breaks compile by removing non-redundant imports

[robx]

I have imports

import Svg
import Svg.Attributes as Svg
import Svg.Attributes

and access most attributes as Svg.<attribute>. But both Svg and Svg.Attributes define style, so I need the third import to be able to access Svg.Attributes.Style explicitly. elm-format however removes that import statement, converting compiling elm code to non-compiling elm-code.

(Yes, that import situation is a bit messy; it seems that the real Svg.style isn't accessible at all anymore.)

[newmana]

This took at least a day to debug - as we were accidentally reformatting code in elm-stuff and getting the terrible error message:

The elm-package.json constraints of ‘abadi199/elm-input-extra’ are probably
letting too much stuff through. Definitely open an issue on the relevant github
repo to get this fixed and save other people from this pain.

In the meantime, take a look through the direct dependencies of the broken
package and see if any of them have had releases recently. If you find the new
thing that is causing problems, you can artificially constrain things by adding
some extra constraints to your elm-package.json as a stopgap measure.

Would work on some people's computers and not on others depending on how they'd setup their elm-format (version, directory).

Would suggest an invariant for elm-format is - code compiles -> reformat -> code compiles.

[avh4]

@newmana for reference, can you give the imports your project had that were being collapsed?

[newmana]

See this pull request (you might have missed that linked above):
abadi199/elm-input-extra#11

Run 0.7.0-exp on:
https://github.com/abadi199/elm-input-extra/blob/1a4116812b0979c63bfbae9e18d960c80bc81bfb/src/Input/Number.elm

Specifically on that file:
import Html.Attributes exposing (style, type_)
import Html.Attributes as Attributes exposing (value)

Becomes:
import Html.Attributes as Attributes exposing (value, style, type_)

Which means Html.Attributes.min/max no longer works.

For example: https://github.com/abadi199/elm-input-extra/blob/1a4116812b0979c63bfbae9e18d960c80bc81bfb/src/Input/Number.elm#L157

[aforemny]

(comment deleted, I instead commented on #379)