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From: Alban Gruin <alban.gruin@gmail.com>
To: Junio C Hamano <gitster@pobox.com>
Cc: git@vger.kernel.org, phillip.wood@dunelm.org.uk
Subject: Re: [PATCH v3 05/11] merge-resolve: rewrite in C
Date: Fri, 6 Nov 2020 20:53:18 +0100	[thread overview]
Message-ID: <f321f01d-8071-9be3-7214-f8506081f17c@gmail.com> (raw)
In-Reply-To: <xmqqr1pyashe.fsf@gitster.c.googlers.com>

Le 16/10/2020 à 21:19, Junio C Hamano a écrit :
> Alban Gruin <alban.gruin@gmail.com> writes:
> 
>> +#include "cache.h"
>> +#include "builtin.h"
>> +#include "merge-strategies.h"
>> +
>> +static const char builtin_merge_resolve_usage[] =
>> +	"git merge-resolve <bases>... -- <head> <remote>";
>> +
>> +int cmd_merge_resolve(int argc, const char **argv, const char *prefix)
>> +{
>> +	int i, is_baseless = 1, sep_seen = 0;
>> +	const char *head = NULL;
>> +	struct commit_list *bases = NULL, *remote = NULL;
>> +	struct commit_list **next_base = &bases;
>> +
>> +	if (argc < 5)
>> +		usage(builtin_merge_resolve_usage);
>> +
>> +	setup_work_tree();
>> +	if (repo_read_index(the_repository) < 0)
>> +		die("invalid index");
>> +
>> +	/* The first parameters up to -- are merge bases; the rest are
>> +	 * heads. */
> 
> Style (I won't repeat).
> 
>> +	for (i = 1; i < argc; i++) {
>> +		if (strcmp(argv[i], "--") == 0)
> 
> 	if (!strcmp(...))
> 
> is more typical than comparing with "== 0".
> 
>> +			sep_seen = 1;
>> +		else if (strcmp(argv[i], "-h") == 0)
>> +			usage(builtin_merge_resolve_usage);
>> +		else if (sep_seen && !head)
>> +			head = argv[i];
>> +		else if (remote) {
>> +			/* Give up if we are given two or more remotes.
>> +			 * Not handling octopus. */
>> +			return 2;
>> +		} else {
>> +			struct object_id oid;
>> +
>> +			get_oid(argv[i], &oid);
>> +			is_baseless &= sep_seen;
>> +
>> +			if (!oideq(&oid, the_hash_algo->empty_tree)) {
> 
> What is this business about an empty tree about?
> 

I don’t remember my intent here -- perhaps I wanted to avoid merges on
empty trees…  I’ll remove that from here and merge-octopus.c.

>> +				struct commit *commit;
>> +				commit = lookup_commit_or_die(&oid, argv[i]);
>> +
>> +				if (sep_seen)
>> +					commit_list_append(commit, &remote);
>> +				else
>> +					next_base = commit_list_append(commit, next_base);
>> +			}
>> +		}
>> +	}
>> +
>> +	/* Give up if this is a baseless merge. */
>> +	if (is_baseless)
>> +		return 2;
> 
> This is quite convoluted.  
> 
> The original is much more straight-forward.  We just said "grab
> everything before we see '--' and call them bases; immediately after
> '--' is HEAD and everything else is remote.  Now do we have any
> base?  Otherwise we cannot handle it".
> 
> I cannot see an equivalence to it in the rewritten result, with the
> bit operation with is_baseless and sep_seen.  Wouldn't it be the
> matter of checking if next_base is NULL, or is there something more
> subtle that deserves in-code comment going on?
> 

After re-reading this many, many weeks later, I can confirm that this is
convoluted, and that there is a much better way to perform some checks…
 for instance, checking if `bases' is NULL instead of having
`is_baseless', or checking after the loop if `remotes->next' is not NULL
to verify if there is multiple remotes.

> Thanks.
> 

Alban


  reply	other threads:[~2020-11-06 19:53 UTC|newest]

Thread overview: 183+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-25 12:19 [RFC PATCH v1 00/17] Rewrite the remaining merge strategies from shell to C Alban Gruin
2020-06-25 12:19 ` [RFC PATCH v1 01/17] t6027: modernise tests Alban Gruin
2020-06-25 12:19 ` [RFC PATCH v1 02/17] merge-one-file: rewrite in C Alban Gruin
2020-06-25 14:55   ` Chris Torek
2020-06-25 15:16   ` Phillip Wood
2020-06-25 18:17     ` Phillip Wood
2020-06-26 14:33       ` Phillip Wood
2020-07-12 11:22     ` Alban Gruin
2020-06-25 12:19 ` [RFC PATCH v1 03/17] merge-one-file: remove calls to external processes Alban Gruin
2020-06-25 12:19 ` [RFC PATCH v1 04/17] merge-one-file: use error() instead of fprintf(stderr, ...) Alban Gruin
2020-06-25 12:19 ` [RFC PATCH v1 05/17] merge-one-file: libify merge_one_file() Alban Gruin
2020-06-25 12:19 ` [RFC PATCH v1 06/17] merge-index: libify merge_one_path() and merge_all() Alban Gruin
2020-06-26 10:13   ` Phillip Wood
2020-06-26 14:32     ` Phillip Wood
2020-07-12 11:36     ` Alban Gruin
2020-07-12 18:02       ` Phillip Wood
2020-07-12 20:10         ` Alban Gruin
2020-06-25 12:19 ` [RFC PATCH v1 07/17] merge-resolve: rewrite in C Alban Gruin
2020-06-25 12:19 ` [RFC PATCH v1 08/17] merge-resolve: remove calls to external processes Alban Gruin
2020-06-25 12:19 ` [RFC PATCH v1 09/17] merge-resolve: libify merge_resolve() Alban Gruin
2020-06-25 12:19 ` [RFC PATCH v1 10/17] merge-recursive: move better_branch_name() to merge.c Alban Gruin
2020-06-25 12:19 ` [RFC PATCH v1 11/17] merge-octopus: rewrite in C Alban Gruin
2020-06-25 12:19 ` [RFC PATCH v1 12/17] merge-octopus: remove calls to external processes Alban Gruin
2020-06-25 12:19 ` [RFC PATCH v1 13/17] merge-octopus: libify merge_octopus() Alban Gruin
2020-06-25 12:19 ` [RFC PATCH v1 14/17] merge: use the "resolve" strategy without forking Alban Gruin
2020-06-25 12:19 ` [RFC PATCH v1 15/17] merge: use the "octopus" " Alban Gruin
2020-06-25 12:19 ` [RFC PATCH v1 16/17] sequencer: use the "resolve" " Alban Gruin
2020-06-25 16:11   ` Phillip Wood
2020-07-12 11:27     ` Alban Gruin
2020-06-25 12:19 ` [RFC PATCH v1 17/17] sequencer: use the "octopus" merge " Alban Gruin
2020-09-01 10:56 ` [PATCH v2 00/11] Rewrite the remaining merge strategies from shell to C Alban Gruin
2020-09-01 10:56   ` [PATCH v2 01/11] t6027: modernise tests Alban Gruin
2020-09-01 10:56   ` [PATCH v2 02/11] merge-one-file: rewrite in C Alban Gruin
2020-09-01 21:06     ` Junio C Hamano
2020-09-02 14:50       ` Alban Gruin
2020-09-01 10:56   ` [PATCH v2 03/11] merge-index: libify merge_one_path() and merge_all() Alban Gruin
2020-09-01 21:11     ` Junio C Hamano
2020-09-02 15:37       ` Alban Gruin
2020-09-01 10:56   ` [PATCH v2 04/11] merge-index: don't fork if the requested program is `git-merge-one-file' Alban Gruin
2020-09-01 10:56   ` [PATCH v2 05/11] merge-resolve: rewrite in C Alban Gruin
2020-09-01 10:57   ` [PATCH v2 06/11] merge-recursive: move better_branch_name() to merge.c Alban Gruin
2020-09-01 10:57   ` [PATCH v2 07/11] merge-octopus: rewrite in C Alban Gruin
2020-09-01 10:57   ` [PATCH v2 08/11] merge: use the "resolve" strategy without forking Alban Gruin
2020-09-01 10:57   ` [PATCH v2 09/11] merge: use the "octopus" " Alban Gruin
2020-09-01 10:57   ` [PATCH v2 10/11] sequencer: use the "resolve" " Alban Gruin
2020-09-01 10:57   ` [PATCH v2 11/11] sequencer: use the "octopus" merge " Alban Gruin
2020-10-05 12:26   ` [PATCH v3 00/11] Rewrite the remaining merge strategies from shell to C Alban Gruin
2020-10-05 12:26     ` [PATCH v3 01/11] t6027: modernise tests Alban Gruin
2020-10-06 20:50       ` Junio C Hamano
2020-10-05 12:26     ` [PATCH v3 02/11] merge-one-file: rewrite in C Alban Gruin
2020-10-06 22:01       ` Junio C Hamano
2020-10-21 19:47         ` Alban Gruin
2020-10-21 20:28           ` Junio C Hamano
2020-10-21 21:20             ` Junio C Hamano
2020-10-21 20:30           ` Junio C Hamano
2020-10-05 12:26     ` [PATCH v3 03/11] merge-index: libify merge_one_path() and merge_all() Alban Gruin
2020-10-09  4:48       ` Junio C Hamano
2020-11-06 19:53         ` Alban Gruin
2020-10-05 12:26     ` [PATCH v3 04/11] merge-index: don't fork if the requested program is `git-merge-one-file' Alban Gruin
2020-10-16 19:07       ` Junio C Hamano
2020-10-05 12:26     ` [PATCH v3 05/11] merge-resolve: rewrite in C Alban Gruin
2020-10-16 19:19       ` Junio C Hamano
2020-11-06 19:53         ` Alban Gruin [this message]
2020-10-05 12:26     ` [PATCH v3 06/11] merge-recursive: move better_branch_name() to merge.c Alban Gruin
2020-10-05 12:26     ` [PATCH v3 07/11] merge-octopus: rewrite in C Alban Gruin
2020-10-05 12:26     ` [PATCH v3 08/11] merge: use the "resolve" strategy without forking Alban Gruin
2020-10-05 12:26     ` [PATCH v3 09/11] merge: use the "octopus" " Alban Gruin
2020-10-05 12:26     ` [PATCH v3 10/11] sequencer: use the "resolve" " Alban Gruin
2020-10-05 12:26     ` [PATCH v3 11/11] sequencer: use the "octopus" merge " Alban Gruin
2020-10-07  6:57     ` [PATCH v3 00/11] Rewrite the remaining merge strategies from shell to C Johannes Schindelin
2020-11-13 11:04     ` [PATCH v4 00/12] " Alban Gruin
2020-11-13 11:04       ` [PATCH v4 01/12] t6027: modernise tests Alban Gruin
2020-11-13 11:04       ` [PATCH v4 02/12] update-index: move add_cacheinfo() to read-cache.c Alban Gruin
2020-11-13 11:04       ` [PATCH v4 03/12] merge-one-file: rewrite in C Alban Gruin
2020-11-13 11:04       ` [PATCH v4 04/12] merge-index: libify merge_one_path() and merge_all() Alban Gruin
2020-11-13 11:04       ` [PATCH v4 05/12] merge-index: don't fork if the requested program is `git-merge-one-file' Alban Gruin
2020-11-13 11:04       ` [PATCH v4 06/12] merge-resolve: rewrite in C Alban Gruin
2020-11-13 11:04       ` [PATCH v4 07/12] merge-recursive: move better_branch_name() to merge.c Alban Gruin
2020-11-13 11:04       ` [PATCH v4 08/12] merge-octopus: rewrite in C Alban Gruin
2020-11-13 11:04       ` [PATCH v4 09/12] merge: use the "resolve" strategy without forking Alban Gruin
2020-11-13 11:04       ` [PATCH v4 10/12] merge: use the "octopus" " Alban Gruin
2020-11-13 11:04       ` [PATCH v4 11/12] sequencer: use the "resolve" " Alban Gruin
2020-11-13 11:04       ` [PATCH v4 12/12] sequencer: use the "octopus" merge " Alban Gruin
2020-11-16 10:21       ` [PATCH v5 00/12] Rewrite the remaining merge strategies from shell to C Alban Gruin
2020-11-16 10:21         ` [PATCH v5 01/12] t6027: modernise tests Alban Gruin
2020-11-16 10:21         ` [PATCH v5 02/12] update-index: move add_cacheinfo() to read-cache.c Alban Gruin
2020-11-16 10:21         ` [PATCH v5 03/12] merge-one-file: rewrite in C Alban Gruin
2020-11-16 10:21         ` [PATCH v5 04/12] merge-index: libify merge_one_path() and merge_all() Alban Gruin
2020-11-16 10:21         ` [PATCH v5 05/12] merge-index: don't fork if the requested program is `git-merge-one-file' Alban Gruin
2020-11-16 10:21         ` [PATCH v5 06/12] merge-resolve: rewrite in C Alban Gruin
2020-11-16 10:21         ` [PATCH v5 07/12] merge-recursive: move better_branch_name() to merge.c Alban Gruin
2020-11-16 10:21         ` [PATCH v5 08/12] merge-octopus: rewrite in C Alban Gruin
2020-11-16 10:21         ` [PATCH v5 09/12] merge: use the "resolve" strategy without forking Alban Gruin
2020-11-16 10:21         ` [PATCH v5 10/12] merge: use the "octopus" " Alban Gruin
2020-11-16 10:21         ` [PATCH v5 11/12] sequencer: use the "resolve" " Alban Gruin
2020-11-16 10:21         ` [PATCH v5 12/12] sequencer: use the "octopus" merge " Alban Gruin
2020-11-24 11:53         ` [PATCH v6 00/13] Rewrite the remaining merge strategies from shell to C Alban Gruin
2020-11-24 11:53           ` [PATCH v6 01/13] t6407: modernise tests Alban Gruin
2020-11-24 11:53           ` [PATCH v6 02/13] t6060: modify multiple files to expose a possible issue with merge-index Alban Gruin
2020-11-24 11:53           ` [PATCH v6 03/13] update-index: move add_cacheinfo() to read-cache.c Alban Gruin
2020-12-22 20:54             ` Junio C Hamano
2020-11-24 11:53           ` [PATCH v6 04/13] merge-one-file: rewrite in C Alban Gruin
2020-12-22 21:36             ` Junio C Hamano
2021-01-03 22:41               ` Alban Gruin
2021-01-08  6:54                 ` Junio C Hamano
2020-11-24 11:53           ` [PATCH v6 05/13] merge-index: libify merge_one_path() and merge_all() Alban Gruin
2021-01-05 15:59             ` Derrick Stolee
2021-01-05 23:20               ` Alban Gruin
2020-11-24 11:53           ` [PATCH v6 06/13] merge-index: don't fork if the requested program is `git-merge-one-file' Alban Gruin
2021-01-05 16:11             ` Derrick Stolee
2021-01-05 17:35               ` Martin Ågren
2021-01-05 23:20                 ` Alban Gruin
2021-01-05 23:20               ` Alban Gruin
2021-01-06  2:04                 ` Junio C Hamano
2021-01-10 17:15                   ` Alban Gruin
2021-01-10 20:51                     ` Junio C Hamano
2021-03-08 20:32                       ` Alban Gruin
2020-11-24 11:53           ` [PATCH v6 07/13] merge-resolve: rewrite in C Alban Gruin
2020-11-24 11:53           ` [PATCH v6 08/13] merge-recursive: move better_branch_name() to merge.c Alban Gruin
2021-01-05 16:19             ` Derrick Stolee
2020-11-24 11:53           ` [PATCH v6 09/13] merge-octopus: rewrite in C Alban Gruin
2021-01-05 16:40             ` Derrick Stolee
2020-11-24 11:53           ` [PATCH v6 10/13] merge: use the "resolve" strategy without forking Alban Gruin
2021-01-05 16:45             ` Derrick Stolee
2020-11-24 11:53           ` [PATCH v6 11/13] merge: use the "octopus" " Alban Gruin
2020-11-24 11:53           ` [PATCH v6 12/13] sequencer: use the "resolve" " Alban Gruin
2020-11-24 11:53           ` [PATCH v6 13/13] sequencer: use the "octopus" merge " Alban Gruin
2020-11-24 19:34           ` [PATCH v6 00/13] Rewrite the remaining merge strategies from shell to C SZEDER Gábor
2021-01-05 16:50           ` Derrick Stolee
2021-03-17 20:49           ` [PATCH v7 00/15] " Alban Gruin
2021-03-17 20:49             ` [PATCH v7 01/15] t6407: modernise tests Alban Gruin
2021-03-17 20:49             ` [PATCH v7 02/15] t6060: modify multiple files to expose a possible issue with merge-index Alban Gruin
2021-03-17 20:49             ` [PATCH v7 03/15] t6060: add tests for removed files Alban Gruin
2021-03-22 21:36               ` Johannes Schindelin
2021-03-23 20:43                 ` Alban Gruin
2021-03-17 20:49             ` [PATCH v7 04/15] merge-index: libify merge_one_path() and merge_all() Alban Gruin
2021-03-17 20:49             ` [PATCH v7 05/15] merge-index: drop the index Alban Gruin
2021-03-17 20:49             ` [PATCH v7 06/15] merge-index: add a new way to invoke `git-merge-one-file' Alban Gruin
2021-03-17 20:49             ` [PATCH v7 07/15] update-index: move add_cacheinfo() to read-cache.c Alban Gruin
2021-03-22 21:59               ` Johannes Schindelin
2021-03-23 20:45                 ` Alban Gruin
2021-03-17 20:49             ` [PATCH v7 08/15] merge-one-file: rewrite in C Alban Gruin
2021-03-22 22:20               ` Johannes Schindelin
2021-03-23 20:53                 ` Alban Gruin
2021-03-24  9:10                   ` Johannes Schindelin
2021-04-10 14:17                     ` Alban Gruin
2021-03-17 20:49             ` [PATCH v7 09/15] merge-resolve: " Alban Gruin
2021-03-23 22:21               ` Johannes Schindelin
2021-04-10 14:17                 ` Alban Gruin
2021-03-17 20:49             ` [PATCH v7 10/15] merge-recursive: move better_branch_name() to merge.c Alban Gruin
2021-03-17 20:49             ` [PATCH v7 11/15] merge-octopus: rewrite in C Alban Gruin
2021-03-23 23:58               ` Johannes Schindelin
2021-03-17 20:49             ` [PATCH v7 12/15] merge: use the "resolve" strategy without forking Alban Gruin
2021-03-17 20:49             ` [PATCH v7 13/15] merge: use the "octopus" " Alban Gruin
2021-03-17 20:49             ` [PATCH v7 14/15] sequencer: use the "resolve" " Alban Gruin
2021-03-17 20:49             ` [PATCH v7 15/15] sequencer: use the "octopus" merge " Alban Gruin
2022-08-09 18:54             ` [PATCH v8 00/14] Rewrite the remaining merge strategies from shell to C Alban Gruin
2022-08-09 18:54               ` [PATCH v8 01/14] t6060: modify multiple files to expose a possible issue with merge-index Alban Gruin
2022-08-09 18:54               ` [PATCH v8 02/14] t6060: add tests for removed files Alban Gruin
2022-08-09 18:54               ` [PATCH v8 03/14] merge-index: libify merge_one_path() and merge_all() Alban Gruin
2022-08-17  2:10                 ` Ævar Arnfjörð Bjarmason
2022-08-09 18:54               ` [PATCH v8 04/14] merge-index: drop the index Alban Gruin
2022-08-09 18:54               ` [PATCH v8 05/14] merge-index: add a new way to invoke `git-merge-one-file' Alban Gruin
2022-08-09 21:36                 ` Johannes Schindelin
2022-08-10 13:14                   ` Phillip Wood
2022-08-09 18:54               ` [PATCH v8 06/14] update-index: move add_cacheinfo() to read-cache.c Alban Gruin
2022-08-09 18:54               ` [PATCH v8 07/14] merge-one-file: rewrite in C Alban Gruin
2022-08-09 22:01                 ` Johannes Schindelin
2022-08-09 18:54               ` [PATCH v8 08/14] merge-resolve: " Alban Gruin
2022-08-10 15:03                 ` Phillip Wood
2022-08-10 21:20                   ` Junio C Hamano
2022-08-16 12:09                     ` Johannes Schindelin
2022-08-16 19:36                       ` Junio C Hamano
2022-08-16 12:17                   ` Johannes Schindelin
2022-08-16 14:02                     ` Phillip Wood
2022-08-17  2:16                 ` Ævar Arnfjörð Bjarmason
2022-08-09 18:54               ` [PATCH v8 09/14] merge-recursive: move better_branch_name() to merge.c Alban Gruin
2022-08-09 18:54               ` [PATCH v8 10/14] merge-octopus: rewrite in C Alban Gruin
2022-08-09 18:54               ` [PATCH v8 11/14] merge: use the "resolve" strategy without forking Alban Gruin
2022-08-13 16:18                 ` Junio C Hamano
2022-08-09 18:54               ` [PATCH v8 12/14] merge: use the "octopus" " Alban Gruin
2022-08-09 18:54               ` [PATCH v8 13/14] sequencer: use the "resolve" " Alban Gruin
2022-08-09 18:54               ` [PATCH v8 14/14] sequencer: use the "octopus" " Alban Gruin

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