confusing error when running `elm install` on a read-only elm.json

[Zimmi48]

Quick Summary: message triggered by elm install elm/json on a freshly created elm-spa application.

SSCCE

elm-spa init # Accept default values
cd my-elm-spa
elm install elm/json # Accept to move to direct dependencies

Gives the error:

I ran into something that bypassed the normal error reporting process!
extracted whatever information I could from the internal error:

>   /home/theo/my-elm-spa/elm.json: openBinaryFile: permission denied 

• Elm: 0.19.1
• elm-spa: version 5.0.2
• Browser: N/A
• Operating System: NixOS

Additional Details

If this is not reproducible, this might be due to the way I installed Elm and elm-spa using Nix. I would appreciate if someone could tell me whether they can reproduce this issue using the most standard (npm) installation method.

[github-actions[bot]]

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[Zimmi48]

This should have been obvious from the start but I realize this only now: the error comes from the fact that somehow, this elm.json file didn't have any write-permissions. I suppose this is therefore mainly a bug of elm-spa, but I guess I'll still leave the issue open here because the Elm maintainers might still want to fix elm to fail graciously in the case of a read-only elm.json file.