./configure --help should print --disable-docs instead of --enable-docs

[dilyanpalauzov]

With rust 1.82 ./configure --help prints:

        --enable-docs  OR  --disable-docs build standard library documentation

This does not indicate if the docs for the standard library will be built if the argument is omitted. If the --help output was

        --disable-docs                  do not build standard library documentation 

this would have suggested, that by default the documentation is built. Cf. https://ab.bapha.be/posts/help-output/)

config.example.toml contains

# Whether to build documentation by default. If false, rustdoc and
# friends will still be compiled but they will not be used to generate any
# documentation.
#
# You can still build documentation when this is disabled by explicitly passing paths,
# e.g. `x doc library`.
#docs = true

For me the last line means, that by default the documentation is build. Indeed, ./configure --disable-docs puts in config.toml: docs = false.

• Change the output of ./configure --help from --enable-docs to --disable-docs to indicate what actions users should take in order to deviate from the default behaviour.

See also #129146.

[clubby789]

The description was copypasted from the previous issue, so I've updated it to be accurate to the current situation. I'm also going to remove the bug label since this is consistent across all enable/disable options, and this is more a discussion of style.

This would require refactoring configure.py to parse the example config first in order to accurately print the defaults.

[onur-ozkan]

The title still doesn't make any sense. Please write the context clearly before opening this or any other issues.

[dilyanpalauzov]

I asked at #129146 to show in ./configure --help for each option, what the default is, if the option is not passed. This was misinterpreted to instead demonstrate, that for each option --disable- can be used, next to --enable-, and moreover I was discouraged to explain in the same ticket what I meant when opening the ticket.

The context is, that I do not want to see, when reading ./configure --help which options I can pass, if passing that particular option does not alter the behaviour anyhow. E.g. ./configure and ./configure --enable-docs do the same, so the help should not spell --enable-docs. Likewise for the other options.

[PatchMixolydic]

Please write the context clearly

The context seems pretty clear to me:

./configure --help should print --disable-docs instead of --enable-docs

because

With rust 1.82 ./configure --help prints:

   --enable-docs  OR  --disable-docs build standard library documentation

This does not indicate if the docs for the standard library will be built if the argument is omitted. If the --help output was

   --disable-docs                  do not build standard library documentation 

this would have suggested, that by default the documentation is built. Cf. https://ab.bapha.be/posts/help-output/)

Shoehorning the entirety of an issue's context into its title has never been a requirement afaict, but a possible alternate title might be "./configure --help should print --disable-* when the default is to --enable-*, and vice-versa". (You could add in a concrete example, explain that this is to elucidate the actual options you have vs. the default configuration, etc., but that would cause the title to balloon in size.)

[onur-ozkan]

The context seems pretty clear to me:

./configure --help should print --disable-docs instead of --enable-docs

$ ./configure --help | rg docs
        --enable-docs  OR  --disable-docs build standard library documentation

We don't just display --enable-docs alone and the configure script doesn't work like "this option is false, so set it to true". If you want to see default values, you should refer to config.example.toml file. As I explained here, it's technically not possible for configure script to do what you are asking. There's also another limitation: we don't have a single default value all the time. The default values depend on other options, and when you run the configure script, those other options haven't been set yet.

[dilyanpalauzov]

We don't just display --enable-docs alone and the configure script doesn't work like "this option is false, so set it to true".

That is the point of this ticket: I asked to change how the configure script works.

There's also another limitation: we don't have a single default value all the time.

This is fine. Then the default value is “check/auto/depends”, and ./configure --help can show it. But in case of some options, like docs, there is a single default value.

Not very relevant, but to be precise, with rust-1.82 ./configure --help does print:

    --enable-docs                  build standard library documentation

as I wrote initially, and it does not emit:

    --enable-docs  OR  --disable-docs build standard library documentation