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From: "René Scharfe" <l.s.r@web.de>
To: Jeff King <peff@peff.net>
Cc: "Git List" <git@vger.kernel.org>,
	"Martin Ågren" <martin.agren@gmail.com>,
	"Christian Couder" <christian.couder@gmail.com>,
	"Junio C Hamano" <gitster@pobox.com>
Subject: Re: [PATCH v2 5/9] bisect: avoid using the rev_info flag leak_pending
Date: Thu, 11 Jan 2018 19:57:51 +0100	[thread overview]
Message-ID: <b0fbedea-77d8-5571-6042-03b512c0680d@web.de> (raw)
In-Reply-To: <20180110080754.GE16315@sigill.intra.peff.net>

Am 10.01.2018 um 09:07 schrieb Jeff King:
> On Mon, Dec 25, 2017 at 06:45:36PM +0100, René Scharfe wrote:
> 
>> The leak_pending flag is so awkward to use that multiple comments had to
>> be added around each occurrence.  We only use it for remembering the
>> commits whose marks we have to clear after checking if all of the good
>> ones are ancestors of the bad one.  This is easy, though: We need to do
>> that for the bad and good commits, of course.
> 
> Are we sure that our list is the same as what is traversed? I won't be
> surprised if it is true, but it doesn't seem immediately obvious from
> the code:
> 
>> -static int check_ancestors(const char *prefix)
>> +static int check_ancestors(int rev_nr, struct commit **rev, const char *prefix)
>>   {
> 
> So now we take in a set of objects...
> 
>>   	struct rev_info revs;
>> -	struct object_array pending_copy;
>>   	int res;
>>   
>>   	bisect_rev_setup(&revs, prefix, "^%s", "%s", 0);
> 
> But those objects aren't provided here. bisect_rev_setup() puts its own
> set of objects into the pending list...

Yes, namely from the global variables current_bad_oid and good_revs.

>> -	/* Save pending objects, so they can be cleaned up later. */
>> -	pending_copy = revs.pending;
>> -	revs.leak_pending = 1;
>> -
>> -	/*
>> -	 * bisect_common calls prepare_revision_walk right away, which
>> -	 * (together with .leak_pending = 1) makes us the sole owner of
>> -	 * the list of pending objects.
>> -	 */
>>   	bisect_common(&revs);
>>   	res = (revs.commits != NULL);
> 
> And then we traverse, and then...
> 
>>   
>>   	/* Clean up objects used, as they will be reused. */
>> -	clear_commit_marks_for_object_array(&pending_copy, ALL_REV_FLAGS);
>> -
>> -	object_array_clear(&pending_copy);
>> +	clear_commit_marks_many(rev_nr, rev, ALL_REV_FLAGS);
> 
> ...this is the first time we look at "rev".

... which is populated by get_bad_and_good_commits() using the global
variables current_bad_oid and good_revs.

> If we already have the list of tips, could we just feed it ourselves to
> bisect_rev_setup (I think that would require us remembering which were
> "good" and "bad", but that doesn't seem like a big deal).

That's done already under the covers.  De-globalizing these variables
would make this visible.

Another way would be to store the bad and good revs in a format that
allows them to be used everywhere, thus avoiding confusing
duplication/conversions.  Commit pointers and arrays thereof should
work everywhere we currently use object_ids and oid_arrays for bad
and good revs, right?

René

  reply	other threads:[~2018-01-11 18:58 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-12-16 12:12 [PATCH] revision: introduce prepare_revision_walk_extended() René Scharfe
2017-12-17 10:20 ` Martin Ågren
2017-12-18 15:10 ` Jeff King
2017-12-18 19:18   ` René Scharfe
2017-12-19 11:49     ` Jeff King
2017-12-19 18:33       ` Junio C Hamano
2017-12-20 13:08         ` Jeff King
2017-12-21 18:41           ` René Scharfe
2017-12-24 14:22             ` Jeff King
2017-12-25 17:36               ` René Scharfe
2017-12-25 17:41 ` [PATCH v2 0/9] revision: get rid of the flag leak_pending René Scharfe
2017-12-25 17:43   ` [PATCH v2 1/9] commit: avoid allocation in clear_commit_marks_many() René Scharfe
2018-01-10  7:54     ` Jeff King
2017-12-25 17:44   ` [PATCH v2 2/9] commit: use clear_commit_marks_many() in remove_redundant() René Scharfe
2017-12-25 17:44   ` [PATCH v2 3/9] ref-filter: use clear_commit_marks_many() in do_merge_filter() René Scharfe
2017-12-25 17:44   ` [PATCH v2 4/9] object: add clear_commit_marks_all() René Scharfe
2018-01-10  7:58     ` Jeff King
2018-01-11 18:57       ` René Scharfe
2018-01-12 15:20         ` Jeff King
2017-12-25 17:45   ` [PATCH v2 5/9] bisect: avoid using the rev_info flag leak_pending René Scharfe
2018-01-10  8:07     ` Jeff King
2018-01-11 18:57       ` René Scharfe [this message]
2018-01-12 15:23         ` Jeff King
2017-12-25 17:46   ` [PATCH v2 6/9] bundle: " René Scharfe
2017-12-28 21:13     ` Junio C Hamano
2018-01-10  8:18     ` Jeff King
2017-12-25 17:47   ` [PATCH v2 7/9] checkout: " René Scharfe
2017-12-28 21:24     ` Junio C Hamano
2017-12-25 17:47   ` [PATCH v2 8/9] revision: remove the unused " René Scharfe
2017-12-25 17:48   ` [PATCH v2 9/9] commit: remove unused function clear_commit_marks_for_object_array() René Scharfe
2017-12-28 20:32   ` [PATCH v2 0/9] revision: get rid of the flag leak_pending Junio C Hamano
2018-01-10  8:20   ` Jeff King

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