Re: Splitting a rev list into 2 sets

Francis Moreau [off-list ref] writes:

On Thu, Jun 20, 2013 at 3:20 PM, Thomas Rast [off-list ref] wrote:

quoted

  positive=$(git rev-parse "$@" | grep -v '^\^')
  negative=$(git rev-parse "$@" | grep '^\^')
  boundary=$(git rev-list --boundary $positive ^master | sed -n 's/^-//p')
  # the intersection is
  git rev-list $boundary $negative

I think there's a minor issue here, when boundary is empty. Please
correct me if I'm wrong but I think it can only happen if positive is
simply master or a subset of master. In that case I think the solution
is just make boundary equal to positive:

     # the intersection is
     git rev-list ${boundary:-$positive} $negative

Now I'm going to see if that solution is faster than the initial one.

Jan "jast" Krüger pointed out on #git that

  git log $(git merge-base --all A B)

is exactly the set of commits reachable from both A and B; so there's
your intersection operator :-)

So it would seem that a much simpler approach is

  git rev-list $(git merge-base --all master $positive) --not $negative

avoiding the boundary handling and special-case.  It relies on the
(weird?) property that $(git merge-base --all A B1 B2 ...) shows the
merge bases of A with a hypothetical merge of B1, B2, ..., which is just
what you need here.

-- 
Thomas Rast
trast@{inf,student}.ethz.ch

Hello Thomas,

On Mon, Jun 24, 2013 at 11:59 AM, Thomas Rast [off-list ref] wrote:

Francis Moreau [off-list ref] writes:

quoted

On Thu, Jun 20, 2013 at 3:20 PM, Thomas Rast [off-list ref] wrote:

quoted

  positive=$(git rev-parse "$@" | grep -v '^\^')
  negative=$(git rev-parse "$@" | grep '^\^')
  boundary=$(git rev-list --boundary $positive ^master | sed -n 's/^-//p')
  # the intersection is
  git rev-list $boundary $negative

I think there's a minor issue here, when boundary is empty. Please
correct me if I'm wrong but I think it can only happen if positive is
simply master or a subset of master. In that case I think the solution
is just make boundary equal to positive:

     # the intersection is
     git rev-list ${boundary:-$positive} $negative

Now I'm going to see if that solution is faster than the initial one.

Jan "jast" Krüger pointed out on #git that

  git log $(git merge-base --all A B)

is exactly the set of commits reachable from both A and B; so there's
your intersection operator :-)

nice :)

So it would seem that a much simpler approach is

  git rev-list $(git merge-base --all master $positive) --not $negative

avoiding the boundary handling and special-case.  It relies on the
(weird?) property that $(git merge-base --all A B1 B2 ...) shows the
merge bases of A with a hypothetical merge of B1, B2, ..., which is just
what you need here.

Thank you Thomas, that's exactly what I was asking for :)

--
Francis