build fails for wasm32-wasi target

[wucke13]

Rust Version

rustc 1.42.0 (b8cedc004 2020-03-09)

Code

fn main()->{}

Steps to reproduce the issue

1. Run cargo run --target wasm32-wasi

Affected Version of clap*

master

Actual Behavior Summary

The compilation does not finish due to 31 errors, mostly:

• error[E0599]: no function or associated item named from_bytes found for struct std::ffi::OsStr in the current scope
• error[E0599]: no method named as_bytes found for reference &std::ffi::OsStr in the current scope

Expected Behavior Summary

The compilation does finish with 0 errors

Additional context

I really like the idea of having universal bytecode, and I really like powerful CLI tools. I would love to use clap for the wasm32-wasi target!

[Dylan-DPC-zz]

Yeah i don't think we support or have focused supporting this target. Will need to investigate a way out. If possible can you share all the errors? Thanks

[wucke13]

Sure, it is really just those too errors.

error[E0599]: no method named `as_bytes` found for reference `&std::ffi::OsStr` in the current scope
   --> /home/wucke13/.cargo/git/checkouts/clap-78dbe9b58f9073fe/4b5d772/src/parse/parser.rs:440:49
    |
440 |                 let key_bytes = OsStr::new(key).as_bytes();
    |                                                 ^^^^^^^^ method not found in `&std::ffi::OsStr`
    |
    = help: items from traits can only be used if the trait is in scope
    = note: the following trait is implemented but not in scope; perhaps add a `use` for it:
            `use std::os::wasi::ffi::OsStrExt;`

error[E0599]: no method named `as_bytes` found for reference `&std::ffi::OsStr` in the current scope
   --> /home/wucke13/.cargo/git/checkouts/clap-78dbe9b58f9073fe/4b5d772/src/parse/parser.rs:442:40
    |
442 |                 if key_bytes == arg_os.as_bytes() {
    |                                        ^^^^^^^^ method not found in `&std::ffi::OsStr`
    |
    = help: items from traits can only be used if the trait is in scope
    = note: the following trait is implemented but not in scope; perhaps add a `use` for it:
            `use std::os::wasi::ffi::OsStrExt;`

error[E0599]: no function or associated item named `from_bytes` found for struct `std::ffi::OsStr` in the current scope
    --> /home/wucke13/.cargo/git/checkouts/clap-78dbe9b58f9073fe/4b5d772/src/build/arg/mod.rs:2305:41
     |
2305 |         self.default_values_os(&[OsStr::from_bytes(val.as_bytes())])
     |                                         ^^^^^^^^^^ function or associated item not found in `std::ffi::OsStr`
     |
     = help: items from traits can only be used if the trait is in scope
     = note: the following trait is implemented but not in scope; perhaps add a `use` for it:
             `use std::os::wasi::ffi::OsStrExt;`

error[E0599]: no function or associated item named `from_bytes` found for struct `std::ffi::OsStr` in the current scope
    --> /home/wucke13/.cargo/git/checkouts/clap-78dbe9b58f9073fe/4b5d772/src/build/arg/mod.rs:2321:31
     |
2321 |             .map(|val| OsStr::from_bytes(val.as_bytes()))
     |                               ^^^^^^^^^^ function or associated item not found in `std::ffi::OsStr`
     |
     = help: items from traits can only be used if the trait is in scope
     = note: the following trait is implemented but not in scope; perhaps add a `use` for it:
             `use std::os::wasi::ffi::OsStrExt;`

error[E0599]: no function or associated item named `from_bytes` found for struct `std::ffi::OsStr` in the current scope
    --> /home/wucke13/.cargo/git/checkouts/clap-78dbe9b58f9073fe/4b5d772/src/build/arg/mod.rs:2440:47
     |
2440 |             val.map(str::as_bytes).map(OsStr::from_bytes),
     |                                               ^^^^^^^^^^ function or associated item not found in `std::ffi::OsStr`
     |
     = help: items from traits can only be used if the trait is in scope
     = note: the following trait is implemented but not in scope; perhaps add a `use` for it:
             `use std::os::wasi::ffi::OsStrExt;`

error[E0599]: no function or associated item named `from_bytes` found for struct `std::ffi::OsStr` in the current scope
    --> /home/wucke13/.cargo/git/checkouts/clap-78dbe9b58f9073fe/4b5d772/src/build/arg/mod.rs:2441:20
     |
2441 |             OsStr::from_bytes(default.as_bytes()),
     |                    ^^^^^^^^^^ function or associated item not found in `std::ffi::OsStr`
     |
     = help: items from traits can only be used if the trait is in scope
     = note: the following trait is implemented but not in scope; perhaps add a `use` for it:
             `use std::os::wasi::ffi::OsStrExt;`

error[E0599]: no function or associated item named `from_bytes` found for struct `std::ffi::OsStr` in the current scope
    --> /home/wucke13/.cargo/git/checkouts/clap-78dbe9b58f9073fe/4b5d772/src/build/arg/mod.rs:2559:51
     |
2559 |                 val.map(str::as_bytes).map(OsStr::from_bytes),
     |                                                   ^^^^^^^^^^ function or associated item not found in `std::ffi::OsStr`
     |
     = help: items from traits can only be used if the trait is in scope
     = note: the following trait is implemented but not in scope; perhaps add a `use` for it:
             `use std::os::wasi::ffi::OsStrExt;`

error[E0599]: no function or associated item named `from_bytes` found for struct `std::ffi::OsStr` in the current scope
    --> /home/wucke13/.cargo/git/checkouts/clap-78dbe9b58f9073fe/4b5d772/src/build/arg/mod.rs:2560:24
     |
2560 |                 OsStr::from_bytes(default.as_bytes()),
     |                        ^^^^^^^^^^ function or associated item not found in `std::ffi::OsStr`
     |
     = help: items from traits can only be used if the trait is in scope
     = note: the following trait is implemented but not in scope; perhaps add a `use` for it:
             `use std::os::wasi::ffi::OsStrExt;`

error[E0599]: no method named `as_bytes` found for reference `&std::ffi::OsStr` in the current scope
   --> /home/wucke13/.cargo/git/checkouts/clap-78dbe9b58f9073fe/4b5d772/src/parse/parser.rs:796:29
    |
796 |             let n_bytes = n.as_bytes();
    |                             ^^^^^^^^ method not found in `&std::ffi::OsStr`
    |
    = help: items from traits can only be used if the trait is in scope
    = note: the following trait is implemented but not in scope; perhaps add a `use` for it:
            `use std::os::wasi::ffi::OsStrExt;`

error[E0599]: no method named `as_bytes` found for reference `&std::ffi::OsStr` in the current scope
   --> /home/wucke13/.cargo/git/checkouts/clap-78dbe9b58f9073fe/4b5d772/src/parse/parser.rs:797:41
    |
797 |             let h_bytes = OsStr::new(h).as_bytes();
    |                                         ^^^^^^^^ method not found in `&std::ffi::OsStr`
    |
    = help: items from traits can only be used if the trait is in scope
    = note: the following trait is implemented but not in scope; perhaps add a `use` for it:
            `use std::os::wasi::ffi::OsStrExt;`

error[E0599]: no method named `as_bytes` found for reference `&std::ffi::OsStr` in the current scope
  --> /home/wucke13/.cargo/git/checkouts/clap-78dbe9b58f9073fe/4b5d772/src/util/osstringext.rs:37:14
   |
37 |         self.as_bytes().starts_with(s)
   |              ^^^^^^^^ method not found in `&std::ffi::OsStr`
   |
   = help: items from traits can only be used if the trait is in scope
   = note: the following trait is implemented but not in scope; perhaps add a `use` for it:
           `use std::os::wasi::ffi::OsStrExt;`

error[E0599]: no method named `as_bytes` found for reference `&std::ffi::OsStr` in the current scope
  --> /home/wucke13/.cargo/git/checkouts/clap-78dbe9b58f9073fe/4b5d772/src/util/osstringext.rs:41:23
   |
41 |         for b in self.as_bytes() {
   |                       ^^^^^^^^ method not found in `&std::ffi::OsStr`
   |
   = help: items from traits can only be used if the trait is in scope
   = note: the following trait is implemented but not in scope; perhaps add a `use` for it:
           `use std::os::wasi::ffi::OsStrExt;`

error[E0599]: no method named `as_bytes` found for reference `&std::ffi::OsStr` in the current scope
  --> /home/wucke13/.cargo/git/checkouts/clap-78dbe9b58f9073fe/4b5d772/src/util/osstringext.rs:50:28
   |
50 |         for (i, b) in self.as_bytes().iter().enumerate() {
   |                            ^^^^^^^^ method not found in `&std::ffi::OsStr`
   |
   = help: items from traits can only be used if the trait is in scope
   = note: the following trait is implemented but not in scope; perhaps add a `use` for it:
           `use std::os::wasi::ffi::OsStrExt;`

error[E0599]: no function or associated item named `from_bytes` found for struct `std::ffi::OsStr` in the current scope
  --> /home/wucke13/.cargo/git/checkouts/clap-78dbe9b58f9073fe/4b5d772/src/util/osstringext.rs:53:28
   |
53 |                     OsStr::from_bytes(&self.as_bytes()[..i]),
   |                            ^^^^^^^^^^ function or associated item not found in `std::ffi::OsStr`
   |
   = help: items from traits can only be used if the trait is in scope
   = note: the following trait is implemented but not in scope; perhaps add a `use` for it:
           `use std::os::wasi::ffi::OsStrExt;`

error[E0599]: no method named `as_bytes` found for reference `&std::ffi::OsStr` in the current scope
  --> /home/wucke13/.cargo/git/checkouts/clap-78dbe9b58f9073fe/4b5d772/src/util/osstringext.rs:53:45
   |
53 |                     OsStr::from_bytes(&self.as_bytes()[..i]),
   |                                             ^^^^^^^^ method not found in `&std::ffi::OsStr`
   |
   = help: items from traits can only be used if the trait is in scope
   = note: the following trait is implemented but not in scope; perhaps add a `use` for it:
           `use std::os::wasi::ffi::OsStrExt;`

error[E0599]: no function or associated item named `from_bytes` found for struct `std::ffi::OsStr` in the current scope
  --> /home/wucke13/.cargo/git/checkouts/clap-78dbe9b58f9073fe/4b5d772/src/util/osstringext.rs:54:28
   |
54 |                     OsStr::from_bytes(&self.as_bytes()[i + 1..]),
   |                            ^^^^^^^^^^ function or associated item not found in `std::ffi::OsStr`
   |
   = help: items from traits can only be used if the trait is in scope
   = note: the following trait is implemented but not in scope; perhaps add a `use` for it:
           `use std::os::wasi::ffi::OsStrExt;`

error[E0599]: no method named `as_bytes` found for reference `&std::ffi::OsStr` in the current scope
  --> /home/wucke13/.cargo/git/checkouts/clap-78dbe9b58f9073fe/4b5d772/src/util/osstringext.rs:54:45
   |
54 |                     OsStr::from_bytes(&self.as_bytes()[i + 1..]),
   |                                             ^^^^^^^^ method not found in `&std::ffi::OsStr`
   |
   = help: items from traits can only be used if the trait is in scope
   = note: the following trait is implemented but not in scope; perhaps add a `use` for it:
           `use std::os::wasi::ffi::OsStrExt;`

error[E0599]: no function or associated item named `from_bytes` found for struct `std::ffi::OsStr` in the current scope
  --> /home/wucke13/.cargo/git/checkouts/clap-78dbe9b58f9073fe/4b5d772/src/util/osstringext.rs:60:20
   |
60 |             OsStr::from_bytes(&self.as_bytes()[self.len()..self.len()]),
   |                    ^^^^^^^^^^ function or associated item not found in `std::ffi::OsStr`
   |
   = help: items from traits can only be used if the trait is in scope
   = note: the following trait is implemented but not in scope; perhaps add a `use` for it:
           `use std::os::wasi::ffi::OsStrExt;`

error[E0599]: no method named `as_bytes` found for reference `&std::ffi::OsStr` in the current scope
  --> /home/wucke13/.cargo/git/checkouts/clap-78dbe9b58f9073fe/4b5d772/src/util/osstringext.rs:60:37
   |
60 |             OsStr::from_bytes(&self.as_bytes()[self.len()..self.len()]),
   |                                     ^^^^^^^^ method not found in `&std::ffi::OsStr`
   |
   = help: items from traits can only be used if the trait is in scope
   = note: the following trait is implemented but not in scope; perhaps add a `use` for it:
           `use std::os::wasi::ffi::OsStrExt;`

error[E0599]: no method named `as_bytes` found for reference `&std::ffi::OsStr` in the current scope
  --> /home/wucke13/.cargo/git/checkouts/clap-78dbe9b58f9073fe/4b5d772/src/util/osstringext.rs:66:28
   |
66 |         for (i, b) in self.as_bytes().iter().enumerate() {
   |                            ^^^^^^^^ method not found in `&std::ffi::OsStr`
   |
   = help: items from traits can only be used if the trait is in scope
   = note: the following trait is implemented but not in scope; perhaps add a `use` for it:
           `use std::os::wasi::ffi::OsStrExt;`

error[E0599]: no function or associated item named `from_bytes` found for struct `std::ffi::OsStr` in the current scope
  --> /home/wucke13/.cargo/git/checkouts/clap-78dbe9b58f9073fe/4b5d772/src/util/osstringext.rs:68:31
   |
68 |                 return OsStr::from_bytes(&self.as_bytes()[i..]);
   |                               ^^^^^^^^^^ function or associated item not found in `std::ffi::OsStr`
   |
   = help: items from traits can only be used if the trait is in scope
   = note: the following trait is implemented but not in scope; perhaps add a `use` for it:
           `use std::os::wasi::ffi::OsStrExt;`

error[E0599]: no method named `as_bytes` found for reference `&std::ffi::OsStr` in the current scope
  --> /home/wucke13/.cargo/git/checkouts/clap-78dbe9b58f9073fe/4b5d772/src/util/osstringext.rs:68:48
   |
68 |                 return OsStr::from_bytes(&self.as_bytes()[i..]);
   |                                                ^^^^^^^^ method not found in `&std::ffi::OsStr`
   |
   = help: items from traits can only be used if the trait is in scope
   = note: the following trait is implemented but not in scope; perhaps add a `use` for it:
           `use std::os::wasi::ffi::OsStrExt;`

error[E0599]: no function or associated item named `from_bytes` found for struct `std::ffi::OsStr` in the current scope
  --> /home/wucke13/.cargo/git/checkouts/clap-78dbe9b58f9073fe/4b5d772/src/util/osstringext.rs:74:27
   |
74 |             return OsStr::from_bytes(&self.as_bytes()[self.len()..]);
   |                           ^^^^^^^^^^ function or associated item not found in `std::ffi::OsStr`
   |
   = help: items from traits can only be used if the trait is in scope
   = note: the following trait is implemented but not in scope; perhaps add a `use` for it:
           `use std::os::wasi::ffi::OsStrExt;`

error[E0599]: no method named `as_bytes` found for reference `&std::ffi::OsStr` in the current scope
  --> /home/wucke13/.cargo/git/checkouts/clap-78dbe9b58f9073fe/4b5d772/src/util/osstringext.rs:74:44
   |
74 |             return OsStr::from_bytes(&self.as_bytes()[self.len()..]);
   |                                            ^^^^^^^^ method not found in `&std::ffi::OsStr`
   |
   = help: items from traits can only be used if the trait is in scope
   = note: the following trait is implemented but not in scope; perhaps add a `use` for it:
           `use std::os::wasi::ffi::OsStrExt;`

error[E0599]: no function or associated item named `from_bytes` found for struct `std::ffi::OsStr` in the current scope
  --> /home/wucke13/.cargo/git/checkouts/clap-78dbe9b58f9073fe/4b5d772/src/util/osstringext.rs:81:20
   |
81 |             OsStr::from_bytes(&self.as_bytes()[..i]),
   |                    ^^^^^^^^^^ function or associated item not found in `std::ffi::OsStr`
   |
   = help: items from traits can only be used if the trait is in scope
   = note: the following trait is implemented but not in scope; perhaps add a `use` for it:
           `use std::os::wasi::ffi::OsStrExt;`

error[E0599]: no method named `as_bytes` found for reference `&std::ffi::OsStr` in the current scope
  --> /home/wucke13/.cargo/git/checkouts/clap-78dbe9b58f9073fe/4b5d772/src/util/osstringext.rs:81:37
   |
81 |             OsStr::from_bytes(&self.as_bytes()[..i]),
   |                                     ^^^^^^^^ method not found in `&std::ffi::OsStr`
   |
   = help: items from traits can only be used if the trait is in scope
   = note: the following trait is implemented but not in scope; perhaps add a `use` for it:
           `use std::os::wasi::ffi::OsStrExt;`

error[E0599]: no function or associated item named `from_bytes` found for struct `std::ffi::OsStr` in the current scope
  --> /home/wucke13/.cargo/git/checkouts/clap-78dbe9b58f9073fe/4b5d772/src/util/osstringext.rs:82:20
   |
82 |             OsStr::from_bytes(&self.as_bytes()[i..]),
   |                    ^^^^^^^^^^ function or associated item not found in `std::ffi::OsStr`
   |
   = help: items from traits can only be used if the trait is in scope
   = note: the following trait is implemented but not in scope; perhaps add a `use` for it:
           `use std::os::wasi::ffi::OsStrExt;`

error[E0599]: no method named `as_bytes` found for reference `&std::ffi::OsStr` in the current scope
  --> /home/wucke13/.cargo/git/checkouts/clap-78dbe9b58f9073fe/4b5d772/src/util/osstringext.rs:82:37
   |
82 |             OsStr::from_bytes(&self.as_bytes()[i..]),
   |                                     ^^^^^^^^ method not found in `&std::ffi::OsStr`
   |
   = help: items from traits can only be used if the trait is in scope
   = note: the following trait is implemented but not in scope; perhaps add a `use` for it:
           `use std::os::wasi::ffi::OsStrExt;`

error[E0599]: no method named `as_bytes` found for reference `&std::ffi::OsStr` in the current scope
  --> /home/wucke13/.cargo/git/checkouts/clap-78dbe9b58f9073fe/4b5d772/src/util/osstringext.rs:89:23
   |
89 |             val: self.as_bytes(),
   |                       ^^^^^^^^ method not found in `&std::ffi::OsStr`
   |
   = help: items from traits can only be used if the trait is in scope
   = note: the following trait is implemented but not in scope; perhaps add a `use` for it:
           `use std::os::wasi::ffi::OsStrExt;`

error[E0599]: no function or associated item named `from_bytes` found for struct `std::ffi::OsStr` in the current scope
   --> /home/wucke13/.cargo/git/checkouts/clap-78dbe9b58f9073fe/4b5d772/src/util/osstringext.rs:115:36
    |
115 |                 return Some(OsStr::from_bytes(&self.val[start..self.pos - 1]));
    |                                    ^^^^^^^^^^ function or associated item not found in `std::ffi::OsStr`
    |
    = help: items from traits can only be used if the trait is in scope
    = note: the following trait is implemented but not in scope; perhaps add a `use` for it:
            `use std::os::wasi::ffi::OsStrExt;`

error[E0599]: no function or associated item named `from_bytes` found for struct `std::ffi::OsStr` in the current scope
   --> /home/wucke13/.cargo/git/checkouts/clap-78dbe9b58f9073fe/4b5d772/src/util/osstringext.rs:118:21
    |
118 |         Some(OsStr::from_bytes(&self.val[start..]))
    |                     ^^^^^^^^^^ function or associated item not found in `std::ffi::OsStr`
    |
    = help: items from traits can only be used if the trait is in scope
    = note: the following trait is implemented but not in scope; perhaps add a `use` for it:
            `use std::os::wasi::ffi::OsStrExt;`

error: aborting due to 31 previous errors

For more information about this error, try `rustc --explain E0599`.
error: could not compile `clap`.

To learn more, run the command again with --verbose.

[CreepySkeleton]

It's really weird. The only platform-dependent code in clap is located here, and wasm32 is covered. I'll investigate it further later.

[CreepySkeleton]

I suspect this is fixed by #1852 . @wucke13 Could you please help confirm that? Or perhaps provide precise instructions on how to reproduce this? My cargo build fails with

error[E0463]: can't find crate for `core`
  |
  = note: the `wasm32-wasi` target may not be installed

error[E0463]: can't find crate for `std`
  |
  = note: the `wasm32-wasi` target may not be installed

error: aborting due to previous error

[wucke13]

@CreepySkeleton
Regarding

error[E0463]: can't find crate for `core`
  |
  = note: the `wasm32-wasi` target may not be installed

You need to install the target, to be able to compile to it:

rustup target add wasm32-wasi

Other than that: Yes, the original error is fixed, though in exchange for a new one: the os_str_bytes crate fails to compile on wasm32-wasi. I guess, this can be circumvented at least partial, as the compiler points out that there is a use which might work:

> cargo build --target wasm32-wasi
   Compiling proc-macro2 v1.0.10
   Compiling unicode-xid v0.2.0
   Compiling version_check v0.9.1
   Compiling syn v1.0.18
   Compiling autocfg v1.0.0
   Compiling unicode-segmentation v1.6.0
   Compiling bitflags v1.2.1
   Compiling unicode-width v0.1.7
   Compiling strsim v0.10.0
   Compiling atty v0.2.14
   Compiling vec_map v0.8.1
   Compiling termcolor v1.1.0
   Compiling os_str_bytes v2.1.0
error[E0599]: no function or associated item named `from_bytes` found for struct `std::ffi::OsStr` in the current scope
   --> /home/wucke13/.cargo/registry/src/github.1485827954.workers.dev-1ecc6299db9ec823/os_str_bytes-2.1.0/src/lib.rs:243:16
    |
243 |         OsStr::from_bytes(string).map(|os_string| match os_string {
    |                ^^^^^^^^^^ function or associated item not found in `std::ffi::OsStr`
    |
    = help: items from traits can only be used if the trait is in scope
help: the following trait is implemented but not in scope; perhaps add a `use` for it:
    |
127 | use std::os::wasi::ffi::OsStrExt;
    |

error[E0599]: no method named `to_bytes` found for reference `&std::ffi::OsStr` in the current scope
   --> /home/wucke13/.cargo/registry/src/github.1485827954.workers.dev-1ecc6299db9ec823/os_str_bytes-2.1.0/src/lib.rs:251:26
    |
251 |         self.as_os_str().to_bytes()
    |                          ^^^^^^^^ method not found in `&std::ffi::OsStr`
    |
    = help: items from traits can only be used if the trait is implemented and in scope
note: `OsStrBytes` defines an item `to_bytes`, perhaps you need to implement it
   --> /home/wucke13/.cargo/registry/src/github.1485827954.workers.dev-1ecc6299db9ec823/os_str_bytes-2.1.0/src/lib.rs:185:1
    |
185 | pub trait OsStrBytes: private::Sealed + ToOwned {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error[E0599]: no function or associated item named `from_bytes` found for struct `std::ffi::OsString` in the current scope
   --> /home/wucke13/.cargo/registry/src/github.1485827954.workers.dev-1ecc6299db9ec823/os_str_bytes-2.1.0/src/lib.rs:379:19
    |
379 |         OsString::from_bytes(string).map(Into::into)
    |                   ^^^^^^^^^^ function or associated item not found in `std::ffi::OsString`
    |
    = help: items from traits can only be used if the trait is implemented and in scope
    = note: the following traits define an item `from_bytes`, perhaps you need to implement one of them:
            candidate #1: `OsStrBytes`
            candidate #2: `OsStringBytes`

error[E0599]: no function or associated item named `from_vec` found for struct `std::ffi::OsString` in the current scope
   --> /home/wucke13/.cargo/registry/src/github.1485827954.workers.dev-1ecc6299db9ec823/os_str_bytes-2.1.0/src/lib.rs:384:19
    |
384 |         OsString::from_vec(string).map(Into::into)
    |                   ^^^^^^^^ function or associated item not found in `std::ffi::OsString`
    |
    = help: items from traits can only be used if the trait is in scope
help: the following trait is implemented but not in scope; perhaps add a `use` for it:
    |
127 | use std::os::wasi::ffi::OsStringExt;
    |

error[E0599]: no method named `into_vec` found for struct `std::ffi::OsString` in the current scope
   --> /home/wucke13/.cargo/registry/src/github.1485827954.workers.dev-1ecc6299db9ec823/os_str_bytes-2.1.0/src/lib.rs:389:31
    |
389 |         self.into_os_string().into_vec()
    |                               ^^^^^^^^ method not found in `std::ffi::OsString`
    |
    = help: items from traits can only be used if the trait is in scope
help: the following trait is implemented but not in scope; perhaps add a `use` for it:
    |
127 | use std::os::wasi::ffi::OsStringExt;
    |

   Compiling lazy_static v1.4.0
error: aborting due to 5 previous errors

For more information about this error, try `rustc --explain E0599`.
error: could not compile `os_str_bytes`.

To learn more, run the command again with --verbose.
warning: build failed, waiting for other jobs to finish...
error: build failed

Edit:

Could you please help confirm that?

I can confirm that the errors decreased and changed, but there are some.

Or perhaps provide precise instructions on how to reproduce this?

I thought this was a no-brainer, please pardon me for that.

rustup target add wasm32-wasi
cargo init --bin wasm-test
cd wasm-test
echo 'clap = { git = "https://github.com/clap-rs/clap" }' >> Cargo.toml
cargo build --target wasm32-wasi

[pksunkara]

@dylni Could you look into this issue and fix it in your crate?

[CreepySkeleton]

@wucke13

I thought this was a no-brainer, please pardon me for that.

Brains may be different 😉. No problemo.

Basically, the os_str_bytes crate we rely on needs to make some assumptions on how the underlying std::ffi::OsString is represented on the target platform. It does so in a platform-specific manner, basically distinguishing between Windows and Unix.

I suspect OsString on wasm is the same as on Unix, right? If so, A small upsteam patch should do the job. Could you please provide a link to the relevant part of wasm documentation? I just have no experience with it, sorry.

[dylni]

@pksunkara This is a language limitation. There's no safe way to get anything lossless from OsStr on wasm32 targets. However, it's also not possible to receive arguments for that target, so I'm not sure how Clap could be used.

I haven't found anywhere else that OsStr is created for that target, so it might be enough to attempt a conversion to str and unwrap it as a fix. There should be no way for it to contain non-UTF-8 data if the language doesn't construct it.

[dylni]

Ignore my previous comment. I was looking at code for wasm32-unknown-unknown.

The API looks compatible with Unix, so I'll work on an update to add support for the target this week.

[dylni]

Version 2.2.0 supports this target.

[CreepySkeleton]

@dylni We are very grateful for the quick fix. Thank you a lot.

@wucke13 After the PR is merged, could you please confirm that the build is actually fixed?

[dylni]

@CreepySkeleton No problem. I would prefer that it supports as many targets as possible.

I think all buildable targets that take arguments are covered now (except sgx), but let me know if you find any others.