Mercurial hook to disallow committing large binary files

Question

I want to have a Mercurial hook that will run before committing a transaction that will abort the transaction if a binary file being committed is greater than 1 megabyte. I

Answer 1

This is really easy to do in a shell hook in recent Mercurial:

if hg locate -r tip "set:(added() or modified()) and binary() and size('>100k')"; then
  echo "bad files!"
  exit 1
else
  exit 0
fi

What's going on here? First we have a fileset to find all the changed files that are problematic (see 'hg help filesets' in hg 1.9). The 'locate' command is like status, except it just lists files and returns 0 if it finds anything. And we specify '-r tip' to look at the pending commit.

Answer 2

for f in ctx.files() will include removed files, you need to filter those out.

(and you can replace for rev in range(ctx.rev(), tip+1): by for rev in xrange(ctx.rev(), len(repo)):, and remove tip = ...)

If you're using a modern hg, you don't do ctx = context.changectx(repo, node) but ctx = repo[node] instead.