This reduces noise in the upcoming "Port execution" commit.
I accidentally made IoStreams a "class" instead of a "struct". Would be
easy to correct that but this will be deleted soon, so I don't think we care.
C++ main used getopt (no w!), which appears to internally print
error-messages. The Rust version will use `wgetopter_t`, and therefore needs to
print this itself.
This is an alternative to the very common pattern of
```rust
streams.err.append(output);
streams.err.append1('\n');
```
Which has negative performance implications, see https://github.com/fish-shell/fish-shell/pull/9229
It takes `Into<WString>` to hopefully avoid allocating anew when the argument is
a WString with leftover capacity
- Add test to verify piped string replace exit code
Ensure fields parsing error messages are the same.
Note: C++ relied upon the value of the parsed value even when `errno` was set,
that is defined behaviour we should not rely on, and cannot easilt be replicated from Rust.
Therefore the Rust version will change the following error behaviour from:
```shell
> string split --fields=a "" abc
string split: Invalid fields value 'a'
> string split --fields=1a "" abc
string split: 1a: invalid integer
```
To:
```shell
> string split --fields=a "" abc
string split: a: invalid integer
> string split --fields=1a "" abc
string split: 1a: invalid integer
```
This adopts the new function store, replacing the C++ version.
It also reimplements builtin_function in Rust, as these was too coupled to
the function store to handle in a separate commit.
Note this is slightly incomplete - the FD is not moved into the parser, and so
will be freed at the end of each directory change. The FD saved in the parser is
never actually used in existing code, so this doesn't break anything, but will
need to be corrected once the parser is ported.
This restores the status quo where builtins are like external commands
in that they can't see anything after a 0x00, because that's the c-style
string terminator.
* Make NULs work for builtins
This switches from passing a c-string to output_stream_t::append to
passing a proper string.
That means a builtin that prints a NUL no longer crashes with "thread '' panicked
at 'String contained intermediate NUL character: ".
Instead, it will actually handle the NUL, even as an argument.
That means something like
`echo foo\x00bar` will now actually print a NUL instead of truncating
after the `foo` because we passed c-strings around everywhere.
The former is *necessary* for e.g. `string`, the latter is a change
that on the whole makes dealing with NULs easier, but it is a
behavioral change.
To restore the c-string behavior we would have to truncate arguments
at NUL.
See #9739.
* Use AsRef instead of trait bound
This is basically a subset of type, so we might as well.
To be clear this is `command -s` and friends, if you do `command grep` that's
handled as a keyword.
One issue here is that we can't get "one path or not" because I don't
know how to translate a maybe_t? Do we need to make it a shared_ptr instead?
