view tests/test-copies-unrelated.t @ 42743:8c9a6adec67a

rust-discovery: using the children cache in add_missing

The DAG range computation often needs to get back to very old
revisions, and turns out to be disproportionately long, given
that the end goal is to remove the descendents of the given
missing revisons from the undecided set.

The fast iteration capabilities available in the Rust case make
it possible to avoid the DAG range entirely, at the cost of
precomputing the children cache, and to simply iterate on
children of the given missing revisions.

This is a case where staying on the same side of the interface
between the two languages has clear benefits.

On discoveries with initial undecided sets
small enough to bypass sampling entirely, the total cost of
computing the children cache and the subsequent iteration
becomes better than the Python + C counterpart, which relies on
reachableroots2.

For example, on a repo with more than one million revisions with
an initial undecided set of 11 elements, we get these figures:

Rust version with simple iteration
  addcommons: 57.287us
  first undecided computation: 184.278334ms
  first children cache computation: 131.056us
  addmissings iteration: 42.766us
  first addinfo total: 185.24 ms

Python + C version
  first addcommons: 0.29 ms
  addcommons 0.21 ms
  first undecided computation 191.35 ms
  addmissings 45.75 ms
  first addinfo total: 237.77 ms

On discoveries with large undecided sets, the initial price paid
makes the first addinfo slower than the Python + C version,
but that's more than compensated by the gain in sampling and
subsequent iterations.
Here's an extreme example with an undecided set of a million revisions:

Rust version:
  first undecided computation: 293.842629ms
  first children cache computation: 407.911297ms
  addmissings iteration: 34.312869ms
  first addinfo total: 776.02 ms
  taking initial sample
  query 2: sampling time: 1318.38 ms
  query 2; still undecided: 1005013, sample size is: 200
  addmissings: 143.062us

Python + C version:
  first undecided computation 298.13 ms
  addmissings 80.13 ms
  first addinfo total: 399.62 ms
  taking initial sample
  query 2: sampling time: 3957.23 ms
  query 2; still undecided: 1005013, sample size is: 200
  addmissings 52.88 ms

Differential Revision: https://phab.mercurial-scm.org/D6428

#testcases filelog compatibility changeset

  $ cat >> $HGRCPATH << EOF
  > [extensions]
  > rebase=
  > [alias]
  > l = log -G -T '{rev} {desc}\n{files}\n'
  > EOF

#if compatibility
  $ cat >> $HGRCPATH << EOF
  > [experimental]
  > copies.read-from = compatibility
  > EOF
#endif

#if changeset
  $ cat >> $HGRCPATH << EOF
  > [experimental]
  > copies.read-from = changeset-only
  > copies.write-to = changeset-only
  > EOF
#endif

  $ REPONUM=0
  $ newrepo() {
  >     cd $TESTTMP
  >     REPONUM=`expr $REPONUM + 1`
  >     hg init repo-$REPONUM
  >     cd repo-$REPONUM
  > }

Copy a file, then delete destination, then copy again. This does not create a new filelog entry.
  $ newrepo
  $ echo x > x
  $ hg ci -Aqm 'add x'
  $ echo x2 > x
  $ hg ci -m 'modify x'
  $ hg co -q 0
  $ hg cp x y
  $ hg ci -qm 'copy x to y'
  $ hg rm y
  $ hg ci -m 'remove y'
  $ hg cp -f x y
  $ hg ci -m 'copy x onto y (again)'
  $ hg l
  @  4 copy x onto y (again)
  |  y
  o  3 remove y
  |  y
  o  2 copy x to y
  |  y
  | o  1 modify x
  |/   x
  o  0 add x
     x
  $ hg debugp1copies -r 4
  x -> y
  $ hg debugpathcopies 0 4
  x -> y
  $ hg graft -r 1
  grafting 1:* "modify x" (glob)
  merging y and x to y
  $ hg co -qC 1
  $ hg graft -r 4
  grafting 4:* "copy x onto y (again)" (glob)
  merging x and y to y

Copy x to y, then remove y, then add back y. With copy metadata in the
changeset, this could easily end up reporting y as copied from x (if we don't
unmark it as a copy when it's removed). Despite x and y not being related, we
want grafts to propagate across the rename.
  $ newrepo
  $ echo x > x
  $ hg ci -Aqm 'add x'
  $ echo x2 > x
  $ hg ci -m 'modify x'
  $ hg co -q 0
  $ hg mv x y
  $ hg ci -qm 'rename x to y'
  $ hg rm y
  $ hg ci -qm 'remove y'
  $ echo x > y
  $ hg ci -Aqm 'add back y'
  $ hg l
  @  4 add back y
  |  y
  o  3 remove y
  |  y
  o  2 rename x to y
  |  x y
  | o  1 modify x
  |/   x
  o  0 add x
     x
  $ hg debugpathcopies 0 4
BROKEN: This should succeed and merge the changes from x into y
  $ hg graft -r 1
  grafting 1:* "modify x" (glob)
  file 'x' was deleted in local [local] but was modified in other [graft].
  You can use (c)hanged version, leave (d)eleted, or leave (u)nresolved.
  What do you want to do? u
  abort: unresolved conflicts, can't continue
  (use 'hg resolve' and 'hg graft --continue')
  [255]

Add x, remove it, then add it back, then rename x to y. Similar to the case
above, but here the break in history is before the rename.
  $ newrepo
  $ echo x > x
  $ hg ci -Aqm 'add x'
  $ echo x2 > x
  $ hg ci -m 'modify x'
  $ hg co -q 0
  $ hg rm x
  $ hg ci -qm 'remove x'
  $ echo x > x
  $ hg ci -Aqm 'add x again'
  $ hg mv x y
  $ hg ci -m 'rename x to y'
  $ hg l
  @  4 rename x to y
  |  x y
  o  3 add x again
  |  x
  o  2 remove x
  |  x
  | o  1 modify x
  |/   x
  o  0 add x
     x
  $ hg debugpathcopies 0 4
  x -> y
  $ hg graft -r 1
  grafting 1:* "modify x" (glob)
  merging y and x to y
  $ hg co -qC 1
  $ hg graft -r 4
  grafting 4:* "rename x to y" (glob)
  merging x and y to y

Add x, modify it, remove it, then add it back, then rename x to y. Similar to
the case above, but here the re-added file's nodeid is different from before
the break.

  $ newrepo
  $ echo x > x
  $ hg ci -Aqm 'add x'
  $ echo x2 > x
  $ hg ci -m 'modify x'
  $ echo x3 > x
  $ hg ci -qm 'modify x again'
  $ hg co -q 1
  $ hg rm x
  $ hg ci -qm 'remove x'
# Same content to avoid conflicts
  $ hg revert -r 1 x
  $ hg ci -Aqm 'add x again'
  $ hg mv x y
  $ hg ci -m 'rename x to y'
  $ hg l
  @  5 rename x to y
  |  x y
  o  4 add x again
  |  x
  o  3 remove x
  |  x
  | o  2 modify x again
  |/   x
  o  1 modify x
  |  x
  o  0 add x
     x
  $ hg debugpathcopies 0 5
  x -> y (no-filelog !)
#if no-filelog
  $ hg graft -r 2
  grafting 2:* "modify x again" (glob)
  merging y and x to y
#else
BROKEN: This should succeed and merge the changes from x into y
  $ hg graft -r 2
  grafting 2:* "modify x again" (glob)
  file 'x' was deleted in local [local] but was modified in other [graft].
  You can use (c)hanged version, leave (d)eleted, or leave (u)nresolved.
  What do you want to do? u
  abort: unresolved conflicts, can't continue
  (use 'hg resolve' and 'hg graft --continue')
  [255]
#endif
  $ hg co -qC 2
BROKEN: This should succeed and merge the changes from x into y
  $ hg graft -r 5
  grafting 5:* "rename x to y"* (glob)
  file 'x' was deleted in other [graft] but was modified in local [local].
  You can use (c)hanged version, (d)elete, or leave (u)nresolved.
  What do you want to do? u
  abort: unresolved conflicts, can't continue
  (use 'hg resolve' and 'hg graft --continue')
  [255]

Add x, remove it, then add it back, rename x to y from the first commit.
Similar to the case above, but here the break in history is parallel to the
rename.
  $ newrepo
  $ echo x > x
  $ hg ci -Aqm 'add x'
  $ hg rm x
  $ hg ci -qm 'remove x'
  $ echo x > x
  $ hg ci -Aqm 'add x again'
  $ echo x2 > x
  $ hg ci -m 'modify x'
  $ hg co -q 0
  $ hg mv x y
  $ hg ci -qm 'rename x to y'
  $ hg l
  @  4 rename x to y
  |  x y
  | o  3 modify x
  | |  x
  | o  2 add x again
  | |  x
  | o  1 remove x
  |/   x
  o  0 add x
     x
  $ hg debugpathcopies 2 4
  x -> y
  $ hg graft -r 3
  grafting 3:* "modify x" (glob)
  merging y and x to y
  $ hg co -qC 3
  $ hg graft -r 4
  grafting 4:* "rename x to y" (glob)
  merging x and y to y

Add x, remove it, then add it back, rename x to y from the first commit.
Similar to the case above, but here the re-added file's nodeid is different
from the base.
  $ newrepo
  $ echo x > x
  $ hg ci -Aqm 'add x'
  $ hg rm x
  $ hg ci -qm 'remove x'
  $ echo x2 > x
  $ hg ci -Aqm 'add x again with different content'
  $ hg co -q 0
  $ hg mv x y
  $ hg ci -qm 'rename x to y'
  $ hg l
  @  3 rename x to y
  |  x y
  | o  2 add x again with different content
  | |  x
  | o  1 remove x
  |/   x
  o  0 add x
     x
  $ hg debugpathcopies 2 3
  x -> y
BROKEN: This should merge the changes from x into y
  $ hg graft -r 2
  grafting 2:* "add x again with different content" (glob)
  $ hg co -qC 2
BROKEN: This should succeed and merge the changes from x into y
  $ hg graft -r 3
  grafting 3:* "rename x to y" (glob)
  file 'x' was deleted in other [graft] but was modified in local [local].
  You can use (c)hanged version, (d)elete, or leave (u)nresolved.
  What do you want to do? u
  abort: unresolved conflicts, can't continue
  (use 'hg resolve' and 'hg graft --continue')
  [255]

Add x on two branches, then rename x to y on one side. Similar to the case
above, but here the break in history is via the base commit.
  $ newrepo
  $ echo a > a
  $ hg ci -Aqm 'base'
  $ echo x > x
  $ hg ci -Aqm 'add x'
  $ echo x2 > x
  $ hg ci -m 'modify x'
  $ hg co -q 0
  $ echo x > x
  $ hg ci -Aqm 'add x again'
  $ hg mv x y
  $ hg ci -qm 'rename x to y'
  $ hg l
  @  4 rename x to y
  |  x y
  o  3 add x again
  |  x
  | o  2 modify x
  | |  x
  | o  1 add x
  |/   x
  o  0 base
     a
  $ hg debugpathcopies 1 4
  x -> y
  $ hg graft -r 2
  grafting 2:* "modify x" (glob)
  merging y and x to y
  $ hg co -qC 2
  $ hg graft -r 4
  grafting 4:* "rename x to y"* (glob)
  merging x and y to y

Add x on two branches, with same content but different history, then rename x
to y on one side. Similar to the case above, here the file's nodeid is
different between the branches.
  $ newrepo
  $ echo a > a
  $ hg ci -Aqm 'base'
  $ echo x > x
  $ hg ci -Aqm 'add x'
  $ echo x2 > x
  $ hg ci -m 'modify x'
  $ hg co -q 0
  $ touch x
  $ hg ci -Aqm 'add empty x'
# Same content to avoid conflicts
  $ hg revert -r 1 x
  $ hg ci -m 'modify x to match commit 1'
  $ hg mv x y
  $ hg ci -qm 'rename x to y'
  $ hg l
  @  5 rename x to y
  |  x y
  o  4 modify x to match commit 1
  |  x
  o  3 add empty x
  |  x
  | o  2 modify x
  | |  x
  | o  1 add x
  |/   x
  o  0 base
     a
  $ hg debugpathcopies 1 5
  x -> y (no-filelog !)
#if filelog
BROKEN: This should succeed and merge the changes from x into y
  $ hg graft -r 2
  grafting 2:* "modify x" (glob)
  file 'x' was deleted in local [local] but was modified in other [graft].
  You can use (c)hanged version, leave (d)eleted, or leave (u)nresolved.
  What do you want to do? u
  abort: unresolved conflicts, can't continue
  (use 'hg resolve' and 'hg graft --continue')
  [255]
#else
  $ hg graft -r 2
  grafting 2:* "modify x" (glob)
  merging y and x to y
#endif
  $ hg co -qC 2
BROKEN: This should succeed and merge the changes from x into y
  $ hg graft -r 5
  grafting 5:* "rename x to y"* (glob)
  file 'x' was deleted in other [graft] but was modified in local [local].
  You can use (c)hanged version, (d)elete, or leave (u)nresolved.
  What do you want to do? u
  abort: unresolved conflicts, can't continue
  (use 'hg resolve' and 'hg graft --continue')
  [255]

Copies via null revision (there shouldn't be any)
  $ newrepo
  $ echo x > x
  $ hg ci -Aqm 'add x'
  $ hg cp x y
  $ hg ci -m 'copy x to y'
  $ hg co -q null
  $ echo x > x
  $ hg ci -Aqm 'add x (again)'
  $ hg l
  @  2 add x (again)
     x
  o  1 copy x to y
  |  y
  o  0 add x
     x
  $ hg debugpathcopies 1 2
  $ hg debugpathcopies 2 1
  $ hg graft -r 1
  grafting 1:* "copy x to y" (glob)