"tail -c 16" syntax in crypt/clean throws an error

[ljm42]

# git add myfile
tail: cannot open '16' for reading: No such file or directory
hex string is too short, padding with zero bytes to length
*** WARNING : deprecated key derivation used.
Using -iter or -pbkdf2 would be better.

The issue is in this line of crypt/clean: https://github.com/elasticdog/transcrypt/blob/0396245e6a1e238c4a08d0b89271f2490c4ec559/transcrypt#L299

On my system at least, "tail -c 16" is not valid, but other options work:

# echo "09876543210987654321" | tail -c 16
tail: cannot open '16' for reading: No such file or directory
# echo "09876543210987654321" | tail -c16
543210987654321
# echo "09876543210987654321" | tail --bytes=16
543210987654321

FYI:

# tail --version
tail (GNU coreutils) 8.32

[jmurty]

Hi @ljm42 thanks for the report, that's a surprising edge case.

Are you new to using transcrypt? I don't think the format of the tail -c command is something we have changed recently, but maybe that's been a problem case for a while and we didn't realise.

And can you please check whether a command like head -c 8 has the same problem on your system? We use that command in the pre-commit hook that's new in version 2.1.0.

[jmurty]

Hi @ljm42 could you also please test the potential fix on this branch? https://github.com/elasticdog/transcrypt/compare/94-more-compatible-head-and-tail-bytes-commands

That branch removes the space between the -c switch and value for the tail command you mention, and for a similar head command in the pre-commit hook script.

[ljm42]

Thanks! yes I'm new to transcrypt :)

Interestingly, head doesn't have the same issues as tail:

#echo "12345678901234567890" | head -c 8
12345678
#echo "12345678901234567890" | head -c8
12345678
#echo "12345678901234567890" | head --bytes=8
12345678

# head --version
head (GNU coreutils) 8.32

This version of the file: https://raw.githubusercontent.com/elasticdog/transcrypt/25c3c66522d4cc56e11a32adcb8dbcb9458bb7f9/transcrypt does allow me to "git add" without the tail error, thanks!

# git add testfile
*** WARNING : deprecated key derivation used.
Using -iter or -pbkdf2 would be better.

~But I'm not sure that everything is working yet. Should "git show" automatically run the smudge filter?~ Moved this question to #96

[jmurty]

Thanks for confirming the tail -c fix @ljm42 I have merged this change to be included in a future release.