Re: [RFC PATCH 0/3] rebase-interactive

[Wink Saville <wink@saville.com>]

On Tue, Mar 20, 2018 at 2:11 PM, Eric Sunshine <sunshine@sunshineco.com> wrote:
> On Tue, Mar 20, 2018 at 4:45 PM, Wink Saville <wink@saville.com> wrote:
>> Patch 0001 creates a library of functions which can be
>> used by git-rebase--interactive and
>> git-rebase--interactive--preserve-merges. The functions are
>> those that exist in git-rebase--interactive.sh plus new
>> functions created from the body of git_rebase_interactive
>> that will be used git_rebase_interactive in the third patch
>> and git_rebase_interactive_preserve_merges in the second
>> patch. None of the functions are invoked so there is no
>> logic changes and the system builds and passes all tests
>> on travis-ci.org.
>>
>> Patch 0002 creates git-rebase--interactive--preserve-merges.sh
>> with the function git_rebase_interactive_preserve_merges. The contents
>> of the function are refactored from git_rebase_interactive and
>> uses existing and new functions in the library. A small modification
>> of git-rebase is also done to invoke the new function when the -p
>> switch is used with git-rebase. When this is applied on top of
>> 0001 the system builds and passes all tests on travis-ci.org.
>>
>> The final patch, 0003, removes all unused code from
>> git_rebase_interactive and uses the functions from the library
>> where appropriate. And, of course, when applied on top of 0002
>> the system builds and passes all tests on travis-ci.org.
>
> A problem with this approach is that it loses "blame" information. A
> git-blame of git-rebase--interactive--lib.sh shows all code in that
> file as having arisen spontaneously from thin air; it is unable to
> trace its real history. It would be much better to actually _move_
> code to the new file (and update callers if necessary), which would
> preserve provenance.
>
> Ideally, patches which move code around should do so verbatim (or at
> least as close to verbatim as possible) to ease review burden.
> Sometimes changes to code are needed to make it relocatable before
> movement, in which case those changes should be made as separate
> preparatory patches, again to ease review.
>
> As it is, without detailed spelunking, it is not immediately clear to
> a reviewer which functions in git-rebase--interactive--lib.sh are
> newly written, and which are merely moved (or moved and edited) from
> git-rebase--interactive.sh. This shortcoming suggests that the patch
> series could be re-worked to do the refactoring in a more piecemeal
> fashion which more clearly holds the hands of those trying to
> understand the changes. (For instance, one or more preparatory patches
> may be needed to make the code relocatable, followed by verbatim code
> relocation, possibly iterating these steps if some changes depend upon
> earlier changes, etc.)
>
> Thanks.

Must all intermediate commits continue build and pass tests?