Update `--accept` behaviour

[naher94]

Another question. Is there a way to skip certain error codes? I notice there is an include (--accept) but didn't see an exclude for codes.

[mre]

Nope, there's just --accept. What should the new parameter be called? Would it take preference over --accept?

[naher94]

Could be called --deny and seems reasonable to follow the same logic of --include "Has preference over all excludes". In this case --accept would take preference, if specified, over --deny

--include
URLs to check (supports regex). Has preference over all excludes

What do we think?

[mre]

Yeah, makes sense to me. I will let this cook for a while to see what other people are thinking. Anyone else who's interested in this, please add a comment.

[thomas-zahner]

Had some thoughts about this. The documentation and help message read the following:

  -a, --accept <ACCEPT>
          A List of accepted status codes for valid links

          The following accept range syntax is supported: [start]..[=]end|code. Some valid
          examples are:

          - 200..=204
          - 200..204
          - ..=204
          - ..204
          - 200

          Use "lychee --accept '200..=204, 429, 500' <inputs>..." to provide a comma-
          separated list of accepted status codes. This example will accept 200, 201,
          202, 203, 204, 429, and 500 as valid status codes.

          [default: 100..=103,200..=299]

At the end we can see the default value for this argument. Also its not possible to specify the argument multiple times. (error: the argument '--accept <ACCEPT>' cannot be used multiple times) Personally, when I read this documentation I would expect to overwrite the default values when specifying --accept. I think --accept should simply list all accepted status codes and overwrite the default values. At the moment the default doesn't seem to be overwritten.

So currently:

lychee --accept 123
Accepts the default values 100..=103,200..=299 plus 123

However it would be simpler if lychee would now only accept the status code 123 and deny any others. The drawback of this would be that we break compatibility (probably quite a few people depend on this flag) and it might be less ergonomic for most use cases. If we think these disadvantages are to great I would agree on adding a --deny flag.

[mre]

You're probably right. It is odd, that --accept does not overwrite the default. I'd be okay with changing that. It follows the principle of least surprise.