Re: [PATCH 0/25] detecting &&-chain breakage

On Sat, Mar 21, 2015 at 11:01:43AM -0700, Junio C Hamano wrote:

quoted

Running:

  git diff origin origin/jk/test-chain-lint |
  perl diff-blame.pl jk/test-chain-lint |
  grep EOF

was fun. At least I am not the only one. :)

The parameter to diff-blame.pl should be origin, instead of
jk/test-chain-lint, I presume?  You are grabbing the preimage line
numbers and asking blame to find out who wrote them.

Yes, sorry, that was an error translating from what I actually ran in
the shell into the email. It should be "origin". And if the script
really wanted to be user-friendly, it should probably take two endpoints
and just run the diff itself (when I started it, I assume that you could
process any diff, but of course you must know the start point to get a
reasonable blame).

quoted

Nor the worst in the "severe" category.

I do not quite get what this means---the script does not seem to
judge what is severe and what is not, so I presume that this is to
be judged by whoever is reading the output from the above pipeline
after replacing "grep EOF" with "less" or something?

That was the exercise I left to the reader. :) In this case, it is
possible because I have already split the patches into "severe",
"moderate", and "trivial" cases, so you can blame only the severe patch
(using its parent as the start-point).

quoted

while (<STDIN>) {
  if (m{^--- .*?/(.*)}) {

This may match a removal of a line that begins with "^-- something/" ;-)

True. I was trying to avoid being stateful in my diff parsing. I guess
it would be enough to parse the hunk headers to know how many lines are
in the hunk. Not worth it for this one-off, but a good thing if somebody
wanted to pick this idea up for a "real" tool.

quoted

  # XXX coalesce blocks of adjacent lines into ranges?
  system(qw(git --no-pager blame), @ARGV,

You may want to pass an option to always show the filename here.

I left that to the user. I actually found "--line-porcelain" useful for
gathering statistics (e.g., piped to "grep '^author ' | sort | uniq -c").

-Peff