Critical assertion error generating source maps

[GianlucaGuarini]

I am working since days on a Riot.js compiler bug, this issue is driving me mad. I have noticed that the problem is coming from the recast.print method when it tries to generate the sourcemaps.

I was able to reproduce the issue with a few lines of code here

That's the code to reproduce it in case you want to try to copy and paste it directly in your editor:

const recast = require('recast')
const types = recast.types
const builders = recast.types.builders
const scope = builders.identifier('scope')

const expression = `(

                                                 {
    complete: onComplete,
    translateX: 100
  })`

const ast = recast.parse(expression, {
  sourceFileName: 'test.js',

})

// replace the scope of the identifiers found
types.visit(ast, {
  visitIdentifier(path) {
    path.replace(builders.memberExpression(
      scope,
      path.node,
      false
    ))

    return false
  }
})

// crate a function 
const result = builders.functionExpression(
  null,
  [scope],
  builders.blockStatement([builders.returnStatement(
    ast.program.body[0].expression
  )])
)

// generate the output
const output = recast.print(result, {
  sourceMapName: `source.map`
})

return output

Any hint or help solving this issue is really appreciated as long as the sourcemap output will be correct :)

Thank you

[eventualbuddha]

Replacing an identifier with a member expression is not always safe. You’ll be replacing the keys in your object with e.g. scope.translateX, which is not a valid key.

[GianlucaGuarini]

@eventualbuddha thank you for your feedback. The @riotjs/compiler is much more complex than this demo. The code above is just needed to show the issue in recast that seems to be clearly related to the breaking spaces since the following demo works as expected: https://runkit.com/gianlucaguarini/5fe44ae13e9cdb001a56fc21

[eventualbuddha]

Ah, you're right. I don't know what's causing the issue you're seeing, but it does appear to be a bug. Thanks for clarifying.

[GianlucaGuarini]

@benjamn do you accept PRs? I might be interested in solving this issue with a patch

[eventualbuddha]

Yep, though it may not happen quickly.

[GianlucaGuarini]

@eventualbuddha I have tried to keep the patch simple https://github.com/benjamn/recast/pull/989 but your help on it is highly appreciated.

[GianlucaGuarini]

I am not able to reproduce this issue with the newest recast version. I am going to close this issue and my PR. Thank you anyway :)