Wrong ESC-sequences for F-keys F1-F4

[dimitrik-fr]

Describe the bug
Both xtrerm-kettyand xterm-256color terminfo are having F1-F4 keys as :

• F1: kf1=\EOP
• F2: kf2=\EOQ
• F3: kf3=\EOR
• F4: kf4=\EOS

while kitty is returning on these keys pressing the following :

• F1 : \EP
• F2 : \EQ
• F3 : \ER
• F4 : \ES

e.g. there was somewhere missed "O" in output sequences..
and, curiously, this is happening only with F1-F4 keys, any other F-keys are working just fine.

To Reproduce

you can observe the problem with any Terminal app which is able to report pressed keys, and for me the most simple is to use "micro" for this :

1. start "micro" in kitty
2. type Ctrl-e
3. type raw in command line
4. now type any F-key and observe the received ESC-sequence
5. check F1-F4 keys, etc.
6. type Ctrl-q to leave "raw" mode
7. type Ctrl-q to leave "micro"

Expected behavior
the expected behavior is to see the sequences matching terminfo.

Environment details
OS: OSX Catalina (but I don't think OS plays any role here)

[kovidgoyal]

I cannot replicate this with kitty 0.20.3, running:

kitty --config=NONE kitty +kitten show_key -m application

and pressing F1 correctly displays

^[OP

as expected.

[kovidgoyal]

Oh and just for completeness, same without using the showkey kitten

printf '\x1b[?1h'; cat -v

also prints ^[OP as expected for F1

[dimitrik-fr]

Hmm.. -- seems like you're right (and probably there are some issues in "micro" then)..

also, to have "third party" test check, I've also tried "vi", and it was printing when F2, F3, F4 are pressed, so I'll open a bug report for "micro", let's see..

thank you for prompt support !

Rgds, -Dimitri

[trygveaa]

If you don't set the terminal in Application Cursor Keys mode (don't print \x1b[?1h), kitty will send ^[[P instead of ^[OP and so on, so I assume micro doesn't set it in this mode.

@kovidgoyal: Why does Application Cursor Keys mode change the function keys, not just the arrow keys in kitty? E.g. xterm sends ^[OP for F1 regardless of this mode.

[kovidgoyal]

Ah, that is indeed a regression, although note that cursor key mode
affects the cursor keys, home, end and the KP_BEGIN key. Just not F1-F4 :)

[trygveaa]

note that cursor key mode affects the cursor keys, home, end and the KP_BEGIN key

Right, "just the arrow keys" wasn't completely accurate.