Recently nsSidebar.js in browser/components/sidebar/src/ was changed to being preprocessed. This change, when rebuilt in an existing tree, caused nsSidebar.js in the *srcdir* to end up blank. (peterv checked this in when checking in a large tree-wide change; I hit it in my tree as well.) Steps to reproduce: 1. edit browser/components/sidebar/src/Makefile.in to change EXTRA_PP_COMPONENTS to EXTRA_COMPONENTS 2. run make in objdir 3. undo edit to makefile in 4. run make in objdir Actual results: nsSidebar.js is empty Expected results: No change to nsSidebar.js I think the bug here is a bug in the handling of EXTRA_PP_COMPONENTS: it redirects the output to the destination without removing it first. If the destination is a symlink, that can be bad, because; $ set +o noclobber $ cat > foo hello $ ln -s foo bar $ ls -l total 12 lrwxrwxrwx 1 dbaron dbaron 3 2007-03-09 10:33:13 bar -> foo -rw-rw-r-- 1 dbaron dbaron 6 2007-03-09 10:33:10 foo $ cat > bar $ ls -l total 8 lrwxrwxrwx 1 dbaron dbaron 3 2007-03-09 10:33:13 bar -> foo -rw-rw-r-- 1 dbaron dbaron 0 2007-03-09 10:33:25 foo

For what it's worth, the bug that triggered the problem was bug 332753.

I assume this also applies to the microsummaries service?

The microsummary service was always preprocessed. This bug is a bug in builds that didn't clobber dist on a tree that had previously been built when the file was not preprocessed.

This caused the bustage on two unit-testing tinderboxen that appeared today after a checkin I made for bug 279698, because the nsSidebar.js on the tinderboxen got truncated to nothing. It also caused my truncation of <toolkit/components/console/jsconsole-clhandler.js> to nothing instead of making the change I intended to make. Consequently, I'm upping this bug's severity.

Comment on attachment 258005 [details] [diff] [review] patch please indent this <tab><space><space> instead of <tab><tab>, to match what existing convention there is.

Hrm -- the existing convention in the file seems to be almost evenly split between those two patterns, but I'll switch since you seem to prefer it (although I prefer <tab><tab>).

Checked in to trunk.