql-tap/collation.test.lua
+++ b/test/sql-tap/collation.test.lua
@@ -1,6 +1,6 @@
 #!/usr/bin/env tarantool
 test = require("sqltester")
-test:plan(174)
+test:plan(177)
 
 local prefix = "collation-"
 
@@ -529,4 +529,21 @@ test:do_catchsql_test(
         'CREATE TABLE test3 (a int, b int, c int, PRIMARY KEY (a, a COLLATE foo, b, c))',
         {1, "Collation 'FOO' does not exist"})
 
+-- gh-3805 Check that collation is not ignored. Must pass.
+
+test:do_execsql_test(
+    "collation-2.6.0",
+    [[ CREATE TABLE a (id INT PRIMARY KEY, s TEXT) ]],
+    {})
+
+test:do_execsql_test(
+    "collation-2.6.1",
+    [[ INSERT INTO a VALUES (1, 'B'), (2, 'b') ]],
+    {})
+
+test:do_execsql_test(
+    "collation-2.6.2",
+    [[ SELECT s COLLATE "unicode_ci" FROM a ORDER BY s COLLATE "unicode" ]],
+    {"b","B"})
+
 test:finish_test()