[release-21.0] Fail assignment expressions with the correct message (#…

…17752) (#17776) Signed-off-by: Manan Gupta <[email protected]> Co-authored-by: Manan Gupta <[email protected]> Co-authored-by: Manan Gupta <[email protected]>
vitessio · Feb 14, 2025 · 6d984ad · 6d984ad
1 parent 312ce23
commit 6d984ad
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diff --git a/go/vt/sqlparser/ast_rewriting.go b/go/vt/sqlparser/ast_rewriting.go
@@ -171,6 +171,9 @@ func (er *astRewriter) rewriteAliasedExpr(node *AliasedExpr) (*BindVarNeeds, err
 
 func (er *astRewriter) rewriteDown(node SQLNode, _ SQLNode) bool {
 	switch node := node.(type) {
+	case *AssignmentExpr:
+		er.err = vterrors.VT12001("Assignment expression")
+		return false
 	case *Select:
 		er.visitSelect(node)
 	case *PrepareStmt, *ExecuteStmt:

diff --git a/go/vt/sqlparser/parse_test.go b/go/vt/sqlparser/parse_test.go
@@ -1327,9 +1327,15 @@ var (
 		input: "update /* a.b */ a.b set b = 3",
 	}, {
 		input: "update a.b set d = @v := d + 7 where u = 42",
+		// Assignment expresions aren't supported, so we skip the normalizer test.
+		// We only support parsing these expressions.
+		ignoreNormalizerTest: true,
 	}, {
 		input:  "select @topic3_id:= 10103;",
 		output: "select @topic3_id := 10103 from dual",
+		// Assignment expresions aren't supported, so we skip the normalizer test.
+		// We only support parsing these expressions.
+		ignoreNormalizerTest: true,
 	}, {
 		input: "update /* list */ a set b = 3, c = 4",
 	}, {

diff --git a/go/vt/vtgate/planbuilder/testdata/unsupported_cases.json b/go/vt/vtgate/planbuilder/testdata/unsupported_cases.json
@@ -229,6 +229,11 @@
     "query": "select @val := 42",
     "plan": "VT12001: unsupported: Assignment expression"
   },
+  {
+    "comment": "Assignment expression in on duplicate clause",
+    "query": "insert into unsharded (id) values (@val := 42)",
+    "plan": "VT12001: unsupported: Assignment expression"
+  },
   {
     "comment": "Assignment expression in union statements",
     "query": "select @val := 42 union select 1",