Backport #86171 to 25.8: Fix use-of-unitialized-value and crash introduced in #85063

robot-clickhouse · robot-clickhouse · commit 8570e42a168d · 2025-08-26T19:10:33.000Z
diff --git a/src/Functions/ReplaceStringImpl.h b/src/Functions/ReplaceStringImpl.h
@@ -354,7 +354,7 @@ struct ReplaceStringImpl
             res_data.assign(haystack_data.begin(), haystack_data.end());
             res_offsets.resize(input_rows_count);
             for (size_t i = 1; i <= input_rows_count; ++i)
-                res_offsets[i] = i * n;
+                res_offsets[i - 1] = i * n;
             return;
         }
 
diff --git a/src/Functions/URL/domain.h b/src/Functions/URL/domain.h
@@ -172,7 +172,7 @@ inline std::string_view getURLHost(const char * data, size_t size)
     Pos pos = data;
     Pos end = data + size;
 
-    if (*pos == '/' && *(pos + 1) == '/')
+    if (size >= 2 && *pos == '/' && *(pos + 1) == '/')
     {
         pos += 2;
     }
diff --git a/tests/queries/0_stateless/03600_replace_fixed_string_bug.reference b/tests/queries/0_stateless/03600_replace_fixed_string_bug.reference
@@ -0,0 +1 @@
+a
diff --git a/tests/queries/0_stateless/03600_replace_fixed_string_bug.sql b/tests/queries/0_stateless/03600_replace_fixed_string_bug.sql
@@ -0,0 +1,2 @@
+SELECT replace(materialize(toFixedString('a', 1)), '', '');
+

Original file line number	Diff line number	Diff line change
`@@ -354,7 +354,7 @@ struct ReplaceStringImpl`
`354`	`354`	`res_data.assign(haystack_data.begin(), haystack_data.end());`
`355`	`355`	`res_offsets.resize(input_rows_count);`
`356`	`356`	`for (size_t i = 1; i <= input_rows_count; ++i)`
`357`		`- res_offsets[i] = i * n;`
	`357`	`+ res_offsets[i - 1] = i * n;`
`358`	`358`	`return;`
`359`	`359`	`}`
`360`	`360`
Original file line number	Diff line number	Diff line change
`@@ -172,7 +172,7 @@ inline std::string_view getURLHost(const char * data, size_t size)`
`172`	`172`	`Pos pos = data;`
`173`	`173`	`Pos end = data + size;`
`174`	`174`
`175`		`- if (pos == '/' && (pos + 1) == '/')`
	`175`	`+ if (size >= 2 && pos == '/' && (pos + 1) == '/')`
`176`	`176`	`{`
`177`	`177`	`pos += 2;`
`178`	`178`	`}`
Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,2 @@`
	`1`	`+SELECT replace(materialize(toFixedString('a', 1)), '', '');`
	`2`	`+`