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From: "Elijah Newren via GitGitGadget" <gitgitgadget@gmail.com>
To: 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>,
	Derrick Stolee <stolee@gmail.com>,
	Elijah Newren <newren@gmail.com>,
	Elijah Newren <newren@gmail.com>
Subject: [PATCH v3 12/13] merge-ort: handle interactions of caching and rename/rename(1to1) cases
Date: Thu, 20 May 2021 06:09:40 +0000	[thread overview]
Message-ID: <886a17115f30b97fd8c021495f228a45b9f76636.1621490982.git.gitgitgadget@gmail.com> (raw)
In-Reply-To: <pull.859.v3.git.1621490982.gitgitgadget@gmail.com>

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 9a229128a9a0..2cdc57e75543 100644
--- a/merge-ort.c
+++ b/merge-ort.c
@@ -2111,6 +2111,9 @@ 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],
@@ -2120,6 +2123,16 @@ 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;
+
 				/* We handled both renames, i.e. i+1 handled */
 				i++;
 				/* Move to next rename */
@@ -3910,7 +3923,22 @@ 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]);
 
 	/* Check if we meet a condition for re-using cached_pairs */
-- 
gitgitgadget


  parent reply	other threads:[~2021-05-20  6:10 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
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     ` Elijah Newren via GitGitGadget [this message]
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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