Crash when --source-file-name used with non-es6 module type - index out of bounds: the len is 0 but the index is 0

[normano64]

Describe the bug

Running the native cli binary on a typescript file that only contain types cause a crash when the --source-file-name flag is used together with the commonjs/umd/amd module type, it doesn't crash with the es6 module type

./swc-linux-x64-gnu compile --source-file-name test.ts --config-file .swcrc test.ts 

thread 'main' panicked at 'index out of bounds: the len is 0 but the index is 0', /usr/local/cargo/registry/src/github.com-1ecc6299db9ec823/sourcemap-6.2.2/src/types.rs:655:9

It seems to work fine for the es6 module type because it still produces a sourcemap when the file is types only while the others are producing empty sourcemaps

Input code

export type Test = {};

Config

{
  "jsc": {
    "parser": {
      "syntax": "typescript"
    }
  },
  "module": {
    "type": "commonjs"
  },
  "sourceMaps": true
}

Playground link

No response

Expected behavior

Compiles without crashing

Actual behavior

Crashes

thread 'main' panicked at 'index out of bounds: the len is 0 but the index is 0', /usr/local/cargo/registry/src/github.com-1ecc6299db9ec823/sourcemap-6.2.2/src/types.rs:655:9

Version

1.3.38

Additional context

No response

[chenyukang]

@kdy1 assign to me?
btw, seems we don't have triagebot such as https://rustc-dev-guide.rust-lang.org/rustbot.html.

[chenyukang]

@realtimetodie
This crash happened at this line:

swc/bindings/swc_cli/src/commands/compile.rs

Line 549 in bb80c65

source_map.set_source(0u32, source_file_name);

Will this function need to be removed? since #1388 is resolved.

The rootcause is when we set non-es6 in config file, the node here is a module whose body is a vec of stmt, all of the stmt's span is dummy.

swc/crates/swc_ecma_codegen/src/lib.rs

Line 95 in bb80c65

pub fn emit_module(&mut self, node: &Module) -> Result {

begin to emit node: Module(Module { span: Span { lo: BytePos(1), hi: BytePos(23), ctxt: #0 }, body: [Stmt(Expr(ExprStmt { span: Span { lo: BytePos(0), hi: BytePos(0), ctxt: #0 }, expr: Lit(Str(Str { span: Span { lo: BytePos(0), hi: BytePos(0), ctxt: #0 }, value: Atom('use strict' type=dynamic), raw: None })) })), Stmt(Expr(ExprStmt { span: Span { lo: BytePos(0), hi: BytePos(0), ctxt: #0 }, expr: Call(CallExpr { span: Span { lo: BytePos(0), hi: BytePos(0), ctxt: #0 }, callee: Expr(Member(MemberExpr { span: Span { lo: BytePos(0), hi: BytePos(0), ctxt: #0 }, obj: Ident(Ident { span: Span { lo: BytePos(0), hi: BytePos(0), ctxt: #0 }, sym: Atom('Object' type=static), optional: false }), prop: Ident(Ident { span: Span { lo: BytePos(0), hi: BytePos(0), ctxt: #0 }, sym: Atom('defineProperty' type=dynamic), optional: false }) })), args: [ExprOrSpread { spread: None, expr: Ident(Ident { span: Span { lo: BytePos(0), hi: BytePos(0), ctxt: #0 }, sym: Atom('exports' type=inline), optional: false }) }, ExprOrSpread { spread: None, expr: Lit(Str(Str { span: Span { lo: BytePos(0), hi: BytePos(0), ctxt: #0 }, value: Atom('__esModule' type=dynamic), raw: None })) }, ExprOrSpread { spread: None, expr: Object(ObjectLit { span: Span { lo: BytePos(0), hi: BytePos(0), ctxt: #0 }, props: [Prop(KeyValue(KeyValueProp { key: Ident(Ident { span: Span { lo: BytePos(0), hi: BytePos(0), ctxt: #0 }, sym: Atom('value' type=inline), optional: false }), value: Lit(Bool(Bool { span: Span { lo: BytePos(0), hi: BytePos(0), ctxt: #0 }, value: true })) }))] }) }], type_args: None }) }))], shebang: None })

so after emitting, the src_map_buf is still empty, which introduced an empty source_map:

swc/crates/swc/src/lib.rs

Line 498 in bb80c65

let mut src_map_buf = vec![];

I think an empty source_map here is expected since the code is only valid for es6?

[kdy1]

I think we may skip #L549 when src_map_buf is empty

[swc-bot]

This closed issue has been automatically locked because it had no new activity for a month. If you are running into a similar issue, please create a new issue with the steps to reproduce. Thank you.