feat(snowflake): parse star ILIKE transform (was mis-parsed as LikeExpr, dropping FROM) (#302)

Author: h3n4l

snowflake/ast/parsenodes.go

@@ -802,15 +802,19 @@ var _ Node = (*SelectStmt)(nil)
 // For expressions: Expr is set, Star is false.
 // For star: Star is true, Expr may be a qualifier (table.*) or nil (bare *).
 //
-// Exclude / Replace / Rename carry the Snowflake star column-transforms that
-// may follow a `*` or `tbl.*`: EXCLUDE drops the named columns; REPLACE
-// substitutes an expression for a column while keeping its name; RENAME
-// aliases columns. Any combination may appear together, in documented order
-// (EXCLUDE, then REPLACE, then RENAME). They are only valid on a star target.
+// Ilike / Exclude / Replace / Rename carry the Snowflake star
+// column-transforms that may follow a `*` or `tbl.*`: ILIKE keeps only the
+// columns whose names match the pattern; EXCLUDE drops the named columns;
+// REPLACE substitutes an expression for a column while keeping its name;
+// RENAME aliases columns. They appear in documented order (ILIKE, then
+// EXCLUDE, then REPLACE, then RENAME) and are only valid on a star target.
+// The docs additionally forbid combining ILIKE with EXCLUDE; the parser
+// over-accepts that combination (semantic validation is a later layer's job).
 type SelectTarget struct {
 	Expr    Node          // expression; nil for bare *
 	Alias   Ident         // AS alias; zero Ident if absent
 	Star    bool          // true for * or qualifier.*
+	Ilike   *Literal      // ILIKE '<pattern>' string literal; nil if absent
 	Exclude []Ident       // EXCLUDE columns; nil if absent
 	Replace []StarReplace // REPLACE expr AS col pairs; nil if absent
 	Rename  []StarRename  // RENAME col AS alias pairs; nil if absent

snowflake/ast/walk_coverage_test.go

@@ -172,6 +172,12 @@ func TestWalkCoverage_SelectClauses(t *testing.T) {
 			sql:  "SELECT * REPLACE (UPPER(ra) AS ssn, rb || rc AS dept) FROM t",
 			cols: []string{"RA", "RB", "RC"},
 		},
+		{
+			name: "SelectTarget.Ilike star-transform pattern",
+			sql:  "SELECT * ILIKE '%id%' REPLACE (UPPER(ra) AS ssn) FROM t",
+			cols: []string{"RA"},
+			lits: []string{"%id%"},
+		},
 		{
 			name: "SelectStmt.With CTE body",
 			sql:  "WITH c AS (SELECT ca FROM t) SELECT * FROM c",

snowflake/ast/walk_generated.go

@@ -238,6 +238,13 @@ func (w *writer) writeSelectTarget(t *ast.SelectTarget) error {
 		} else {
 			w.buf.WriteByte('*')
 		}
+		// ILIKE 'pattern'
+		if t.Ilike != nil {
+			w.buf.WriteString(" ILIKE")
+			if err := w.writeLiteral(t.Ilike); err != nil {
+				return err
+			}
+		}
 		// EXCLUDE (col, ...)
 		if len(t.Exclude) > 0 {
 			w.buf.WriteString(" EXCLUDE (")

snowflake/deparse/deparse_select.go

@@ -134,6 +134,29 @@ func TestDeparse_Select_RenameStarList(t *testing.T) {
 	assertRoundTrip(t, `SELECT * RENAME (a AS b, c AS d) FROM t`)
 }
 
+func TestDeparse_Select_IlikeStar(t *testing.T) {
+	assertRoundTrip(t, `SELECT * ILIKE '%id%' FROM employee_table`)
+}
+
+func TestDeparse_Select_QualifiedStarIlike(t *testing.T) {
+	assertRoundTrip(t, `SELECT t.* ILIKE '%id%' FROM t`)
+}
+
+func TestDeparse_Select_IlikeRenameStar(t *testing.T) {
+	// Corpus official/select/example_12 shape.
+	assertRoundTrip(t, `SELECT * ILIKE '%id%' RENAME (department_id AS department) FROM employee_table`)
+}
+
+func TestDeparse_Select_IlikeReplaceStar(t *testing.T) {
+	// Corpus official/select/example_15 shape.
+	assertRoundTrip(t, `SELECT * ILIKE '%id%' REPLACE ('DEPT-' || department_id AS department_id) FROM employee_table`)
+}
+
+func TestDeparse_Select_IlikeReplaceRenameStar(t *testing.T) {
+	// ILIKE first, then REPLACE, then RENAME — the documented order.
+	assertRoundTrip(t, `SELECT * ILIKE 'col%' REPLACE (UPPER(a) AS a) RENAME (a AS b) FROM t`)
+}
+
 func TestDeparse_Select_ReplaceStar(t *testing.T) {
 	assertRoundTrip(t, `SELECT * REPLACE (UPPER(SSN) AS SSN) FROM T`)
 }

snowflake/deparse/deparse_test.go

@@ -490,7 +490,7 @@ func (p *Parser) selectListTerminator() bool {
 }
 
 // parseSelectTarget parses one item in the SELECT list:
-//   - * [EXCLUDE (col, ...)] [REPLACE (expr AS col, ...)] [RENAME (col AS alias, ...)]
+//   - * [ILIKE 'pattern'] [EXCLUDE (col, ...)] [REPLACE (expr AS col, ...)] [RENAME (col AS alias, ...)]
 //   - expr [AS alias]
 //
 // The expression parser already handles * (StarExpr) and qualifier.*
@@ -508,13 +508,37 @@ func (p *Parser) parseSelectTarget() (*ast.SelectTarget, error) {
 		Loc: ast.Loc{Start: startLoc.Start},
 	}
 
+	// Star ILIKE transform: ILIKE is an infix operator, so for
+	// `* ILIKE '<pattern>'` (and `tbl.* ILIKE ...`) the expression parser has
+	// already bound the star into LikeExpr(StarExpr, pattern) before this
+	// function can see it. A star is not a scalar operand, so in a SELECT
+	// list that shape is unambiguously Snowflake's star ILIKE
+	// column-transform, not a boolean expression — unwrap it here, at the
+	// select-target boundary, so other expression contexts are untouched.
+	// The unwrap keys on the exact documented shape (plain ILIKE with a
+	// string-literal pattern); NOT/ANY/ESCAPE variants and non-literal
+	// patterns are not transforms and stay expressions.
+	if like, ok := expr.(*ast.LikeExpr); ok &&
+		like.Op == ast.LikeOpILike && !like.Not && !like.Any && like.Escape == nil {
+		if _, isStar := like.Expr.(*ast.StarExpr); isStar {
+			if pat, isLit := like.Pattern.(*ast.Literal); isLit && pat.Kind == ast.LitString {
+				expr = like.Expr
+				target.Ilike = pat
+			}
+		}
+	}
+
 	// Check if the expression is a star (* or qualifier.*)
 	if _, ok := expr.(*ast.StarExpr); ok {
 		target.Star = true
 		target.Expr = expr
 
-		// Star column-transforms, in Snowflake's documented order: EXCLUDE,
-		// then REPLACE, then RENAME (any subset may be present).
+		// Star column-transforms, in Snowflake's documented order: ILIKE
+		// (unwrapped above), then EXCLUDE, then REPLACE, then RENAME (any
+		// subset may be present; the docs forbid combining ILIKE with
+		// EXCLUDE, which the parser over-accepts — the combination is
+		// positionally in order and parses soundly).
+		//   ILIKE '<pattern>'
 		//   EXCLUDE <col> | EXCLUDE (<col>, ...)
 		//   REPLACE (<expr> AS <col>, ...)
 		//   RENAME <col> AS <alias> | RENAME (<col> AS <alias>, ...)
@@ -537,15 +561,17 @@ func (p *Parser) parseSelectTarget() (*ast.SelectTarget, error) {
 			}
 		}
 		// A transform keyword still pending here is out of documented order
-		// (e.g. `* RENAME (...) REPLACE (...)`). parseSingle ignores tokens
-		// after a completed statement, so without this check the rest of the
-		// statement — including FROM — would be dropped silently. Fail loudly
-		// instead.
+		// (e.g. `* RENAME (...) REPLACE (...)`, or ILIKE after any other
+		// transform — ILIKE must come first, and in first position it was
+		// already consumed by the expression parse and unwrapped above).
+		// parseSingle ignores tokens after a completed statement, so without
+		// this check the rest of the statement — including FROM — would be
+		// dropped silently. Fail loudly instead.
 		switch p.cur.Type {
-		case kwEXCLUDE, kwREPLACE, kwRENAME:
+		case kwILIKE, kwEXCLUDE, kwREPLACE, kwRENAME:
 			return nil, &ParseError{
 				Loc: p.cur.Loc,
-				Msg: "star column-transforms must appear in EXCLUDE, REPLACE, RENAME order",
+				Msg: "star column-transforms must appear in ILIKE/EXCLUDE, REPLACE, RENAME order",
 			}
 		}
 	} else {