Wrongly source duplication in source map

[lahmatiy]

The minimal code I found to reproduce the problem:

// a.js
import * as t from './b';
export default t;

// b.js
export const x = 1;

Build config:

require('esbuild').build({
    entryPoints: ['a.js'],
    bundle: true,
    sourcemap: true,
    outdir: 'out'
});

esbuild produces a source map:

{
  "version": 3,
  "sources": ["../b.js", "../b.js", "../a.js"],
  "sourcesContent": ["export const x = 1;\n", "export const x = 1;\n", "import * as t from './b';\nexport default t;\n"],
  "mappings": ";;;;;;;;;;AAAA,MAAA;AAAA;AAAA;AAAA;ACAO,MAAM,IAAI;;;ACCjB,MAAO,YAAQ;",
  "names": []
}

The problem is that the source map contains source of b.js twice but should not.

[evanw]

Thanks for reporting this issue. I suspect this is a regression from version 0.7.9 which allows a file to be split into discontiguous pieces (issue #421).