perf(runtime): fix strace regex

[fedemengo]

I think this regex can be simplified with no undesired effects.

When opening text file with long lines of numbers (bitstrings in my case) the additional and optional [0-9:.]* * put unnecessary work on the regex engine.

Honestly I don't see any reason why the regex should have the additional pattern. The two tests works fine with the simplified version

[fedemengo]

@brammool do you see any value in this?

[brammool]

Federico Mengozzi wrote:

I think this regex can be simplified with no side effects apart from an improvement in performance. When opening text file with long lines of numbers (bitstrings in my case) the additional and optional `[0-9:.]* *` put unnecessary work on the regex engine. This is even more true in neovim, whose lua regex engine is not as good as vim. Honestly I don't see any reason why the regex should have the additional pattern. The two tests works fine with the simplified version

Hmm, I'm not 100% sure this won't cause problems. execve() is also used in C programs at least. To avoid changing the functionality and still have nearly all of the performance improvement, we can first check for a match with "execve(" and only then check for the current pattern: elseif (line1 =~ 'execve(' && line1 =~ '[0-9:.]* *execve(') || line1 =~ '^__libc_start_main' How about that?

…

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[fedemengo]

@brammool I think that would definitely be better, however I'm not sure it's really required since the additional [0-9:.]* * is optional. It's not really changing the result of the simpler regex.

For example, with this config .vimrc

filetype on

a file with this line

execve()

it's already being recognised as strace type. This is the output after set ft=?

That's why I was thinking we could either drop the [0-9:.]* * or we need to fix it up a bit. I think this regex used to be more specific at some point

https://github.com/vim/vim/blame/875feea6ce223462d55543735143d747dcaf4287/runtime/scripts.vim#L305

[brammool]

@brammool I think that would definitely be better, however I'm not sure it's really required since the additional `[0-9:.]* *` is optional. It's not really changing the result of the simpler regex. For example, with this config `.vimrc` ``` filetype on ``` a file with this line ``` execve() ``` it's already being picked with as `strace` type.

Right, it appears this pattern was already faulty. I guess a "^" should have been at the start. That way, if "execve" would be preceded by something else than a timestamp it would not match. So it would need to be: ``` elseif (line1 =~ 'execve(' && line1 =~ '^[0-9:.]* *execve(') || line1 =~ '^__libc_start_main' ``` To avoid false matches. This would still be fast.

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[fedemengo]

@brammool I changed the line as you suggested. I added a small test too. LMK if this works

[codecov]

Codecov Report

Merging #12220 (2e65587) into master (cde8de0) will increase coverage by 0.00%.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master   #12220   +/-   ##
=======================================
  Coverage   81.95%   81.95%           
=======================================
  Files         164      164           
  Lines      194112   194142   +30     
  Branches    43831    43836    +5     
=======================================
+ Hits       159079   159117   +38     
+ Misses      22195    22193    -2     
+ Partials    12838    12832    -6     

Flag	Coverage Δ
huge-clang-none	82.68% <ø> (+0.03%)	⬆️
huge-gcc-none	53.86% <ø> (+0.01%)	⬆️
huge-gcc-testgui	51.98% <ø> (+0.01%)	⬆️
huge-gcc-unittests	0.29% <ø> (ø)
linux	82.40% <ø> (-0.01%)	⬇️
mingw-x64-HUGE	76.55% <ø> (-0.01%)	⬇️
mingw-x86-HUGE	77.00% <ø> (-0.02%)	⬇️
windows	78.13% <ø> (-0.02%)	⬇️

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