fix #846: remove speculative errors from log

CHANGELOG.md

@@ -51,6 +51,10 @@
 
     Accessing layout-related properties can trigger a layout and accessing storage-related properties can throw an exception if certain privacy settings are enabled. Both of these behaviors are considered side effects.
 
+* Fix a TypeScript parser regression ([#846](https://github.com/evanw/esbuild/issues/846))
+
+    Restrictions on array and object destructuring patterns in the previous release introduced a regression where arrays or objects in TypeScript code could fail to parse if they were wrapped in a double layer of parentheses. This was due to the speculative parsing of arrow function arguments. The regression has been fixed.
+
 ## 0.8.48
 
 * Fix some parsing edge cases ([#835](https://github.com/evanw/esbuild/issues/835))

internal/js_parser/js_parser.go

@@ -2402,6 +2402,10 @@ func (p *parser) convertExprToBindingAndInitializer(expr js_ast.Expr, invalidLog
 	return binding, initializer, invalidLog
 }
 
+// Note: do not write to "p.log" in this function. Any errors due to conversion
+// from expression to binding should be written to "invalidLog" instead. That
+// way we can potentially keep this as an expression if it turns out it's not
+// needed as a binding after all.
 func (p *parser) convertExprToBinding(expr js_ast.Expr, invalidLog []logger.Loc) (js_ast.Binding, []logger.Loc) {
 	switch e := expr.Data.(type) {
 	case *js_ast.EMissing:
@@ -2412,10 +2416,10 @@ func (p *parser) convertExprToBinding(expr js_ast.Expr, invalidLog []logger.Loc)
 
 	case *js_ast.EArray:
 		if e.CommaAfterSpread.Start != 0 {
-			p.log.AddRangeError(&p.source, logger.Range{Loc: e.CommaAfterSpread, Len: 1}, "Unexpected \",\" after rest pattern")
+			invalidLog = append(invalidLog, e.CommaAfterSpread)
 		}
 		if e.IsParenthesized {
-			p.log.AddRangeError(&p.source, p.source.RangeOfOperatorBefore(expr.Loc, "("), "Unexpected \"(\" before array pattern")
+			invalidLog = append(invalidLog, p.source.RangeOfOperatorBefore(expr.Loc, "(").Loc)
 		}
 		p.markSyntaxFeature(compat.Destructuring, p.source.RangeOfOperatorAfter(expr.Loc, "["))
 		items := []js_ast.ArrayBinding{}
@@ -2440,10 +2444,10 @@ func (p *parser) convertExprToBinding(expr js_ast.Expr, invalidLog []logger.Loc)
 
 	case *js_ast.EObject:
 		if e.CommaAfterSpread.Start != 0 {
-			p.log.AddRangeError(&p.source, logger.Range{Loc: e.CommaAfterSpread, Len: 1}, "Unexpected \",\" after rest pattern")
+			invalidLog = append(invalidLog, e.CommaAfterSpread)
 		}
 		if e.IsParenthesized {
-			p.log.AddRangeError(&p.source, p.source.RangeOfOperatorBefore(expr.Loc, "("), "Unexpected \"(\" before object pattern")
+			invalidLog = append(invalidLog, p.source.RangeOfOperatorBefore(expr.Loc, "(").Loc)
 		}
 		p.markSyntaxFeature(compat.Destructuring, p.source.RangeOfOperatorAfter(expr.Loc, "{"))
 		properties := []js_ast.PropertyBinding{}

internal/js_parser/js_parser_test.go

@@ -525,8 +525,8 @@ func TestDecls(t *testing.T) {
 
 	expectParseError(t, "var [...x,] = []", "<stdin>: error: Unexpected \",\" after rest pattern\n")
 	expectParseError(t, "var {...x,} = {}", "<stdin>: error: Unexpected \",\" after rest pattern\n")
-	expectParseError(t, "([...x,] = []) => {}", "<stdin>: error: Unexpected \",\" after rest pattern\n")
-	expectParseError(t, "({...x,} = {}) => {}", "<stdin>: error: Unexpected \",\" after rest pattern\n")
+	expectParseError(t, "([...x,] = []) => {}", "<stdin>: error: Invalid binding pattern\n")
+	expectParseError(t, "({...x,} = {}) => {}", "<stdin>: error: Invalid binding pattern\n")
 
 	expectPrinted(t, "[b, ...c] = d", "[b, ...c] = d;\n")
 	expectPrinted(t, "([b, ...c] = d)", "[b, ...c] = d;\n")
@@ -554,8 +554,8 @@ func TestDecls(t *testing.T) {
 	expectParseError(t, "({}) = {}", "<stdin>: error: Invalid assignment target\n")
 	expectParseError(t, "[([])] = [[]]", "<stdin>: error: Invalid assignment target\n")
 	expectParseError(t, "({x: ({})} = {x: {}})", "<stdin>: error: Invalid assignment target\n")
-	expectParseError(t, "(([]) = []) => {}", "<stdin>: error: Unexpected \"(\" before array pattern\n")
-	expectParseError(t, "(({}) = {}) => {}", "<stdin>: error: Unexpected \"(\" before object pattern\n")
+	expectParseError(t, "(([]) = []) => {}", "<stdin>: error: Invalid binding pattern\n")
+	expectParseError(t, "(({}) = {}) => {}", "<stdin>: error: Invalid binding pattern\n")
 	expectParseError(t, "function f(([]) = []) {}", "<stdin>: error: Expected identifier but found \"(\"\n")
 	expectParseError(t, "function f(({}) = {}) {}", "<stdin>: error: Expected identifier but found \"(\"\n")
 

internal/js_parser/ts_parser_test.go

@@ -1080,6 +1080,15 @@ func TestTSDecl(t *testing.T) {
 	expectParseErrorTS(t, "var a!", "<stdin>: error: Expected \":\" but found end of file\n")
 	expectParseErrorTS(t, "var a! = ", "<stdin>: error: Expected \":\" but found \"=\"\n")
 	expectParseErrorTS(t, "var a!, b", "<stdin>: error: Expected \":\" but found \",\"\n")
+
+	expectPrinted(t, "a ? ({b}) => {} : c", "a ? ({b}) => {\n} : c;\n")
+	expectPrinted(t, "a ? (({b}) => {}) : c", "a ? ({b}) => {\n} : c;\n")
+	expectPrinted(t, "a ? (({b})) : c", "a ? {b} : c;\n")
+	expectParseError(t, "a ? (({b})) => {} : c", "<stdin>: error: Invalid binding pattern\n")
+	expectPrintedTS(t, "a ? ({b}) => {} : c", "a ? ({b}) => {\n} : c;\n")
+	expectPrintedTS(t, "a ? (({b}) => {}) : c", "a ? ({b}) => {\n} : c;\n")
+	expectPrintedTS(t, "a ? (({b})) : c", "a ? {b} : c;\n")
+	expectParseErrorTS(t, "a ? (({b})) => {} : c", "<stdin>: error: Invalid binding pattern\n")
 }
 
 func TestTSDeclare(t *testing.T) {