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Differential D6420

copies: don't filter out copy targets created on other side of merge commit
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Authored by martinvonz on May 21 2019, 8:32 PM.

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rHG35d674a3d5db: copies: don't filter out copy targets created on other side of merge commit

Summary

If file X is copied to Y on one side of merge and the other side
creates Y (no copy), we would not mark that as copy. In the
changeset-centric pathcopies() version, that was done by checking if
the copy target existed on the other branch. Even though merge commits
are pretty uncommon, it still turned out to be too expensive to load
the manifest of the parents of merge commits. In a repo of
mozilla-unified converted to storing copies in changesets, about 2m30s
of hg debugpathcopies FIREFOX_BETA_59_END FIREFOX_BETA_60_BASE is
spent on this check of merge commits.

I tried to think of a way of storing more information in the
changesets in order to cheaply detect these cases, but I couldn't
think of a solution. So this patch simply removes those checks.

For reference, these extra copies are reported from the aforementioned
command after this patch:

browser/base/content/sanitize.js -> browser/modules/Sanitizer.jsm
testing/mozbase/mozprocess/tests/process_normal_finish_python.ini -> testing/mozbase/mozprocess/tests/process_normal_finish.ini
testing/mozbase/mozprocess/tests/process_waittimeout_python.ini -> testing/mozbase/mozprocess/tests/process_waittimeout.ini
testing/mozbase/mozprocess/tests/process_waittimeout_10s_python.ini -> testing/mozbase/mozprocess/tests/process_waittimeout_10s.ini

Since these copies were created on one side of some merge, it still
seems reasonable to include them, so I'm not even sure it's worse than
filelog pathcopies(), just different.

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rHG Mercurial

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Event Timeline

martinvonz created this revision.May 21 2019, 8:32 PM

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martinvonz added a child revision: D6421: copies: avoid unnecessary copying of copy dict.May 21 2019, 8:32 PM

martinvonz added a commit: rHG35d674a3d5db: copies: don't filter out copy targets created on other side of merge commit.Jun 17 2019, 1:33 PM

This revision was not accepted when it landed; it landed in state Needs Review.

Closed by commit rHG35d674a3d5db: copies: don't filter out copy targets created on other side of merge commit (authored by martinvonz). · Explain Why

This revision was automatically updated to reflect the committed changes.

Revision Contents
Changeset List

			Path	Packages
M			mercurial/copies.py (23 lines)
M			tests/test-copies.t (9 lines)

Status	Author	Revision
Closed	martinvonz	D6422 copies: avoid calling matcher if matcher.always()
Closed	martinvonz	D6421 copies: avoid unnecessary copying of copy dict
Closed	martinvonz	D6420 copies: don't filter out copy targets created on other side of merge commit
Closed	martinvonz	D6419 copies: do full filtering at end of _changesetforwardcopies()
Closed	martinvonz	D6418 copies: split up _chain() in naive chaining and filtering steps
Closed	martinvonz	D6417 context: get filesadded() and filesremoved() from changeset if configured
Closed	martinvonz	D6416 changelog: optionally store added and removed files in changeset extras
Closed	martinvonz	D6369 templatekw: make {file_*} compare to both merge parents (issue4292)
Closed	martinvonz	D6370 templatekw: move showfileadds() close to showfile{mods,dels}()
Closed	martinvonz	D6368 tests: add test for {file_mods}, {file_adds}, {file_dels} on merge commit
Closed	martinvonz	D6367 context: add ctx.files{modified,added,removed}() methods

Diff 15544

mercurial/copies.py

	work = [(r, 1, {}) for r in roots]			work = [(r, 1, {}) for r in roots]
	heapq.heapify(work)			heapq.heapify(work)
	while work:			while work:
	r, i1, copies1 = heapq.heappop(work)			r, i1, copies1 = heapq.heappop(work)
	if work and work[0][0] == r:			if work and work[0][0] == r:
	# We are tracing copies from both parents			# We are tracing copies from both parents
	r, i2, copies2 = heapq.heappop(work)			r, i2, copies2 = heapq.heappop(work)
	copies = {}			copies = {}
	ctx = repo[r]
	p1man, p2man = ctx.p1().manifest(), ctx.p2().manifest()
	allcopies = set(copies1) \| set(copies2)			allcopies = set(copies1) \| set(copies2)
	# TODO: perhaps this filtering should be done as long as ctx			# TODO: perhaps this filtering should be done as long as ctx
	# is merge, whether or not we're tracing from both parent.			# is merge, whether or not we're tracing from both parent.
	for dst in allcopies:			for dst in allcopies:
	if not match(dst):			if not match(dst):
	continue			continue
	if dst not in copies2:			# Unlike when copies are stored in the filelog, we consider
	# Copied on p1 side: mark as copy from p1 side if it didn't			# it a copy even if the destination already existed on the
	# already exist on p2 side			# other branch. It's simply too expensive to check if the
	if dst not in p2man:			# file existed in the manifest.
				if dst in copies1:
				# If it was copied on the p1 side, mark it as copied from
				# that side, even if it was also copied on the p2 side.
	copies[dst] = copies1[dst]			copies[dst] = copies1[dst]
	elif dst not in copies1:
	# Copied on p2 side: mark as copy from p2 side if it didn't
	# already exist on p1 side
	if dst not in p1man:
	copies[dst] = copies2[dst]
	else:			else:
	# Copied on both sides: mark as copy from p1 side			copies[dst] = copies2[dst]
	copies[dst] = copies1[dst]
	else:			else:
	copies = copies1			copies = copies1
	if r == b.rev():			if r == b.rev():
	_filter(a, b, copies)			_filter(a, b, copies)
	return copies			return copies
	for c in children[r]:			for c in children[r]:
	childctx = repo[c]			childctx = repo[c]
	if r == childctx.p1().rev():			if r == childctx.p1().rev():

tests/test-copies.t

	x			x
	$ hg debugp1copies -r 3			$ hg debugp1copies -r 3
	y -> z			y -> z
	$ hg debugp2copies -r 3			$ hg debugp2copies -r 3
	$ hg debugpathcopies 2 3			$ hg debugpathcopies 2 3
	y -> z			y -> z
	$ hg debugpathcopies 1 3			$ hg debugpathcopies 1 3

	Create x and y, then rename x to z on one side of merge, and rename y to z and modify z on the			Create x and y, then rename x to z on one side of merge, and rename y to z and
	other side.			modify z on the other side. When storing copies in the changeset, we don't
				filter out copies whose target was created on the other side of the merge.
	$ newrepo			$ newrepo
	$ echo x > x			$ echo x > x
	$ echo y > y			$ echo y > y
	$ hg ci -Aqm 'add x and y'			$ hg ci -Aqm 'add x and y'
	$ hg mv x z			$ hg mv x z
	$ hg ci -qm 'rename x to z'			$ hg ci -qm 'rename x to z'
	$ hg co -q 0			$ hg co -q 0
	$ hg mv y z			$ hg mv y z
	\| \| z			\| \| z
	\| o 2 rename y to z			\| o 2 rename y to z
	\| \| y z			\| \| y z
	o \| 1 rename x to z			o \| 1 rename x to z
	\|/ x z			\|/ x z
	o 0 add x and y			o 0 add x and y
	x y			x y
	$ hg debugpathcopies 1 4			$ hg debugpathcopies 1 4
				y -> z (no-filelog !)
	$ hg debugpathcopies 2 4			$ hg debugpathcopies 2 4
				x -> z (no-filelog !)
	$ hg debugpathcopies 0 4			$ hg debugpathcopies 0 4
	x -> z (filelog !)			x -> z (filelog !)
	y -> z (compatibility !)			y -> z (compatibility !)
	$ hg debugpathcopies 1 5			$ hg debugpathcopies 1 5
				y -> z (no-filelog !)
	$ hg debugpathcopies 2 5			$ hg debugpathcopies 2 5
				x -> z (no-filelog !)
	$ hg debugpathcopies 0 5			$ hg debugpathcopies 0 5
	x -> z			x -> z


	Test for a case in fullcopytracing algorithm where neither of the merging csets			Test for a case in fullcopytracing algorithm where neither of the merging csets
	is a descendant of the merge base. This test reflects that the algorithm			is a descendant of the merge base. This test reflects that the algorithm
	correctly finds the copies:			correctly finds the copies:

Diff	ID	Description	Created	Lint	Unit
Base		Base
Diff 1	15218		May 21 2019, 8:32 PM	★	★
Diff 2	15544	rHG35d674a3d5db319b47560f1ef8949b0f77c1cafb	Apr 19 2019, 12:22 AM	★	★