Some terminals such as conhost and putty cannot parse DCS commands,
and will echo them back.
Work around this by making sure that this echoed text will not
be visible.
Do so by temporarily enabling the alternative screen buffer when
sending DCS queries (in this case only XTGETTCAP). The alternative
screen buffer feature seems widely supported, and easier to get right
than trying to clear individual lines etc.
The alternative screen may still be visible for a
short time. Luckily we can use [Synchronized Output](
https://gist.github.com/christianparpart/d8a62cc1ab659194337d73e399004036)
to make sure the screen change is never visible to the user.
Querying support for that is deemed safe since it only requires a
CSI command.
Note that it seems that every terminal that supports Synchronized
Output also parses DCS commands successfully. This means that we
could get away without the alternative screen buffer in practice.
Not sure yet.
The implementation is slightly more complex than necessary in that it
defines a redundant ImplicitEvent. This is for two reasons: 1. I have
a pending change that wants to use it, so this removes diff noise and
2. we historically have sc/input_common.rs not depend on src/output.rs.
I dont' think any are strong reasons though.
Commit b6d76ae: we now use lines like "# RUN: fish=%fish %fish".
If a test exits with 127 we try to look up the command but use the
wrong name, which leads to unintelligible errors if the test exits
with 127 for other reasons.
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
Some terminals like the Linux console don't support indn (scroll
forward). Let's query for the presence of these features, and fall
back to the traditional behavior if absent.
For now, break with the tradition of using the terminfo database that
we read ourselves. Instead ask the terminal directly via XTGETTCAP.
This is a fairly young feature implemented by terminals like xterm,
foot and kitty, however xterm doesn't expose these capabilities at
this point.
This is a good opportunity to try XTGETTCAP, since these are
capabilities we haven't used before. Advantages of XTGETTCAP are that
it works across SSH and is independent of $TERM (of course ignoring
$TERM may also be breaking to some users). Let's see if it sees
adoption in practice.
Tested to work on foot and kitty, allowing the default ctrl-l binding
to work without erasing any screen content.
See #11003
The new ctrl-l implementation relies on Cursor Position Reporting (CPR)
This may not work on exotic terminals that don't support CSI 6n yet
As a workaround, probe for this feature by sending a CSI 6n (CPR)
on startup. Until the terminal responds, have scrollback-push fall
back to clear-screen.
The theoretical problem here is that we might handle scrollback-push
before we have handled the response to our feature probe. That seems
fairly unlikely; also e49dde87cc has the same characteristics.
This could query a capability instead (via XTGETTCAP or otherwise)
but I haven't found one; and this seems at least as reliable.
While at it, change the naming a bit.
See #11003
After we query kitty keyboard protocol support,
we send CSI 5n, to also receive a response if
the protocol is not supported.
However we don't bother to wait for the response, so this extra
message is not really useful (only to get better logs). Remove it.
With tmux 3.0 (from 2019) inside SSH, the CSI 5n response is echoed.
I guess with all other terminals we were just lucky. Move it to
right after where we disable ECHO I guess.
In general, asynchronous requests create a lot of potential for error,
we should try to get away from them.
These aren't typically used in the terminal but they are present on
many keyboards.
Also reorganize the named key constants a bit. Between F500 and
ENCODE_DIRECT_BASE (F600) we have space for 256 named keys.
To make it more familiar to vi/vim users.
In all mode, ctrl-k is bind to kill-line.
In Vi visual mode:
* press v or i turn into normal or insert mode respectively.
* press I turn to insert mode and move the cursor to beginning of line.
* because fish doesn't have upcase/locase-selection, and most people reach for
g-U rather than g-u, g-U binds to togglecase-selection temporarily.
Testing has revealed some problems on BSD and Windows terminals and
the Linux Console, let's revert to the old implementation until these
are fixed. Leaving the changelog entry for now since it shouldn't
take long.
See #11003
The FdReadableSet api was always intended to be converted to use Duration
instead of usec/msec once the ffi was removed. This lets us be explicit about
forever/infinite timeouts and removes the (small) chance of a collision between
u64::MAX and INFINITE.
I tried this out with `type Timeout = Option<Duration>` (only without the alias)
but was unhappy with easy it is to accidentally use `None` when you meant a
timeout of zero.
Commit 1c4e5cadf2 (Autosuggestions in multi-line
command lines, 2024-12-15) accidentally passed an empty
"commandline_before_suggestion" to compute_layout() when there is
no autosuggestion.
Closes#10996
As reported in
https://github.com/fish-shell/fish-shell/issues/10992#issuecomment-2568954940,
the user may reset the terminal and run scrollback-push without
repainting in between. This means that the terminal will report
the cursor position y=0 x=0 which doesn't match what fish renders.
Fortunately, y=0 is a safe fallback value for the scrollback-push
use case.
While at it, fix an off-by-one error in a log.
Before 1c4e5cadf2 (Autosuggestions in multi-line command lines,
2024-12-15), the completion code path in the autosuggestion performer
used to do something weird: it used to request completions for the
entire command line (with the implied cursor at end) but try to apply
the same completion at the actual cursor.
That commit changed this to request completions only up to the cursor
position, which could in theory make us produce valid completions even
if the cursor is not at end of the line. However, that doesn't really
work since autosuggestions can only be rendered at the end of the line.
And the worst of it, that commit tries to compute
line_at_cursor(&full_line, search_string_range.end)
which crashes as out-of-bounds if the completion needs to replace the token
(like a case-correcting completion does).
Let's apply completions to the end, matching how autosuggestions work
in general.
I believe it's possible that the cursor position reported by the
terminal does not match fish's cursor. In that case, overflow. Fix
that since we should not trust the terminal.
Also rename a confusingly named variable.
Mouse-click handling has a similar issue, fix that too.
FWIW, tmux always reports cursor position zero (\x1b[1;1R) when
querying from fish (but not when querying with printf).
Will investigate that next, see the linked issue.
Fixes#10992
