Unsable to merge 2 very simple source maps

[otakustay]

I have 2 source maps generated from magic-string:

{
  version: 3,
  file: null,
  sources: [ 'test' ],
  sourcesContent: [ 'hello' ],
  names: [],
  mappings: 'AAAA' 
}

{
  version: 3,
  file: null,
  sources: [ 'test' ],
  sourcesContent: [ 'hellosome tail string' ],
  names: [],
  mappings: 'AAAA'
}

The transform steps are hello -> hellosome tail string -> hellosome tail stringsome tail string, each step appends some tail string to original input

When I try to merge them, I get the result:

{
  version: 3,
  sources: [ 'test' ],
  names: [],
  mappings: 'AAAA',
  sourcesContent: [ 'hellosome tail string' ] 
}

This is actually the second source map, and with this map I'm unable to recover the original string hello

I'm wondering whether it is the expected behaiovr?

[otakustay]

I tried to revert the array of line 50 from [oldMapConsumer, newMapConsumer] to [newMapConsumer, oldMapConsumer] and this issue is fixed, the test coverage remains at 100% and all tests pass

If there is no other consideration with the order of this array, I'd like to add some test cases and create a PR for this