view tests/test-copies-unrelated.t @ 42621:99ebde4fec99

commit: improve the files field of changelog for merges

Currently, the files list of merge commits repeats all the deletions
(either actual deletions, or files that got renamed) that happened
between base and p2 of the merge. If p2 is the main branch, the list
can easily be much bigger than the change being merged.

This results in various problems worth improving:
- changelog is bigger than necessary
- `hg log directory` lists many unrelated merge commits, and `hg log
  -v -r commit` frequently fills multiple screens worth of files
- it possibly slows down adjustlinkrev, by forcing it to read more
  manifests, and that function can certainly be a bottleneck
- the server side of pulls can waste a lot of time simply opening the
  filelogs for pointless files (the constant factors for opening even
  a tiny filelog is apparently pretty bad)

So stop listing such files as described in the code.  Impacted merge
commits and their descendants get a different hash than they would
have without this. This doesn't seem problematic, except for
convert. The previous commit helped with that in the hg->hg case (but
if you do svn->hg twice from scratch, hashes can still change).

The rest of the description is numbers. I don't have much to report,
because recreating the files list of existing repositories is not
easy:
- debugupgradeformat and bundle/unbundle don't recreate the list
- export/import tends to choke quickly applying patches or on
  description that contain diffs,
- merge commits from the convert extension don't have the right files
  list for reasons orthogonal to the current commit
- replaying the merge with hg update/hg merge/hg revert --all/hg
  commit can end up failing in hg revert
- I wasn't sure that using debugsetparents + debugrebuilddirstate
  would really build the right thing

I measured commit time before and after this change, in a case with no
files filtered out, several files filtered out (no difference) and 5k
files filtered out (+1% time).

Recreating the 100 more recent merges in a private repo, the
concatenated uncompressed files lists goes from 1.12MB to
0.52MB. Excluding 3 merges that are not representative, then the size
goes from 570k to 15k.
I converted part of mozilla-central, and observed file list shrinking
quite a bit too, starting at the very first merge, 733641d9feaf, going
from 550 files to 10 files (although they have relatively few merges,
so they probably wouldn't care).

Differential Revision: https://phab.mercurial-scm.org/D6613

#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)