mercurial/metadata.py
300	I found that listing the symmetrical cases as separate (B/G, C/H, D/I, E/J, F/K and N/O) rather than the same to be confusing. Maybe just reuse the same letter for each pair?
394	I'm not entirely sure I understand how sure a case happens. For example repository have some commit where the new node is an ancestor of the node in parent-A That sounds like a cycle, so I'm sure I'm just confused parent-A and parent-B are two branches of the same file history, yet not merge-filenode were created How is that even possible?

mercurial/metadata.py
300	They are the same, but we arrive to them from slightly different angle. So I prefer to have a distinct letter for them because you never know what can hide in these angles.
394	I'm not entirely sure I understand how sure a case happens. This happened when a bugged client, created a bugged manifest. This is bad, but this happened in the past. They are no cycle in the filelog history.

			Path	Packages
M			mercurial/metadata.py (227 lines)

Diff	ID	Description	Created	Lint	Unit
Base		Base
Diff 1	22948		Sep 30 2020, 9:11 AM	★	★
Diff 2	22958		Sep 30 2020, 9:36 PM	★	★
Diff 3	22987		Oct 2 2020, 3:14 AM	★	★
Diff 4	22995		Oct 2 2020, 5:09 AM	★	★
Diff 5	23015		Oct 2 2020, 12:40 PM	★	★
Diff 6	23092	rHG0c171327bc11a5ec0d66359bfb4752a4ab5b4c61	Sep 29 2020, 4:47 PM	★	★

Commit	Parents	Author	Summary	Date
52090aa4f456	f13657385a74	Pierre-Yves David		Sep 29 2020, 4:47 PM

Status	Author	Revision
Closed	marmoute	D9113 copies: rename some function to the new naming scheme
Closed	marmoute	D9112 changing-files: cache the various property
Closed	marmoute	D9111 changing-files: always use `mark_touched` to update the touched set
Closed	marmoute	D9141 copies: move `merged` testing sooner
Closed	marmoute	D9140 copies: return None instead of ChangingFiles when relevant
Closed	marmoute	D9139 copies: add a HASCOPIESINFO flag to highlight rev with useful data
Closed	marmoute	D9130 salvaged: properly deal with salvaged file during copy tracing
Closed	marmoute	D9129 salvaged: persist the salvaged set on disk
Closed	marmoute	D9128 changing-files: add clean computation of changed file for merges
Closed	marmoute	D9127 changing-files: add clean computation of changed files for linear changesets
Closed	marmoute	D9126 changing-files: add clean computation of changed files for roots
Closed	marmoute	D9125 changing-files: add a debug command display changed files
Closed	marmoute	D9124 side-data: add a test to check sidedata upgrade
Closed	marmoute	D9123 changing-files: split the changing files computation from encoding
Closed	marmoute	D9120 salvaged: record salvaged in ChangingFiles at commit time
Closed	marmoute	D9119 salvaged: track removal-candidates in more cases
Closed	marmoute	D9122 salvaged: explicitly skip salvaged file while encoding
Closed	marmoute	D9118 changing-files: add a "salvaged" set to track file that were not removed
Closed	marmoute	D9117 copies: directly pass a changes object to the copy tracing code
Closed	marmoute	D9116 copies: no longer change the sidedata flag
Closed	marmoute	D9115 copies: use dedicated `_revinfo_getter` function and call
Closed	marmoute	D9114 copies: make two version of the changeset centric algorithm
Closed	marmoute	D9092 changing-files: retrieve changelogrevision.files from the sidedata block
Closed	marmoute	D9091 changing-files: drop the now useless changelogrevision argument
Closed	marmoute	D9090 changing-files: rework the way we store changed files in side-data
Closed	marmoute	D9143 changing-files: fix docstring

Diff 22958

mercurial/metadata.py

				# coding: utf8
	# metadata.py -- code related to various metadata computation and access.			# metadata.py -- code related to various metadata computation and access.
	#			#
	# Copyright 2019 Google, Inc <martinvonz@google.com>			# Copyright 2019 Google, Inc <martinvonz@google.com>
	# Copyright 2020 Pierre-Yves David <pierre-yves.david@octobus.net>			# Copyright 2020 Pierre-Yves David <pierre-yves.david@octobus.net>
	#			#
	# This software may be used and distributed according to the terms of the			# This software may be used and distributed according to the terms of the
	# GNU General Public License version 2 or any later version.			# GNU General Public License version 2 or any later version.
	from __future__ import absolute_import, print_function			from __future__ import absolute_import, print_function
	elif p1.rev() != node.nullrev and p2.rev() == node.nullrev:			elif p1.rev() != node.nullrev and p2.rev() == node.nullrev:
	return _process_linear(p1, ctx)			return _process_linear(p1, ctx)
	elif p1.rev() == node.nullrev and p2.rev() != node.nullrev:			elif p1.rev() == node.nullrev and p2.rev() != node.nullrev:
	# In the wild, one can encounter changeset where p1 is null but p2 is not			# In the wild, one can encounter changeset where p1 is null but p2 is not
	return _process_linear(p1, ctx, parent=2)			return _process_linear(p1, ctx, parent=2)
	elif p1.rev() == p2.rev():			elif p1.rev() == p2.rev():
	# In the wild, one can encounter such "non-merge"			# In the wild, one can encounter such "non-merge"
	return _process_linear(p1, ctx)			return _process_linear(p1, ctx)
	filescopies = computechangesetcopies(ctx)			else:
	filesadded = computechangesetfilesadded(ctx)			return _process_merge(p1, p2, ctx)
	filesremoved = computechangesetfilesremoved(ctx)
	filesmerged = computechangesetfilesmerged(ctx)
	files = ChangingFiles()
	files.update_touched(ctx.files())
	files.update_added(filesadded)
	files.update_removed(filesremoved)
	files.update_merged(filesmerged)
	files.update_copies_from_p1(filescopies[0])
	files.update_copies_from_p2(filescopies[1])
	return files


	def _process_root(ctx):			def _process_root(ctx):
	"""compute the appropriate changed files for a changeset with no parents			"""compute the appropriate changed files for a changeset with no parents
	"""			"""
	# Simple, there was nothing before it, so everything is added.			# Simple, there was nothing before it, so everything is added.
	md = ChangingFiles()			md = ChangingFiles()
	manifest = ctx.manifest()			manifest = ctx.manifest()
	copy_info = children_ctx[filename].renamed()			copy_info = children_ctx[filename].renamed()
	if copy_info:			if copy_info:
	source, srcnode = copy_info			source, srcnode = copy_info
	copied(source, filename)			copied(source, filename)

	return md			return md


				def _process_merge(p1_ctx, p2_ctx, ctx):
				"""compute the appropriate changed files for a changeset with two parents

				This is a more advance case. The information we need to record is summarise
				in the following table:

				┌──────────────┬──────────────┬──────────────┬──────────────┬──────────────┐
				│ diff ╲ diff │ ø │ (Some, None) │ (None, Some) │ (Some, Some) │
				AlphareUnsubmitted Not Done I found that listing the symmetrical cases as separate (B/G, C/H, D/I, E/J, F/K and N/O) rather than the same to be confusing. Maybe just reuse the same letter for each pair? Alphare: I found that listing the symmetrical cases as separate (B/G, C/H, D/I, E/J, F/K and N/O)…
				marmouteAuthorUnsubmitted Done They are the same, but we arrive to them from slightly different angle. So I prefer to have a distinct letter for them because you never know what can hide in these angles. marmoute: They are the same, but we arrive to them from slightly different angle. So I prefer to have a…
				│ p2 ╲ p1 │ │ │ │ │
				├──────────────┼──────────────┼──────────────┼──────────────┼──────────────┤
				│ │ │🄱 No Changes │🄳 No Changes │ │
				│ ø │🄰 No Changes │ OR │ OR │🄵 No Changes │
				│ │ │🄲 Deleted[1] │🄴 Salvaged[2]│ [3] │
				├──────────────┼──────────────┼──────────────┼──────────────┼──────────────┤
				│ │🄶 No Changes │ │ │ │
				│ (Some, None) │ OR │🄻 Deleted │ ø │ ø │
				│ │🄷 Deleted[1] │ │ │ │
				├──────────────┼──────────────┼──────────────┼──────────────┼──────────────┤
				│ │🄸 No Changes │ │ │ │
				│ (None, Some) │ OR │ ø │🄼 Added │🄽 Merged │
				│ │🄹 Salvaged[2]│ │ (copied?) │ (copied?) │
				├──────────────┼──────────────┼──────────────┼──────────────┼──────────────┤
				│ │ │ │ │ │
				│ (Some, Some) │🄺 No Changes │ ø │🄾 Merged │🄿 Merged │
				│ │ [3] │ │ (copied?) │ (copied?) │
				└──────────────┴──────────────┴──────────────┴──────────────┴──────────────┘

				Special case [1]:

				The situation is:
				- parent-A: file exists,
				- parent-B: no file,
				- working-copy: no file.

				Detecting a "deletion" will depend on the presence of actual change on
				the "parent-A" branch:

				Subcase 🄱 or 🄶 : if the state of the file in "parent-A" is unchanged
				compared to the merge ancestors, then parent-A branch left the file
				untouched while parent-B deleted it. We simply apply the change from
				"parent-B" branch the file was automatically dropped.
				The result is:
				- file is not recorded as touched by the merge.

				Subcase 🄲 or 🄷 : otherwise, the change from parent-A branch were explicitly dropped and
				the file was "deleted again". From a user perspective, the message
				about "locally changed" while "remotely deleted" (or the other way
				around) was issued and the user chose to deleted the file.
				The result:
				- file is recorded as touched by the merge.


				Special case [2]:

				The situation is:
				- parent-A: no file,
				- parent-B: file,
				- working-copy: file (same content as parent-B).

				There are three subcases depending on the ancestors contents:

				- A) the file is missing in all ancestors,
				- B) at least one ancestor has the file with filenode ≠ from parent-B,
				- C) all ancestors use the same filenode as parent-B,

				Subcase (A) is the simpler, nothing happend on parent-A side while
				parent-B added it.

				The result:
				- the file is not marked as touched by the merge.

				Subcase (B) is the counter part of "Special case [1]", the file was
				modified on parent-B side, while parent-A side deleted it. However this
				time, the conflict was solved by keeping the file (and its
				modification). We consider the file as "salvaged".

				The result:
				- the file is marked as "salvaged" by the merge.

				Subcase (C) is subtle variation of the case above. In this case, the
				file in unchanged on the parent-B side and actively removed on the
				parent-A side. So the merge machinery correctly decide it should be
				removed. However, the file was explicitly restored to its parent-B
				content before the merge was commited. The file is be marked
				as salvaged too. From the merge result perspective, this is similar to
				Subcase (B), however from the merge resolution perspective they differ
				since in (C), there was some conflict not obvious solution to the
				merge (That got reversed)

				Special case [3]:

				The situation is:
				- parent-A: file,
				- parent-B: file (different filenode as parent-A),
				- working-copy: file (same filenode as parent-B).

				This case is in theory much simple, for this to happens, this mean the
				filenode in parent-A is purely replacing the one in parent-B (either a
				descendant, or a full new file history, see changeset). So the merge
				introduce no changes, and the file is not affected by the merge...

				However, in the wild it is possible to find commit with the above is not
				AlphareUnsubmitted Not Done I'm not entirely sure I understand how sure a case happens. For example repository have some commit where the new node is an ancestor of the node in parent-A That sounds like a cycle, so I'm sure I'm just confused parent-A and parent-B are two branches of the same file history, yet not merge-filenode were created How is that even possible? Alphare: I'm not entirely sure I understand how sure a case happens. > For example repository have some…
				marmouteAuthorUnsubmitted Done I'm not entirely sure I understand how sure a case happens. This happened when a bugged client, created a bugged manifest. This is bad, but this happened in the past. They are no cycle in the filelog history. marmoute: > I'm not entirely sure I understand how sure a case happens. This happened when a bugged…
				True. For example repository have some commit where the new node is an
				ancestor of the node in parent-A, or where parent-A and parent-B are two
				branches of the same file history, yet not merge-filenode were created
				(while the "merge" should have led to a "modification").

				Detecting such cases (and not recording the file as modified) would be a
				nice bonus. However do not any of this yet.
				"""

				md = ChangingFiles()

				m = ctx.manifest()
				p1m = p1_ctx.manifest()
				p2m = p2_ctx.manifest()
				diff_p1 = p1m.diff(m)
				diff_p2 = p2m.diff(m)

				cahs = ctx.repo().changelog.commonancestorsheads(
				p1_ctx.node(), p2_ctx.node()
				)
				if not cahs:
				cahs = [node.nullrev]
				mas = [ctx.repo()[r].manifest() for r in cahs]

				copy_candidates = []

				# Dealing with case 🄰 happens automatically. Since there are no entry in
				# d1 nor d2, we won't iterate on it ever.

				# Iteration over d1 content will deal with all cases, but the one in the
				# first column of the table.
				for filename, d1 in diff_p1.items():

				d2 = diff_p2.pop(filename, None)

				if d2 is None:
				# this deal with the first line of the table.
				_process_other_unchanged(md, mas, filename, d1)
				else:

				if d1[0][0] is None and d2[0][0] is None:
				# case 🄼 — both deleted the file.
				md.mark_added(filename)
				copy_candidates.append(filename)
				elif d1[1][0] is None and d2[1][0] is None:
				# case 🄻 — both deleted the file.
				md.mark_removed(filename)
				elif d1[1][0] is not None and d2[1][0] is not None:
				# case 🄽 🄾 🄿
				md.mark_merged(filename)
				copy_candidates.append(filename)
				else:
				# Impossible case, the post-merge file status cannot be None on
				# one side and Something on the other side.
				assert False, "unreachable"

				# Iteration over remaining d2 content deal with the first column of the
				# table.
				for filename, d2 in diff_p2.items():
				_process_other_unchanged(md, mas, filename, d2)

				for filename in copy_candidates:
				copy_info = ctx[filename].renamed()
				if copy_info:
				source, srcnode = copy_info
				if source in p1_ctx and p1_ctx[source].filenode() == srcnode:
				md.mark_copied_from_p1(source, filename)
				elif source in p2_ctx and p2_ctx[source].filenode() == srcnode:
				md.mark_copied_from_p2(source, filename)
				return md


				def _find(manifest, filename):
				"""return the associate filenode or None"""
				if filename not in manifest:
				return None
				return manifest.find(filename)[0]


				def _process_other_unchanged(md, mas, filename, diff):
				source_node = diff[0][0]
				target_node = diff[1][0]

				if source_node is not None and target_node is None:
				if any(not _find(ma, filename) == source_node for ma in mas):
				# case 🄲 of 🄷
				md.mark_removed(filename)
				# else, we have case 🄱 or 🄶 : no change need to be recorded
				elif source_node is None and target_node is not None:
				if any(_find(ma, filename) is not None for ma in mas):
				# case 🄴 or 🄹
				md.mark_salvaged(filename)
				# else, we have case 🄳 or 🄸 : simple merge without intervention
				elif source_node is not None and target_node is not None:
				# case 🄵 or 🄺 : simple merge without intervention
				#
				# In buggy case where source_node is not an ancestors of target_node.
				# There should have a been a new filenode created, recording this as
				# "modified". We do not deal with them yet.
				pass
				else:
				# An impossible case, the diff algorithm should not return entry if the
				# file is missing on both side.
				assert False, "unreachable"


				def _missing_from_all_ancestors(mas, filename):
				return all(_find(ma, filename) is None for ma in mas)


	def computechangesetfilesadded(ctx):			def computechangesetfilesadded(ctx):
	"""return the list of files added in a changeset			"""return the list of files added in a changeset
	"""			"""
	added = []			added = []
	for f in ctx.files():			for f in ctx.files():
	if not any(f in p for p in ctx.parents()):			if not any(f in p for p in ctx.parents()):
	added.append(f)			added.append(f)
	return added			return added

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changing-files: add clean computation of changed file for merges
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Diff 22958

mercurial/metadata.py

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changing-files: add clean computation of changed file for mergesClosedPublic

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Diff 22958

mercurial/metadata.py

changing-files: add clean computation of changed file for merges
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