For backwards compatibility, fish does not treat "{echo,hello}" as a compound
statement but as brace expansion (effectively "echo hello"). We interpret
"{X...}" as compound statement only if X is whitespace or ';' (which is an
interesting solution).
A brace expansion at the very start of a command
is usually pointless (space separation is shorter).
The exception are cases where the command name and the first few arguments
share a suffix.
$ {,1,2,3,4}echo
1echo 2echo 3echo 4echo
Not sure if anyone uses anything like that. Perhaps we want to trade
compatibility for simplicity. I don't have a strong opinion on this.
Always parse the opening brace as first character of a command token as
compound statement.
Brace expansion can still be used with a trick like: «''{echo,foo}»
Closes#11477
I think `set_color ff0000` should default to outputting true-color sequences.
Unfortunately there is no good and widely-supported way to query for true-color
support. `COLORTERM=truecolor` doesn't work in some cases such as ssh.
Since many terminals nowadays implement the RGB sequences, let's try using
them by default.
Note that Emacs's ansi-term implements truecolor now.
See also the discussion around
https://github.com/fish-shell/fish-shell/pull/11345#issuecomment-2794920900Closes#11372
Our use of the terminfo database in /usr/share/terminfo/$TERM is both
1. a way for users to configure app behavior in their terminal (by
setting TERM, copying around and modifying terminfo files)
2. a way for terminal emulator developers to advertise support for
backwards-incompatible features that are not otherwise easily observable.
To 1: this is not ideal (it's very easy to break things). There's not many
things that realistically need configuration; let's use shell variables
instead.
To 2: in practice, feature-probing via terminfo is often wrong. There's not
many backwards-incompatible features that need this; for the ones that do
we can still use terminfo capabilities but query the terminal via XTGETTCAP
directly, skipping the file (which may not exist on the same system as
the terminal).
---
Get rid of terminfo. If anyone finds a $TERM where we need different behavior,
we can hardcode that into fish.
* Allow to override this with `fish_features=no-ignore-terminfo fish`
Not sure if we should document this, since it's supposed to be removed soon,
and if someone needs this (which we don't expect), we'd like to know.
* This is supported on a best-effort basis; it doesn't match the previous
behavior exactly. For simplicity of implementation, it will not change
the fact that we now:
* use parm_left_cursor (CSI Ps D) instead of cursor_left (CSI D) if
terminfo claims the former is supported
* no longer support eat_newline_glitch, which seems no longer present
on today's ConEmu and ConHost
* Tested as described in https://github.com/fish-shell/fish-shell/pull/11345#discussion_r2030121580
* add `man fish-terminal-compatibility` to state our assumptions.
This could help terminal emulator developers.
* assume `parm_up_cursor` is supported if the terminal supports XTGETTCAP
* Extract all control sequences to src/terminal_command.rs.
* Remove the "\x1b(B" prefix from EXIT_ATTRIBUTE_MODE. I doubt it's really
needed.
* assume it's generally okay to output 256 colors
Things have improved since commit 3669805627 (Improve compatibility with
0-16 color terminals., 2016-07-21).
Apparently almost every actively developed terminal supports it, including
Terminal.app and GNU screen.
* That is, we default `fish_term256` to true and keep it only as a way to
opt out of the the full 256 palette (e.g. switching to the 16-color
palette).
* `TERM=xterm-16color` has the same opt-out effect.
* `TERM` is generally ignored but add back basic compatiblity by turning
off color for "ansi-m", "linux-m" and "xterm-mono"; these are probably
not set accidentally.
* Since `TERM` is (mostly) ignored, we don't need the magic "xterm" in
tests. Unset it instead.
* Note that our pexpect tests used a dumb terminal because:
1. it makes fish do a full redraw of the commandline everytime, making it
easier to write assertions.
2. it disables all control sequences for colors, etc, which we usually
don't want to test explicitly.
I don't think TERM=dumb has any other use, so it would be better
to print escape sequences unconditionally, and strip them in
the test driver (leaving this for later, since it's a bit more involved).
Closes#11344Closes#11345
Text like "simply do" or "just press" is patronizing and unnecessary.
The prose is nicer if it's removed, and in some cases other words are
more specific.
Something like "we'll pretend your prompt is just a ``>``" can stay.
e697add5b5 (Feature flag to prevent executing off buffered keys, 2025-01-02)
breaks my expectations/habits, and it breaks Midnight Commander.
Additionally, I'm not aware of any case where it actually adds security.
We generally assume that terminal echoback sequences do not contain
control characters except for well-known escape sequences.
This backs out commit e697add5b5.
See #10987, #10991
The current limit can be reached in actual use and still be a usable shell.
E.g. in #11095 someone had `git status` print over 100MiB of file
information.
The version where a feature became the default is now described inline,
to make it a single source of truth. I could have fixed the other
section where this was described, but this seemed easier.
I also removed a few details that seem no longer relevant.
If I run "sleep 3", type a command and hit enter, then there is no
obvious way to cancel or edit the imminent command other than ctrl-c
but that also cancels sleep, and doesn't allow editing. (ctrl-z sort
of works, but also doesn't allow editing).
Let's try to limit ourselves to inserting the buffered command
(translating enter to a newline), and only execute once the user
actually presses enter after the previous command is done.
Hide it behind a new feature flag for now.
By making things less scary, this might be more user-friendly, at
the risk of breaking expectations in some cases.
This also fixes a class of security issues where a command like
`cat malicious-file.txt` might output escape sequences, causing
the terminal to echo back a malicious command; such files can still
insert into the command line but at least not execute it directly.
(Since it's only fixed partially I'm not really sure if the security
issue is a good enough motivation for this particular change.)
Note that bracketed paste probably has similar motivation as this feature.
Part of #10987Closes#10991
This tries to open the given file to use as stdin, and if it fails,
for any reason, it uses /dev/null instead.
This is useful in cases where we would otherwise do either of these:
```fish
test -r /path/to/file
and string match foo < /path/to/file
cat /path/to/file 2>/dev/null | string match foo
```
This both makes it nicer and shorter, *and* helps with TOCTTOU - what if the file is removed/changed after the check?
The reason for reading /dev/null instead of a closed fd is that a closed fd will often cause an error.
In case opening /dev/null fails, it still skips the command.
That's really a last resort for when the operating system
has turned out to be a platypus and not a unix.
Fixes#4865
(cherry picked from commit df8b9b7095)
This introduces a feature flag, "test-require-arg", that removes builtin test's zero and one argument special modes.
That means:
- `test -n` returns false
- `test -z` returns true
- `test -x` with any other option errors out with "missing argument"
- `test foo` errors out as expecting an option
`test -n` returning true is a frequent source of confusion, and so we are breaking with posix in this regard.
As always the flag defaults to off and can be turned on. In future it will default to on and then eventually be made read-only.
There is a new FLOG category "deprecated-test", run `fish -d deprecated-test` and it will show any test call that would change in future.
This seems a bit better because it's what bind uses. To makes sure that
something like :kbd:`ctrl-x` looks good in HTML, remove the border from the
kbd style. Else both "ctrl" and "x" get small boxes which looks weird.
This is the last remnant of the old percent expansion.
It has the downsides of it, in that it is annoying to combine with
anything:
```fish
echo %self/foo
```
prints "%self/foo", not fish's pid.
We have introduced $fish_pid in 3.0, which is much easier to use -
just like a variable, because it is one.
If you need backwards-compatibility for < 3.0, you can use the
following shim:
```fish
set -q fish_pid
or set -g fish_pid %self
```
So we introduce a feature-flag called "remove-percent-self" to turn it
off.
"%self" will simply not be special, e.g. `echo %self` will print
"%self".
