Automating Coverity, was Re: [PATCH 00/26] Address a couple of issues identified by Coverity

[Johannes Schindelin <Johannes.Schindelin@gmx.de>]

Hi Stefan,

On Fri, 28 Apr 2017, Stefan Beller wrote:

> On Thu, Apr 27, 2017 at 3:50 PM, Johannes Schindelin
> <Johannes.Schindelin@gmx.de> wrote:
> 
> > I still have to find the time to figure out one more detail: how to
> > download and extract the Coverity tool (the .zip archive has a
> > variable name for the top-level directory), and doing that only every
> > once in a while, say, only when there is no previously unpacked tool,
> > or it is already 4 weeks old.
> 
> That is an interesting problem, which I ignored as the older versions of
> their tools still works once they release new versions. So I just
> manually check every once in a while if they have new versions out
> there.
> 
> So if you find a nice solution to that problem, let me know, please.

I think I have a working idea (jotting it down in the editor, untested):

	init_or_update_coverity_tool () {
		# check once per week whether there is a new version
		coverity_tool=.git/coverity-tool/
		test ! -d $coverity_tool ||
		test $(($(date +%s)-$(stat -c %Y $coverity_tool))) -gt
			$((7*24*60*60)) ||
		return

		curl --form "token=$(COVERITY.TOKEN)" \
			--form "project=git-for-windows" \
			--time-cond .git/coverity_tool.zip \
			-o .git/coverity_tool.zip.new \
			https://scan.coverity.com/download/win64 &&
		test -f .git/coverity_tool.zip.new || {
			# Try again in a week
			touch $coverity_tool
			return
		}

		mv -f .git/coverity_tool.zip.new .git/coverity_tool.zip ||
		die "Could not overwrite coverity_tool.zip"

		mkdir $coverity_tool.new &&
		(cd $coverity_tool.new &&
		 unzip ../coverity_tool.zip) ||
		die "Could not unpack coverity_tool.zip"

		rm -rf $coverity_tool &&
		mv $coverity_tool.new $coverity_tool ||
		die "Could not switch to new Coverity tool version"
	}

	init_or_update_coverity_tool
	PATH=$(echo $coverity_tool/*/bin):$PATH

I guess I will start from that snippet once I have time to work on that
Coverity automation.

BTW I stumbled over an interesting tidbit today: if you define FLEX_ARRAY
outside of git-compat-util.h, it will not be overridden by Git. That is,
if you want to use 64kB flex arrays by default, you can call

	make CPPFLAGS=-DFLEX_ARRAY=65536

No need to patch the source code.

Ciao,
Dscho