[PATCHv12 01/10] receive-pack.c: shorten the execute_commands loop over all commands

Make the main "execute_commands" loop in receive-pack easier to read by splitting out some steps into helper functions. The new helper 'should_process_cmd' checks if a ref update is unnecessary, whether due to an error having occurred or for another reason. The helper 'warn_if_skipped_connectivity_check' warns if we have forgotten to run a connectivity check on a ref which is shallow for the client which would be a bug.

This will help us to duplicate less code in a later patch when we make a second copy of the "execute_commands" loop.

No functional change intended.

Signed-off-by: Stefan Beller <sbeller@google.com>
---

Notes:
    v12:
    * no changes
    v11:
    * rename assure_connectivity_checked to warn_if_skipped_connectivity_check
    
    >> This is why I choose the word assure.
    >If this patch depends on the next one, would it make sense to put them
    >in the opposite order?
    
    With the next patch applied which dies if the assumption doesn't hold,
    assure/assume sounds to me as if it describes the siuation well.
    
    > My personal preference would be to refactor the preceding code to make
    > the check unnecessary.
    
    The way I understand it, the shallow case is spread out all over the place
    not by choise but because it doesn't work better. So the original author
    (Duy) was wise enough to put checks in place because knowing it is fragile
    and may break in the future?
    This series doesn't intend to refactor the shallow case.
    
    So I picked up warn_if_skipped_connectivity_check as I'm ok with that.
    
    v10:
    * rename check_shallow_bugs to assure_connectivity_checked.
    * reword commit message.
    
    v9:
    * simplified should_process_cmd to be a one liner
    * check_shallow_bugs doesn't check of shallow_update being set, rather
      the function is just called if that option is set.
    
    v8: no change
    
    v7:
     new in v7 as in v7 I'd split up the previous
     [PATCH 4/7] receive-pack.c: receive-pack.c: use a single ref_transaction for atomic pushes
     as suggested by Eric.
    
     This is pretty much
    > patch 1: Factor out code into helper functions which will be needed by
    > the upcoming atomic and non-atomic worker functions. Example helpers:
    > 'cmd->error_string' and cmd->skip_update' check; and the
    > 'si->shallow_ref[cmd->index]' check and handling.

 builtin/receive-pack.c | 43 +++++++++++++++++++++++++++----------------
 1 file changed, 27 insertions(+), 16 deletions(-)