cmd: fix regression in auto-detect of Caddyfile

[mohammed90]

Regression caused by #6356
Reported here:

• https://caddy.community/t/error-in-logs-with-updating-ari-after-upgrading-to-caddy-v2-8-1/24320/12
• cmd: fix auto-detetction of .caddyfile extension #6356 (comment)
• fixes Error: ambiguous config file format; please specify adapter (use --adapter) since 2.8.2 #6363

[francislavoie]

Can we add more test coverage for this?

[mholt]

Thanks for the quick patch. Some mostly unimportant thoughts...

[mholt]

This case is still confusing to me 😅 and I almost wonder if it should be an error.

[mholt]

We can duke it out later, but might be worth discussing at some point.

[mohammed90]

I'm using an error return as a signal of ambiguity. We consider .json a known extension, so it's not ambiguous. The determination is: .json is not ambiguous and isn't a Caddyfile.

[francislavoie]

I use files like Caddyfile.test2 kinda thing, it's not uncommon to have like Caddyfile.dev and Caddyfile.prod. I'm not sure I understand how those will behave from looking at the code (just woke up and still away from home 😅)

[mohammed90]

If you pass the --adpater, it will go through as Caddyfile. If this is common, I'd rather we strip the whole .caddyfile detection out.

[francislavoie]

I think it is common, and historically it has gone with the "starts with Caddyfile" rule. I think we only want to say it's ambiguous if there is a loaded adapter that matches the extension, not otherwise. I think it's fine if Caddyfile.yaml works if the yaml adapter isn't loaded. I realize that it's probably hard to test for though since we don't have any in Caddy itself. Maybe for testing, can make a dummy adapter?

[mohammed90]

Then I think we should accept that users make silly mistakes such as passing --config Caddyfile.yaml without --adapter, or will do caddy run without specifying the --adapter which will cause the yaml file to be read as Caddyfile. It'll just fail silently (or loudly 🤷🏼‍♂️ ).

[mholt]

Thank you!

I will merge this and tag a new release now.