[Buildroot] [PATCH 1/1] support/testing/infra/emulator.py: prevent the commands from wrapping
Peter Korsgaard
peter at korsgaard.com
Sat Oct 9 11:28:57 UTC 2021
>>>>> "Edgar" == Edgar Bonet <bonet at grenoble.cnrs.fr> writes:
> Traditional VT-10x terminals (and their emulators) have a "magic
> margins" feature that enables the last character position to be updated
> without scrolling the screen: whenever a character is printed on the
> last column, the cursor stays over the character, instead of moving to
> the next line.
> The Busybox shell, ash, attempts to defeat this feature by printing
> CF,LF right after echoing a character to the last column.[1] This
> doesn't play well with emulator.py. The run() method of the Emulator
> class captures the output of the emulated system and assumes the first
> line it reads is the echo of the command, and all subsequent lines are
> the command's output. If the line made by the command + shell prompt is
> longer than 80 characters, then it is echoed as two or more lines, and
> all but the first one are mistaken for the command's output.
> We fix this by telling the emulated system that we are using an
> ultra-wide terminal with 29999 columns. Larger values would be ignored
> and replaced by the default, namely 80 columns.[2]
> [1] https://git.busybox.net/busybox/tree/libbb/lineedit.c?h=1_34_0#n412
> [2] https://git.busybox.net/busybox/tree/libbb/xfuncs.c?h=1_34_0#n258
> Signed-off-by: Edgar Bonet <bonet at grenoble.cnrs.fr>
> Reported-by: Thomas Petazzoni <thomas.petazzoni at bootlin.com>
> Co-authored-by: Yann E. MORIN <yann.morin.1998 at free.fr>
> ---
> support/testing/infra/emulator.py | 2 ++
> 1 file changed, 2 insertions(+)
> Note that I tested that the command
> stty columns 29999
> does fix the wrapping behavior on an actual board, while using a serial
> connection. I did not test the script emulator.py, as I am unfamiliar
> with the testing infrastructure. Would someone volunteer to do that
> test?
Committed to 2021.02.x, 2021.05.x and 2021.08.x, thanks.
--
Bye, Peter Korsgaard
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