SourceMapBuilder behaves wrongly if I add same source multiple times

[kdy1]

Environment

Context: swc-project/swc#8789

What version are you running: latest

Steps to Reproduce

1. What
2. you
3. did.

I'm trying to accept https://github.com/noyobo/swc-issues/blob/676db973ad2d5085adbb9e46188ae5c8a2a2a935/a.js.map as inputSourceMap for SWC.

But

        let mut builder = SourceMapBuilder::new(None);

        let mut src_id = 0u32;

        if let Some(orig) = orig {
            dbg!(orig.sources().count());
            for src in orig.sources() {
                let id = builder.add_source(src);
                if src_id != 0 && src_id >= id {
                    panic!("source id is not unique: {}", id);
                }
                dbg!(id);
                if id == 192 {
                    dbg!(src);
                }

                src_id = id;

                builder.set_source_contents(id, orig.get_source_contents(id));
            }
        }

this code fails with

[crates/swc_common/src/source_map.rs:1231:21] src = "/Users/noyobo/home/gitlab/tuya-public/illuminate-base-mp/dist/../dist/src/components.ts"
[crates/swc_common/src/source_map.rs:1229:17] id = 193
[crates/swc_common/src/source_map.rs:1229:17] id = 194
[crates/swc_common/src/source_map.rs:1229:17] id = 195
[crates/swc_common/src/source_map.rs:1229:17] id = 196
[crates/swc_common/src/source_map.rs:1229:17] id = 197
[crates/swc_common/src/source_map.rs:1229:17] id = 198
[crates/swc_common/src/source_map.rs:1229:17] id = 199
[crates/swc_common/src/source_map.rs:1229:17] id = 200
[crates/swc_common/src/source_map.rs:1229:17] id = 201
thread 'fixture_tests__fixture__issues_8xxx__8789__input' panicked at /Users/kdy1/projects/s/issues/crates/swc_common/src/source_map.rs:1227:21:
source id is not unique: 192

because SourceMapBuilder uses HashMap for sources internally.

Expected Result

SourceMapBuilder.add_sources should return a different value for the same input, if it's call multiple times.

Actual Result

192 is returned multiple times, even though the original source map uses both 202 and 192 for source_id and the number of total sources is 300. So the tokens uses 0299, but source_id is 0298.

[loewenheim]

If I understand correctly, you are reconstructing an existing sourcemap with SourcemapBuilder, right? Is there a reason you can't parse the existing sourcemap?

[kdy1]

I need to create a new source map based on the provided source map. Is there a way to apply remapping of source map without adding them to the SourceMapBuilder for the final sourcemap?

[loewenheim]

What do you mean by remapping? Would it be correct to say that you want to take an existing sourcemap and edit it somehow?

[kdy1]

I found adjust_mapping. Sorry for the noise, I'll try it first.

[loewenheim]

Not at all, please let me know if I can answer any more questions.

[kdy1]

I tried using adjust_mapping with swc-project/swc#9052 but it has a bug so I reverted it with swc-project/swc#9437

[kdy1]

Oh, I should reversing the source map order. I'll report back.

[loewenheim]

Closing this for now, please let us know if we can assist you further.