[Tarantool-patches] [PATCH v1 1/1] sql: fix comparison between big DOUBLE and DECIMAL

[Mergen Imeev]

Hi! Thank you for the review! I fixed test and made some changes in
descriprions. Diff and new patch below.

On Thu, Aug 26, 2021 at 10:15:31PM +0200, Vladislav Shpilevoy wrote:
> Hi! Thanks for the patch!
> 
> The new test passes even without the changes in mem.c.


Diff:


diff --git a/changelogs/unreleased/gh-6376-fix-incorrect-dec-inf-cmp.md b/changelogs/unreleased/gh-6376-fix-incorrect-dec-inf-cmp.md
index 102b6b9ab..70de655f1 100644
--- a/changelogs/unreleased/gh-6376-fix-incorrect-dec-inf-cmp.md
+++ b/changelogs/unreleased/gh-6376-fix-incorrect-dec-inf-cmp.md
@@ -1,5 +1,3 @@
 ## bugfix/sql
 
-* Fixed wrong comparison between inf and -inf DOUBLE values and DECIMAL
-  values (gh-6376).
-
+* Fixed wrong comparison between DECIMAL and large DOUBLE values (gh-6376).
diff --git a/test/sql-tap/gh-6376-wrong-double-to-dec-cmp.test.lua b/test/sql-tap/gh-6376-wrong-double-to-dec-cmp.test.lua
index 8066e365b..edfc851a2 100755
--- a/test/sql-tap/gh-6376-wrong-double-to-dec-cmp.test.lua
+++ b/test/sql-tap/gh-6376-wrong-double-to-dec-cmp.test.lua
@@ -2,14 +2,11 @@
 local test = require("sqltester")
 test:plan(4)
 
---
--- Make sure that the comparison between too large or too small DOUBLE and
--- DECIMAL is correct.
---
+-- Make sure that the comparison between DECIMAL and large DOUBLE is correct.
 test:do_execsql_test(
     "gh-6376-1",
     [[
-        SELECT -1e40 > CAST(1 AS DECIMAL);
+        SELECT CAST(1 AS DECIMAL) < -1e40;
     ]], {
         false
     })
@@ -17,7 +14,7 @@ test:do_execsql_test(
 test:do_execsql_test(
     "gh-6376-2",
     [[
-        SELECT -1e400 < CAST(-1 AS DECIMAL);
+        SELECT CAST(-1 AS DECIMAL) > -1e400;
     ]], {
         true
     })
@@ -25,7 +22,7 @@ test:do_execsql_test(
 test:do_execsql_test(
     "gh-6376-3",
     [[
-        SELECT 1e40 >= CAST(1 AS DECIMAL);
+        SELECT CAST(1 AS DECIMAL) <= 1e40;
     ]], {
         true
     })
@@ -33,7 +30,7 @@ test:do_execsql_test(
 test:do_execsql_test(
     "gh-6376-4",
     [[
-        SELECT 1e400 <= CAST(1 AS DECIMAL);
+        SELECT CAST(1 AS DECIMAL) >= 1e400;
     ]], {
         false
     })



New patch:


commit 710054a586ca94cf3a8db67fdfb3530ffdf1153d
Author: Mergen Imeev <imeevma at gmail.com>
Date:   Mon Aug 23 09:34:23 2021 +0300

    sql: fix comparison between DECIMAL and big DOUBLE
    
    This patch fixes comparison between DECIMAL value and DOUBLE values
    greater or equal to 1e38 or less or equal to -1e38. Now any DOUBLE value
    greater or equal to 1e38 is more than any DECIMAL value and DOUBLE
    value less or equal to -1e38 is less than any DECIMAL value.
    
    Closes #6376

diff --git a/changelogs/unreleased/gh-6376-fix-incorrect-dec-inf-cmp.md b/changelogs/unreleased/gh-6376-fix-incorrect-dec-inf-cmp.md
new file mode 100644
index 000000000..70de655f1
--- /dev/null
+++ b/changelogs/unreleased/gh-6376-fix-incorrect-dec-inf-cmp.md
@@ -0,0 +1,3 @@
+## bugfix/sql
+
+* Fixed wrong comparison between DECIMAL and large DOUBLE values (gh-6376).
diff --git a/src/box/sql/mem.c b/src/box/sql/mem.c
index 0aca76112..fbfe81038 100644
--- a/src/box/sql/mem.c
+++ b/src/box/sql/mem.c
@@ -2451,9 +2451,9 @@ mem_cmp_num(const struct Mem *a, const struct Mem *b)
 		}
 		case MEM_TYPE_DOUBLE: {
 			if (b->u.r >= 1e38)
-				return 1;
-			if (b->u.r <= -1e38)
 				return -1;
+			if (b->u.r <= -1e38)
+				return 1;
 			decimal_t dec;
 			decimal_t *d = decimal_from_double(&dec, b->u.r);
 			assert(d != NULL && d == &dec);
diff --git a/test/sql-tap/engine.cfg b/test/sql-tap/engine.cfg
index 35754f769..26d85b674 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-6376-wrong-double-to-dec-cmp.test.lua": {},
     "gh-4077-iproto-execute-no-bind.test.lua": {},
     "*": {
         "memtx": {"engine": "memtx"},
diff --git a/test/sql-tap/gh-6376-wrong-double-to-dec-cmp.test.lua b/test/sql-tap/gh-6376-wrong-double-to-dec-cmp.test.lua
new file mode 100755
index 000000000..edfc851a2
--- /dev/null
+++ b/test/sql-tap/gh-6376-wrong-double-to-dec-cmp.test.lua
@@ -0,0 +1,38 @@
+#!/usr/bin/env tarantool
+local test = require("sqltester")
+test:plan(4)
+
+-- Make sure that the comparison between DECIMAL and large DOUBLE is correct.
+test:do_execsql_test(
+    "gh-6376-1",
+    [[
+        SELECT CAST(1 AS DECIMAL) < -1e40;
+    ]], {
+        false
+    })
+
+test:do_execsql_test(
+    "gh-6376-2",
+    [[
+        SELECT CAST(-1 AS DECIMAL) > -1e400;
+    ]], {
+        true
+    })
+
+test:do_execsql_test(
+    "gh-6376-3",
+    [[
+        SELECT CAST(1 AS DECIMAL) <= 1e40;
+    ]], {
+        true
+    })
+
+test:do_execsql_test(
+    "gh-6376-4",
+    [[
+        SELECT CAST(1 AS DECIMAL) >= 1e400;
+    ]], {
+        false
+    })
+
+test:finish_test()