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From: Derrick Stolee <stolee@gmail.com>
To: Elijah Newren via GitGitGadget <gitgitgadget@gmail.com>,
	git@vger.kernel.org
Cc: Derrick Stolee <dstolee@microsoft.com>,
	Jonathan Tan <jonathantanmy@google.com>,
	Taylor Blau <me@ttaylorr.com>, Elijah Newren <newren@gmail.com>
Subject: Re: [PATCH v2 12/13] merge-ort: handle interactions of caching and rename/rename(1to1) cases
Date: Mon, 17 May 2021 10:16:13 -0400	[thread overview]
Message-ID: <0794d786-352f-33cb-19c4-0b4671ab51b7@gmail.com> (raw)
In-Reply-To: <28b622a8261b8bf9190ecc9ce4189334ca553109.1620094339.git.gitgitgadget@gmail.com>

On 5/3/21 10:12 PM, Elijah Newren via GitGitGadget wrote:
> From: Elijah Newren <newren@gmail.com>
> 
> As documented in Documentation/technical/remembering-renames.txt, and as
> tested for in the two testcases in t6429 with "rename same file
> identically" in their description, there is one case where we need to
> have renames in one commit NOT be cached for the next commit in our
> rebase sequence -- namely, rename/rename(1to1) cases.  Rather than
> specifically trying to uncache those and fix up dir_rename_counts() to
> match (which would also be valid but more work), we simply disable the
> optimization when this really rare type of rename occurs.
> 
> Signed-off-by: Elijah Newren <newren@gmail.com>
> ---
>  merge-ort.c | 30 +++++++++++++++++++++++++++++-
>  1 file changed, 29 insertions(+), 1 deletion(-)
> 
> diff --git a/merge-ort.c b/merge-ort.c
> index 741970cd05e7..2fc98b803d1c 100644
> --- a/merge-ort.c
> +++ b/merge-ort.c
> @@ -2100,6 +2100,9 @@ static int process_renames(struct merge_options *opt,
>  			VERIFY_CI(side2);
>  
>  			if (!strcmp(pathnames[1], pathnames[2])) {
> +				struct rename_info *ri = &opt->priv->renames;
> +				int j;
> +
>  				/* Both sides renamed the same way */
>  				assert(side1 == side2);
>  				memcpy(&side1->stages[0], &base->stages[0],
> @@ -2109,6 +2112,16 @@ static int process_renames(struct merge_options *opt,
>  				base->merged.is_null = 1;
>  				base->merged.clean = 1;
>  
> +				/*
> +				 * Disable remembering renames optimization;
> +				 * rename/rename(1to1) is incredibly rare, and
> +				 * just disabling the optimization is easier
> +				 * than purging cached_pairs,
> +				 * cached_target_names, and dir_rename_counts.
> +				 */
> +				for (j = 0; j < 3; j++)
> +					ri->merge_trees[j] = NULL;
> +

nit: it might be helpful to initialize ri closer to when it will
be used, just to have the value of 'ri' be easier to find when
looking at this loop.

> @@ -3896,7 +3909,22 @@ static void merge_check_renames_reusable(struct merge_options *opt,
>  
>  	renames = &opti->renames;
>  	merge_trees = renames->merge_trees;
> -	/* merge_trees[0..2] will only be NULL if opti is */
> +
> +	/*
> +	 * Handle case where previous merge operation did not want cache to
> +	 * take effect, e.g. because rename/rename(1to1) makes it invalid.
> +	 */
> +	if (!merge_trees[0]) {
> +		assert(!merge_trees[0] && !merge_trees[1] && !merge_trees[2]);
> +		renames->cached_pairs_valid_side = 0; /* neither side valid */
> +		return;
> +	}
> +
> +	/*
> +	 * Handle other cases; note that merge_trees[0..2] will only
> +	 * be NULL if opti is, or if all three were manually set to
> +	 * NULL by e.g. rename/rename(1to1) handling.
> +	 */
>  	assert(merge_trees[0] && merge_trees[1] && merge_trees[2]);

Thanks,
-Stolee

  reply	other threads:[~2021-05-17 14:46 UTC|newest]

Thread overview: 61+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-24 21:32 [PATCH 0/7] Optimization batch 11: avoid repeatedly detecting same renames Elijah Newren via GitGitGadget
2021-03-24 21:32 ` [PATCH 1/7] merge-ort: add data structures for in-memory caching of rename detection Elijah Newren via GitGitGadget
2021-03-24 21:32 ` [PATCH 2/7] merge-ort: populate caches of rename detection results Elijah Newren via GitGitGadget
2021-03-24 21:32 ` [PATCH 3/7] merge-ort: add code to check for whether cached renames can be reused Elijah Newren via GitGitGadget
2021-03-24 21:32 ` [PATCH 4/7] merge-ort: avoid accidental API mis-use Elijah Newren via GitGitGadget
2021-03-24 21:32 ` [PATCH 5/7] merge-ort: preserve cached renames for the appropriate side Elijah Newren via GitGitGadget
2021-03-24 21:32 ` [PATCH 6/7] merge-ort: add helper functions for using cached renames Elijah Newren via GitGitGadget
2021-03-24 21:32 ` [PATCH 7/7] merge-ort, diffcore-rename: employ cached renames when possible Elijah Newren via GitGitGadget
2021-03-24 22:04 ` [PATCH 0/7] Optimization batch 11: avoid repeatedly detecting same renames Junio C Hamano
2021-03-24 23:25   ` Elijah Newren
2021-03-25 18:59     ` Junio C Hamano
2021-03-29 22:34       ` Elijah Newren
2021-03-30 12:07         ` Derrick Stolee
2021-05-04  2:12 ` [PATCH v2 00/13] " Elijah Newren via GitGitGadget
2021-05-04  2:12   ` [PATCH v2 01/13] t6423: rename file within directory that other side renamed Elijah Newren via GitGitGadget
2021-05-04  2:12   ` [PATCH v2 02/13] Documentation/technical: describe remembering renames optimization Elijah Newren via GitGitGadget
2021-05-04  2:12   ` [PATCH v2 03/13] fast-rebase: change assert() to BUG() Elijah Newren via GitGitGadget
2021-05-04  2:12   ` [PATCH v2 04/13] fast-rebase: write conflict state to working tree, index, and HEAD Elijah Newren via GitGitGadget
2021-05-17 13:32     ` Derrick Stolee
2021-05-18  3:42       ` Elijah Newren
2021-05-18 13:54         ` Derrick Stolee
2021-05-04  2:12   ` [PATCH v2 05/13] t6429: testcases for remembering renames Elijah Newren via GitGitGadget
2021-05-04  2:12   ` [PATCH v2 06/13] merge-ort: add data structures for in-memory caching of rename detection Elijah Newren via GitGitGadget
2021-05-17 13:41     ` Derrick Stolee
2021-05-18  3:55       ` Elijah Newren
2021-05-18 13:57         ` Derrick Stolee
2021-05-04  2:12   ` [PATCH v2 07/13] merge-ort: populate caches of rename detection results Elijah Newren via GitGitGadget
2021-05-17 13:51     ` Derrick Stolee
2021-05-20  0:48       ` Elijah Newren
2021-05-04  2:12   ` [PATCH v2 08/13] merge-ort: add code to check for whether cached renames can be reused Elijah Newren via GitGitGadget
2021-05-17 14:01     ` Derrick Stolee
2021-05-04  2:12   ` [PATCH v2 09/13] merge-ort: avoid accidental API mis-use Elijah Newren via GitGitGadget
2021-05-17 14:10     ` Derrick Stolee
2021-05-04  2:12   ` [PATCH v2 10/13] merge-ort: preserve cached renames for the appropriate side Elijah Newren via GitGitGadget
2021-05-04  2:12   ` [PATCH v2 11/13] merge-ort: add helper functions for using cached renames Elijah Newren via GitGitGadget
2021-05-04  2:12   ` [PATCH v2 12/13] merge-ort: handle interactions of caching and rename/rename(1to1) cases Elijah Newren via GitGitGadget
2021-05-17 14:16     ` Derrick Stolee [this message]
2021-05-04  2:12   ` [PATCH v2 13/13] merge-ort, diffcore-rename: employ cached renames when possible Elijah Newren via GitGitGadget
2021-05-17 14:23     ` Derrick Stolee
2021-05-20  0:36       ` Elijah Newren
2021-05-22 11:17         ` Derrick Stolee
2021-05-14 17:37   ` [PATCH v2 00/13] Optimization batch 11: avoid repeatedly detecting same renames Elijah Newren
2021-05-14 21:04     ` Derrick Stolee
2021-05-20  6:09   ` [PATCH v3 " Elijah Newren via GitGitGadget
2021-05-20  6:09     ` [PATCH v3 01/13] t6423: rename file within directory that other side renamed Elijah Newren via GitGitGadget
2021-05-20  6:09     ` [PATCH v3 02/13] Documentation/technical: describe remembering renames optimization Elijah Newren via GitGitGadget
2021-05-20 11:32       ` Bagas Sanjaya
2021-05-20 15:14         ` Kerry, Richard
2021-05-20 16:34         ` Elijah Newren
2021-05-20  6:09     ` [PATCH v3 03/13] fast-rebase: change assert() to BUG() Elijah Newren via GitGitGadget
2021-05-20  6:09     ` [PATCH v3 04/13] fast-rebase: write conflict state to working tree, index, and HEAD Elijah Newren via GitGitGadget
2021-05-20  6:09     ` [PATCH v3 05/13] t6429: testcases for remembering renames Elijah Newren via GitGitGadget
2021-05-20  6:09     ` [PATCH v3 06/13] merge-ort: add data structures for in-memory caching of rename detection Elijah Newren via GitGitGadget
2021-05-20  6:09     ` [PATCH v3 07/13] merge-ort: populate caches of rename detection results Elijah Newren via GitGitGadget
2021-05-20  6:09     ` [PATCH v3 08/13] merge-ort: add code to check for whether cached renames can be reused Elijah Newren via GitGitGadget
2021-05-20  6:09     ` [PATCH v3 09/13] merge-ort: avoid accidental API mis-use Elijah Newren via GitGitGadget
2021-05-20  6:09     ` [PATCH v3 10/13] merge-ort: preserve cached renames for the appropriate side Elijah Newren via GitGitGadget
2021-05-20  6:09     ` [PATCH v3 11/13] merge-ort: add helper functions for using cached renames Elijah Newren via GitGitGadget
2021-05-20  6:09     ` [PATCH v3 12/13] merge-ort: handle interactions of caching and rename/rename(1to1) cases Elijah Newren via GitGitGadget
2021-05-20  6:09     ` [PATCH v3 13/13] merge-ort, diffcore-rename: employ cached renames when possible Elijah Newren via GitGitGadget
2021-05-22 11:17     ` [PATCH v3 00/13] Optimization batch 11: avoid repeatedly detecting same renames Derrick Stolee

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