[RFC PATCH 0/4] pathspec labels [WAS: submodule groups]

[Stefan Beller <sbeller@google.com>]

After some fruitful discussion[1] in which Junio suggested trying a very
different route[2] that is more general and not submodule related, I considered
doing a mock for this.

This lets you label arbitrary pathspecs, e.g. in git.git we may want to have:

    t/t[0-9]*.sh label=tests
    
such that

    $ git log --author=Beller ":(label=tests)"
    
would show all commits in which I touched tests.

This has suprisingly few lines of code, as the first 3 patches are refactoring.
The actual new feature is in the last patch.

This would solve the submodule issues I want to solve, as I can produce a
.gitattributes like:

    ./submodule1 label=default
    ./submodule2 label=default
    ./submodule3 label=optional-feature1
    
and then I'd instruct the users to clone like this:

    git clone .. superproject
    cd superproject
    git submodule update --init :(label:default)
    
The second part of the submodule series to collapse these three commands
will come as an extra series later, then.

What annoys me here:
Attributes can only be set once at the moment, there is no way to collect all
attributes. If we'd have such a collection feature we would be able to
configure this:

    *.[ch] label=C,code
    contrib/** label=oldstuff
    
and run this:

    git status ":(label:C oldstuff)"
    
which would be the equivalent to

    contrib/**.[ch]
    
as in this proposed implementation the labels which are given within one
pathspec item are logical AND. To get the logical OR, you'd have to give multiple
pathspec items, i.e. ":(label:C)" ":(label:oldstuff)"

Feedback welcome!

Thanks,
Stefan

[1] http://thread.gmane.org/gmane.comp.version-control.git/294212
[2] http://thread.gmane.org/gmane.comp.version-control.git/294212/focus=294391

Stefan Beller (4):
  Documentation: correct typo in example for querying attributes
  pathspec: move long magic parsing out of prefix_pathspec
  pathspec: move prefix check out of the inner loop
  pathspec: record labels

 Documentation/glossary-content.txt            |   5 ++
 Documentation/technical/api-gitattributes.txt |   2 +-
 attr.h                                        |   1 +
 dir.c                                         |  31 ++++++++
 pathspec.c                                    | 109 +++++++++++++++++---------
 pathspec.h                                    |   1 +
 t/t6134-pathspec-with-labels.sh               |  91 +++++++++++++++++++++
 7 files changed, 201 insertions(+), 39 deletions(-)
 create mode 100755 t/t6134-pathspec-with-labels.sh

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2.8.2.400.g66c4903.dirty