From adb38aa0ada36ea3b5c3645e2a70466e42cac09f Mon Sep 17 00:00:00 2001
From: wsl-11-2023 <lewfar99@gmail.com>
Date: Sat, 26 Sep 2026 11:07:52 +0100
Subject: [PATCH] Fix ParamRef.Number always 0 for $N bind parameters
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

parserLexer.Lex() copies lexer token data into the yacc semantic
value via a switch on token type, but had no case for PARAM ($1, $2,
...). The lexer (Lexer.lexParam) correctly scans the parameter's
number into Token.Ival, but without a matching case it fell through
to default, which only ever sets lval.str — so lval.ival stayed at
its zero value and every ParamRef parsed with Number 0 regardless of
its actual position in the query.

Adds a case copying tok.Ival into lval.ival, plus a regression test
covering repeated/multiple parameters in both the target list and a
WHERE clause.
---
 parser/parse.go                    |  6 +++
 parser/parsertest/paramref_test.go | 63 ++++++++++++++++++++++++++++++
 2 files changed, 69 insertions(+)
 create mode 100644 parser/parsertest/paramref_test.go

diff --git a/parser/parse.go b/parser/parse.go
index 89c2fcb..1bb45d9 100644
--- a/parser/parse.go
+++ b/parser/parse.go
@@ -74,6 +74,12 @@ func (l *parserLexer) Lex(lval *pgSymType) int {
 		lval.str = tok.Str
 	case ICONST:
 		lval.ival = tok.Ival
+	case PARAM:
+		// The PARAM token ($1, $2, ...) carries its number in Token.Ival
+		// (see Lexer.lexParam), but this switch never copied it into lval,
+		// so every ParamRef parsed with Number 0 regardless of its actual
+		// position.
+		lval.ival = tok.Ival
 	case FCONST, SCONST, BCONST, XCONST:
 		lval.str = tok.Str
 	case Op:
diff --git a/parser/parsertest/paramref_test.go b/parser/parsertest/paramref_test.go
new file mode 100644
index 0000000..5900603
--- /dev/null
+++ b/parser/parsertest/paramref_test.go
@@ -0,0 +1,63 @@
+package parsertest
+
+import (
+	"testing"
+
+	"github.com/pgplex/pgparser/nodes"
+	"github.com/pgplex/pgparser/parser"
+)
+
+// Regression test: parserLexer.Lex() had no case for the PARAM token in its
+// switch that copies lexer token data into the yacc semantic value, so
+// lval.ival was never set for a bind parameter even though the lexer itself
+// (Lexer.lexParam) scans its number correctly. Every $N parsed with
+// ParamRef.Number == 0 regardless of its actual position.
+func TestParseParamRefNumber(t *testing.T) {
+	input := "SELECT $1, $2 FROM t WHERE id = $1"
+
+	result, err := parser.Parse(input)
+	if err != nil {
+		t.Fatalf("Parse error: %v", err)
+	}
+	if result == nil || len(result.Items) != 1 {
+		t.Fatal("expected 1 statement")
+	}
+
+	stmt, ok := result.Items[0].(*nodes.SelectStmt)
+	if !ok {
+		t.Fatalf("expected *nodes.SelectStmt, got %T", result.Items[0])
+	}
+	if stmt.TargetList == nil || len(stmt.TargetList.Items) != 2 {
+		t.Fatal("expected 2 target list entries")
+	}
+
+	wantNumber := func(t *testing.T, n nodes.Node, want int) {
+		t.Helper()
+		rt, ok := n.(*nodes.ResTarget)
+		if !ok {
+			t.Fatalf("expected *nodes.ResTarget, got %T", n)
+		}
+		pr, ok := rt.Val.(*nodes.ParamRef)
+		if !ok {
+			t.Fatalf("expected *nodes.ParamRef, got %T", rt.Val)
+		}
+		if pr.Number != want {
+			t.Errorf("ParamRef.Number = %d, want %d", pr.Number, want)
+		}
+	}
+
+	wantNumber(t, stmt.TargetList.Items[0], 1)
+	wantNumber(t, stmt.TargetList.Items[1], 2)
+
+	where, ok := stmt.WhereClause.(*nodes.A_Expr)
+	if !ok {
+		t.Fatalf("expected *nodes.A_Expr, got %T", stmt.WhereClause)
+	}
+	pr, ok := where.Rexpr.(*nodes.ParamRef)
+	if !ok {
+		t.Fatalf("expected *nodes.ParamRef, got %T", where.Rexpr)
+	}
+	if pr.Number != 1 {
+		t.Errorf("WHERE clause ParamRef.Number = %d, want 1", pr.Number)
+	}
+}