stub wasm32-u-u target ?

[pinkforest]

Re: clap-rs/clap#4510

Considering is_terminal is seen as direct migration from atty -

When people are migrating off atty they will get this error under wasm32-u-u if there is callpath to is_terminal:

  --> .cargo/registry/src/github.aaakk.us.kg-1ecc6299db9ec823/errno-0.2.8/src/lib.rs:33:1
   |
33 | mod sys;
   | ^^^^^^^^
   |
   = help: to create the module `sys`, create file ".cargo/registry/src/github.aaakk.us.kg-1ecc6299db9ec823/errno-0.2.8/src/sys.rs" or ".cargo/registry/src/github.aaakk.us.kg-1ecc6299db9ec823/errno-0.2.8/src/sys/mod.rs"

error[E0425]: cannot find function `errno` in module `sys`
   --> .cargo/registry/src/github.aaakk.us.kg-1ecc6299db9ec823/errno-0.2.8/src/lib.rs:101:10
    |
101 |     sys::errno()
    |          ^^^^^ not found in `sys`

error[E0425]: cannot find function `set_errno` in module `sys`
   --> .cargo/registry/src/github.aaakk.us.kg-1ecc6299db9ec823/errno-0.2.8/src/lib.rs:106:10
    |
106 |     sys::set_errno(err)
    |          ^^^^^^^^^ not found in `sys`

Would it be feasible to stub out wasm32-u-u that it still builds and provides false to is_terminal ?

Or at least if the dependency is there it does not try to build stuff in wasm32-u-u that will fail to compile ?

Considering the below -

Even if one stamps out the calls to is_terminal then io-lifetimes doesn't build at all if it's present in the dependencies

Sometimes the dependencies come via default features as in case of clap which made it pretty complicated to remove -

Yeah I know wasm32-u-u doesn't have terminal but would it be feasible to provide stubs for it to ease migration ?

Or at least cfg gate some of it out @ target_family = "wasm", target_os = "unknown" ?

Cheers

[sunfishcode]

Yes, I think a stub that returns false makes sense. I'll add that.

[epage]

Also for wasm32-unknown-unknown

error[E0432]: unresolved imports `portability::AsFilelike`, `portability::AsSocketlike`, `portability::BorrowedFilelike`, `portability::BorrowedSocketlike`, `portability::FromFilelike`, `portability::FromSocketlike`, `portability::IntoFilelike`, `portability::IntoSocketlike`, `portability::OwnedFilelike`, `portability::OwnedSocketlike`
   --> /home/runner/.cargo/registry/src/github.aaakk.us.kg-1ecc6299db9ec823/io-lifetimes-1.0.1/src/lib.rs:157:5
    |
157 |     AsFilelike, AsSocketlike, BorrowedFilelike, BorrowedSocketlike, FromFilelike, FromSocketlike,
    |     ^^^^^^^^^^  ^^^^^^^^^^^^  ^^^^^^^^^^^^^^^^  ^^^^^^^^^^^^^^^^^^  ^^^^^^^^^^^^  ^^^^^^^^^^^^^^ no `FromSocketlike` in `portability`
    |     |           |             |                 |                   |
    |     |           |             |                 |                   no `FromFilelike` in `portability`
    |     |           |             |                 no `BorrowedSocketlike` in `portability`
    |     |           |             no `BorrowedFilelike` in `portability`
    |     |           no `AsSocketlike` in `portability`
    |     no `AsFilelike` in `portability`
158 |     IntoFilelike, IntoSocketlike, OwnedFilelike, OwnedSocketlike,
    |     ^^^^^^^^^^^^  ^^^^^^^^^^^^^^  ^^^^^^^^^^^^^  ^^^^^^^^^^^^^^^ no `OwnedSocketlike` in `portability`
    |     |             |               |
    |     |             |               no `OwnedFilelike` in `portability`
    |     |             no `IntoSocketlike` in `portability`
    |     no `IntoFilelike` in `portability`

[epage]

Also, some calls are already stubbed. The issue will be making the dependencies platform specific.

@sunfishcode would you like me to take a stab at this?

[sunfishcode]

I've just release io-lifetimes 1.0.3 which avoids defining things that don't work on wasm32-unknown-unknown, which fixes the immediate compilation errors.

Looking at this more closely though, this makes it impossible to support is-terminal's current API on wasm32-unknoown-unknown because is-terminal expects a handle argument, and there are no handle types defined on wasm32-unknown-unknown.

I'm considering adding additional functions to is-terminal, such as fn stdout_is_terminal() -> bool, and similar for stdin/stderr, which avoid taking a handle. They'd work on all platforms, and on platforms that have no handle types, they'd be the only thing that works.

[sunfishcode]

Ah, I was mistaken above. We can implement is-terminal for Stdout and similar types; I've now submitted #10 to implement this.

[pinkforest]

Cool. It all builds now 👍 thanks!