Re: The merge from hell...

From: Junio C Hamano <junkio@cox.net>
Date: Feb 4, 2006, 02:35 UTC
Message-ID: <7vy80r97h6.fsf@assigned-by-dhcp.cox.net>
In-Reply-To: <F7DC2337C7631D4386A2DF6E8FB22B3005F34393@hdsmsx401.amr.corp.intel.com>

"Brown, Len" <len.brown@intel.com> writes:

Show 7 quoted lines

> Naming the branch is just eye-candy for the merge comment.
> My topic branch labels in refs/my-branch never get to kernel.org, so you're
> not going to see the pretty green tags on topic branches branches that I see.
>
> I include the full-URL of the bug report in the original commit comments
> for those who are interested.  I think this it the important place to put it,
> and in practice I've found it to be extremely useful.

Both excellent points.

If I may digress,...

It appears most of the topic branches in that merge have only one commit since they forked from trunk (the development track led to the first parent of that merge), but some seem to have more than one commits.

It might make sense if we have a tool support to pre-format the merge messages like this, given set of branch names:

    [ACPI] Merge 3549, 4320, 4485, 4588, 4980, 5483, 5651, acpica, asus, fops and pnpacpi branches into release

    3549: [ACPI] Disable C2/C3 for _all_ IBM R40e Laptops
    4320: [ACPI] fix reboot upon suspend-to-disk
    4485: [ACPI] handle BIOS with implicit C1 in _CST
    4588: [ACPI] fix acpi_os_wait_sempahore() finite timeout case (AE_TIME warning)
    4980 (5 commits): [ACPI] build EC driver on IA64
    5483 (3 commits): [ACPI] fix acpi_cpufreq.c build warrning
    5651: [ACPI] SMP S3 resume: evaluate _WAK after INIT
    acpica (23 commits): [ACPI] ACPICA 20060113
    asus (3 commits): [ACPI_ASUS] fix asus module param description
    fops (2 commits): [ACPI] make two processor functions static
    pnpacpi (3 commits): [PNPACPI] clean excluded_id_list[]

Here I am counting the number of commits on each topic since it last diverged from trunk (`merge-base release branch`), and showing the latest commit of the topic.

We could even go further and have "per branch annotation" that lets you do something like this:

	$ git checkout -b 3549 \
          --description 'http://bugzilla.kernel.org/show_bug.cgi?id=3549'
	$ work work
        $ git commit
	... work on other topics in similar way ...
        ... later, on the 'release' branch ...
        $ git pull . 3549 4320 4485...

With that, we could give a default merge message formatted like this:

    Merge 3549, 4320, 4485, 4588, 4980, 5483, 5651, acpica, asus, fops and pnpacpi branches into release

    3549: http://bugzilla.kernel.org/show_bug.cgi?id=3549
     [ACPI] Disable C2/C3 for _all_ IBM R40e Laptops

    4320: http://bugzilla.kernel.org/show_bug.cgi?id=4320
     [ACPI] fix reboot upon suspend-to-disk

    5483: http://bugzilla.kernel.org/show_bug.cgi?id=5483
     [ACPI] fix acpi_cpufreq.c build warrning
     [ACPI] IA64 ZX1 buildfix for _PDC patch
     [ACPI] Avoid BIOS inflicted crashes by evaluating _PDC only once

    pnpacpi: work on PNP-ACPI issues
     [PNPACPI] clean excluded_id_list[]
     [PNPACPI] Ignore devices that have no resources
     [ACPI] enable PNPACPI support for resource types used by HP serial ports

This last digression might be too much, though. It may be something that is better computed by 'git log' while reviewing history, except that the description of each branch cannot be given that way.