As mentioned in the comment the historical behavior is because pressing unknown
control characters like Ctrl+4 inserts confusing characters, so let's back
out that part of b77d1d0e2 (Stop crashing on invalid Unicode input, 2024-02-27).
We still have the code for rendering control characters, for pasted text,
or text recalled from history. It is unclear whether we should strip those.
Some terminals already strip control characters from pasted text -- but not
all of them: see https://codeberg.org/dnkl/foot/pulls/312 for example which
has a follow up called "Don't strip HT when pasting in non-bracketed mode".
Don't force the internal use of `RefCell<T>`, let the caller place that into
`MainThread<>` manually. This lets us remove the reference to `MainThread<>`
from the definition of `Screen` again and reduces the number of
`assert_is_main_thread()` calls.
Fairly straightforward, with the only unfortunate part of this being that
`Screen` isn't as pure and now encodes the facte that we use it with
main-thread-only stdout `Outputter`.
Unlike C++, Rust requires "char" to be a valid Unicode code point. As a
workaround, we take the raw (probably UTF-8-encoded) input and convert each
input byte to a char representation from the private use area (see commit
3b15e995e (str2wcs: encode invalid Unicode characters in the private use
area, 2023-04-01)). We convert back whenever we output the string, which
is correct as long as the encoding didn't change since the data was input.
We also need to convert keyboard input; do that.
Quick testing shows that our reader drops PUA characters. Since this patch
converts both invalid Unicode input as well as PUA input into a safe PUA
representation, there's no longer a reason to not add PUA characters to
the commandline, so let's do that to restore traditional behavior.
Render them as � (REPLACEMENT CHARACTER); unfortunately we show one per
input byte instead of one per code point. To fix this we probably need our
own char type.
While at it, remove some special cases that try to prevent insertion of
control characters. I don't think they are necessary. Could be wrong..
Commit e5b34d5cd (Suppress autosuggesting during backspacing like browsers do,
2012-02-06) disabled autosuggestion when backspacing. Autosuggestions are
re-enabled whenever we insert anything in the command line. Undo uses a
different code path to insert into the command line, which does not re-enable
autosuggestion.
Fix that.
Also re-enable autosuggestion when undo erases from the command line.
This seems like the simplest approach. It's not clear if there's a better
behavior; browsers don't agree on one in any case.
Currently, if you enter `echo` and press up-arrow, it might select
e.g. `echo foo`.
You can then enter text, making it `echo foobar` and press up-arrow
again, but the search string is *still* `echo`.
Many *other* input functions will end history search, including e.g.
expand-abbr, so pressing space by default will already end it.
So this ends the history search once you input something.
Incidentally this allows suggestions to work in this case, so it
Fixes#10287
Note that autosuggestions have been disabled while history search is
active since a08450bcb6, I'm not sure
it's actually *needed*, so it would also be possible to enable it in
that case.
But since this is already awkward (history search is *active* but with
the old search string) and I'm not sure if e.g. suggestions during
history search would be too busy, let's do this first.
Commit 5f849d0 changed control-C to print an inverted ^C and then a newline.
The original motivation was
> In bash if you type something and press ctrl-c then the content of the line
> is preserved and the cursor is moved to a new line. In fish the ctrl-c just
> clears the line. For me the behaviour of bash is a bit better, because it
> allows me to type something then press ctrl-c and I have the typed string
> in the log for further reference.
This sounds like a valid use case in some scenarios but I think that most
abandoned commands are noise. After all, the user erased them. Also, now that
we have undo that can be used to get back a limited set of canceled commands.
I believe the original motivation for existing behavior (in other shells) was
that TERM=dumb does not support erasing characters. Similarly, other shells
like to leave behind other artifacts, for example when using tab-completion
or in their interactive menus but we generally don't.
Control-C is the obvious way to quickly clear a multi-line commandline.
IPython does the same. For the other behavior we have Alt-# although that's
probably not very well-known.
Restore the old Control-C behavior of simply clearing the command line.
Our unused __fish_cancel_commandline still prints the ^C. For folks who
have explicitly bound ^C to that, it's probably better to keep the existing
behavior, so let's leave this one.
Previous attempt at #4713 fizzled.
Closes#10213
