Re: [PATCH] checkpatch.pl: Add SPDX license tag check

[Joe Perches <joe@perches.com>]

On Thu, 2017-11-09 at 12:12 -0600, Rob Herring wrote:
> On Thu, Nov 9, 2017 at 9:39 AM, Joe Perches <joe@perches.com> wrote:
> > On Thu, 2017-11-09 at 07:47 -0600, Rob Herring wrote:
> > > On Wed, Nov 8, 2017 at 8:10 PM, Joe Perches <joe@perches.com> wrote:
> > > > On Wed, 2017-11-08 at 19:10 -0600, Rob Herring wrote:
> > > > > Add a check warning if SPDX-License-Identifier tags are not used in
> > > > > newly added files.
> > > > 
> > > > If this is to be done, and I think it's not a great idea,
> > > 
> > > Which part? SPDX tags or checking new files or just using checkpatch for this?
> > 
> > SPDX tags in all files.

Is having an SPDX tag in every file really desired?

> > 
> > There's no real way to check a patch for this.
> > 
> > You have to check the entire file.
> 
> Changing existing files is a separate problem. There is a script for
> that (though the data file is not public). I'm only worried with new
> files here because that's what I review and have to tell folks to
> replace their 2 pages of license text with SPDX tags. (It will be much
> easier to just tell them to run checkpatch. ;) ).
> 
> > checkpatch could, as you've done, scan for new files
> > against /dev/null, but a single patch can add
> > multiple files and each newly added file should have
> > a missing SPDX indicator check.
> 
> I was going with the easy route of just giving one warning per patch.
> I'd hope that's enough info for folks to figure out what's needed from
> there. However, it should be possible to make it per file. The main
> complication is we need to look for either '^+++' or the end of the
> patch which I didn't see an easy/clean way to do.

EOF is easy.
There already is a $realfile test for start of file.

> > My concern is that there are ~50,000 files in the
> > kernel source tree and, after that scripted patch
> > adding the tags, only about a quarter of them have
> > an SPDX tag.
> > 
> > So which files actually _need_ a SPDX tag?
> > 
> > files in -next with an SPDX tag:
> > 
> > $ git grep --name-only -i -P "spdx-licen[cs]e-identifier" | \
> >   while read file ; do basename $file ; done | \
> >   sed -r -e 's/^.*(\..*)/\1/' | \
> >   sort | uniq -c | sort -rn | head -10
> >    7514 .h
> >    3435 .c
> >    1193 Makefile
> >     486 .S
> >     221 .dts
> >     186 Kconfig
> >     185 .dtsi
> >      97 .sh
> >      34 .tc
> >      24 .debug
> > 
> > vs all files in -next (not Documentation/)
> > 
> > $ git ls-files | grep -v "^Documentation/" | \
> >   while read file ; do basename $file ; done | \
> >   sed -r -e 's/^.*(\..*)/\1/' | \
> >   sort | uniq -c | sort -rn | head -10
> >   25946 .c
> >   20360 .h
> >    2437 Makefile
> >    1454 .S
> >    1442 .dts
> >    1380 Kconfig
> >    1099 .dtsi
> >     207 .json
> >     204 .gitignore
> >     194 .sh
> >