Unexpected warning: `The option '--compat' is not registered with the 'new' command. Run 'ember new --help' for a list of supported options.`

[johanrd]

Steps to reproduce

Follow readme for --no-compat option: https://github.com/ember-cli/ember-app-blueprint?tab=readme-ov-file#--no-compat

pnpm dlx ember-cli@latest new my-app-name \
  --blueprint @ember/app-blueprint@alpha \
  --pnpm \
  --no-compat

Unexpected warning:

The option '--compat' is not registered with the 'new' command. Run `ember new --help` for a list of supported options.
installing app-blueprint

Environment:

ember v                             
ember-cli: 6.9.1
node: 24.11.0
os: darwin arm64

[void-mAlex]

this is correct following
#187
see
emberjs/rfcs#1161
for the RFC to add the "compat" flag formally

[mansona]

This was extensively discussed at the tooling team meeting https://github.com/emberjs/core-notes/blob/master/st-embroider/2024/2026-01-13.md#consider-reverting---minimal-and---no-compat-httpsgithubcomember-cliember-app-blueprintpull49issuecomment-3740430054-mansona

Essentially --no-compat was added prematurely. Even apart from that it's a very experimental mode that 99.9% of people should not be generating their apps with (for a lot of reasons) and we really shouldn't be telling people to try it out anywhere 🙈

[johanrd]

thanks, no worries! I really appreciate the efforts for --no-compat, it was just unexpected from the steps in readme.

[mansona]

ah ok I haven't merged the beta forward yet 🙈 sorry about that

[NullVoxPopuli]

You can still use

pnpm dlx ember-cli@latest new my-app-name \
  --blueprint @ember/app-blueprint@6.11.0-alpha.2 \
  --pnpm \
  --no-compat

If you want

[mansona]

@NullVoxPopuli can we please stop encouraging people to do things like this 🙈 it's probably not even going to work on the last 6.11 alpha and it won't work on the 6.11 beta so that exact number is very much a magic string. And none of the eventual fixes that will need to make it into ember or the blueprint will be included in that version

[NullVoxPopuli]

We have a disagreement on usage, importance, and role of compat is all.

I'll stop it with this blueprint tho

[mansona]

we don't have a disagreement on usage of compat, we only have a disagreement on timing. I 100% agree with you that we should eventually no longer ship compat with the default blueprint and we should probably do that with an option before it becomes the default, but we can't skip any steps. We know what the next steps are and that is where we should focus our effort and try to minmise confusing communication around this topic 👍

[NullVoxPopuli]

That next step is compatModules supporting strict resolver.

[johanrd]

Thanks. To be fair, I really did this just to experiment, so no harm done for me at all (I did consider it alpha testing), but I also understand it can be perceived as too much noise to answer such an issue as well.

<3