( )⚙ D6274 copies: document cases in _chain()

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Differential D6274

copies: document cases in _chain()
ClosedPublic

Authored by martinvonz on Apr 18 2019, 12:55 PM.

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rHGd1c2688eda80: copies: document cases in _chain()
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rHG Mercurial
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martinvonz created this revision.Apr 18 2019, 12:55 PM
martinvonz added inline comments.Apr 18 2019, 1:49 PM
mercurial/copies.py
120–125

I just realized that using a, b, c as filenames is confusing since a and b are also the names of the copy dicts. I'll rename the files to x, y, z.

martinvonz updated this revision to Diff 14846.Apr 18 2019, 1:58 PM
martinvonz added a comment.Apr 25 2019, 1:14 AM

I think the rest of the stack from this patch are independent of the ones before, so if reviewers are intimidated by D6255, they should still be able to take this section of the stack.

martinvonz updated this revision to Diff 14948.Apr 28 2019, 3:00 AM
martinvonz updated this revision to Diff 14969.Apr 29 2019, 6:52 PM
Closed by commit rHGd1c2688eda80: copies: document cases in _chain() (authored by martinvonz). · Explain WhyMay 1 2019, 10:13 PM
This revision was automatically updated to reflect the committed changes.

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Mmercurial/copies.py (32 lines)

Diff 14969

mercurial/copies.py

# #
# When _findlimit is called, a and b are revs 3 and 0, so limit will be 2, # When _findlimit is called, a and b are revs 3 and 0, so limit will be 2,
# yet the filelog has the copy information in rev 1 and we will not look # yet the filelog has the copy information in rev 1 and we will not look
# back far enough unless we also look at the a and b as candidates. # back far enough unless we also look at the a and b as candidates.
# This only occurs when a is a descendent of b or visa-versa. # This only occurs when a is a descendent of b or visa-versa.
return min(limit, a, b) return min(limit, a, b)
def _chain(src, dst, a, b): def _chain(src, dst, a, b):
"""chain two sets of copies a->b""" """chain two sets of copies 'a' and 'b'"""
# When chaining copies in 'a' (from 'src' via some other commit 'mid') with
# copies in 'b' (from 'mid' to 'dst'), we can get the different cases in the
# following table (not including trivial cases). For example, case 2 is
# where a file existed in 'src' and remained under that name in 'mid' and
# then was renamed between 'mid' and 'dst'.
#
# case src mid dst result
# 1 x y - -
# 2 x y y x->y
# 3 x y x -
# 4 x y z x->z
# 5 - x y -
# 6 x x y x->y
martinvonzAuthorUnsubmitted
Not Done

I just realized that using a, b, c as filenames is confusing since a and b are also the names of the copy dicts. I'll rename the files to x, y, z.

martinvonz: I just realized that using `a`, `b`, `c` as filenames is confusing since `a` and `b` are also…
# Initialize result ('t') from 'a'. This catches cases 1 & 2. We'll remove
# case 1 later. We'll also catch cases 3 & 4 here. Case 4 will be
# overwritten later, and case 3 will be removed later.
t = a.copy() t = a.copy()
for k, v in b.iteritems(): for k, v in b.iteritems():
if v in t: if v in t:
# found a chain # found a chain, i.e. cases 3 & 4.
if t[v] != k: if t[v] != k:
# file wasn't renamed back to itself # file wasn't renamed back to itself (i.e. case 4, not 3)
t[k] = t[v] t[k] = t[v]
if v not in dst: if v not in dst:
# chain was a rename, not a copy # chain was a rename, not a copy
# this deletes the copy for 'y' in case 4
del t[v] del t[v]
if v in src: if v in src:
# file is a copy of an existing file # file is a copy of an existing file, i.e. case 6.
t[k] = v t[k] = v
for k, v in list(t.items()): for k, v in list(t.items()):
# remove criss-crossed copies # remove criss-crossed copies, i.e. case 3
if k in src and v in dst: if k in src and v in dst:
del t[k] del t[k]
# remove copies to files that were then removed # remove copies to files that were then removed, i.e. case 1
# and file 'y' in cases 3 & 4 (in case of rename)
elif k not in dst: elif k not in dst:
del t[k] del t[k]
return t return t
def _tracefile(fctx, am, limit=node.nullrev): def _tracefile(fctx, am, limit=node.nullrev):
"""return file context that is the ancestor of fctx present in ancestor """return file context that is the ancestor of fctx present in ancestor
manifest am, stopping after the first ancestor lower than limit""" manifest am, stopping after the first ancestor lower than limit"""