view tests/test-absorb.t @ 42222:57203e0210f8

copies: calculate mergecopies() based on pathcopies()

When copies are stored in changesets, we need a changeset-centric
version of mergecopies() just like we have a changeset-centric version
of pathcopies(). I think the natural way of thinking about
mergecopies() is in terms of pathcopies() from the base to each of the
commits. So if we can rewrite mergecopies() based on two such
pathcopies() calls, we'll get the changeset-centric version for
free. That's what this patch does.

A nice bonus is that it ends up being a lot simpler. mergecopies() has
accumulated a lot of technical debt over time. One good example is the
code for dealing with grafts (the "partial/incomplete/dirty"
stuff). Since pathcopies() already deals with backwards renames and
ping-pong renames, we get that for free.

I've run tests with hard-coded debug logging for "fullcopy" and while
I haven't looked at every difference it produces, all the ones I have
looked at seemed reasonable to me. I'm a little surprised that no more
tests fail when run with '--extra-config-opt
experimental.copies.read-from=compatibility' compared to before this
patch. This patch also fixes the broken cases in test-annotate.t and
test-fastannotate.t. It also enables the part of test-copies.t that
was previously disabled exactly because mergecopies() needed to get a
changeset-centric version.

One drawback of the rewritten code is that we may now make
remotefilelog prefetch more files. We used to prefetch files that were
unique to either side of the merge compared to the other. We now
prefetch files that are unique to either side of the merge compared to
the base. This means that if you added the same file to each side, we
would not prefetch it before, but we would now. Such cases are
probably quite rare, but one likely scenario where they happen is when
moving from a commit to its successor (or the other way around). The
user will probably already have the files in the cache in such cases,
so it's probably not a big deal.

Some timings for calculating mergecopies between two revisions
(revisions shown on each line, all using the common ancestor as base):

In the hg repo:
4.8 4.9: 0.21s -> 0.21s
4.0 4.8: 0.35s -> 0.63s

In and old copy of the mozilla-unified repo:
FIREFOX_BETA_60_BASE^ FIREFOX_BETA_60_BASE: 0.82s -> 0.82s
FIREFOX_NIGHTLY_59_END FIREFOX_BETA_60_BASE: 2.5s -> 2.6s
FIREFOX_BETA_59_END FIREFOX_BETA_60_BASE: 3.9s -> 4.1s
FIREFOX_AURORA_50_BASE FIREFOX_BETA_60_BASE: 31s -> 33s

So it's measurably slower in most cases. The most significant
difference is in the hg repo between revisions 4.0 and 4.8. In that
case it seems to come from the fact that pathcopies() uses
fctx.isintroducedafter() (in _tracefile), while the old mergecopies()
used fctx.linkrev() (in _checkcopies()). That results in a single call
to filectx._adjustlinkrev(), which is responsible for the entire
difference in time (in my repo). So we pay a performance penalty but
we get more correct code (see change in
test-mv-cp-st-diff.t). Deleting the "== f.filenode()" in _tracefile()
recovers the lost performance in the hg repo.

There were are few other optimizations in _checkcopies() that I could
not measure any impact from. One was from the "seen" set. Another was
from a "continue" when the file was not in the destination manifest
(corresponding to "am" in _tracefile).

Also note that merge copies are not calculated when updating with a
clean working copy, which is probably the most common case. I
therefore think the much simpler code is worth the slowdown.

Differential Revision: https://phab.mercurial-scm.org/D6255

  $ cat >> $HGRCPATH << EOF
  > [extensions]
  > absorb=
  > EOF

  $ sedi() { # workaround check-code
  > pattern="$1"
  > shift
  > for i in "$@"; do
  >     sed "$pattern" "$i" > "$i".tmp
  >     mv "$i".tmp "$i"
  > done
  > }

  $ hg init repo1
  $ cd repo1

Do not crash with empty repo:

  $ hg absorb
  abort: no mutable changeset to change
  [255]

Make some commits:

  $ for i in 1 2 3 4 5; do
  >   echo $i >> a
  >   hg commit -A a -m "commit $i" -q
  > done

  $ hg annotate a
  0: 1
  1: 2
  2: 3
  3: 4
  4: 5

Change a few lines:

  $ cat > a <<EOF
  > 1a
  > 2b
  > 3
  > 4d
  > 5e
  > EOF

Preview absorb changes:

  $ hg absorb --print-changes --dry-run
  showing changes for a
          @@ -0,2 +0,2 @@
  4ec16f8 -1
  5c5f952 -2
  4ec16f8 +1a
  5c5f952 +2b
          @@ -3,2 +3,2 @@
  ad8b8b7 -4
  4f55fa6 -5
  ad8b8b7 +4d
  4f55fa6 +5e
  
  4 changesets affected
  4f55fa6 commit 5
  ad8b8b7 commit 4
  5c5f952 commit 2
  4ec16f8 commit 1

Run absorb:

  $ hg absorb --apply-changes
  saved backup bundle to * (glob)
  2 of 2 chunk(s) applied
  $ hg annotate a
  0: 1a
  1: 2b
  2: 3
  3: 4d
  4: 5e

Delete a few lines and related commits will be removed if they will be empty:

  $ cat > a <<EOF
  > 2b
  > 4d
  > EOF
  $ echo y | hg absorb --config ui.interactive=1
  showing changes for a
          @@ -0,1 +0,0 @@
  f548282 -1a
          @@ -2,1 +1,0 @@
  ff5d556 -3
          @@ -4,1 +2,0 @@
  84e5416 -5e
  
  3 changesets affected
  84e5416 commit 5
  ff5d556 commit 3
  f548282 commit 1
  apply changes (yn)?  y
  saved backup bundle to * (glob)
  3 of 3 chunk(s) applied
  $ hg annotate a
  1: 2b
  2: 4d
  $ hg log -T '{rev} {desc}\n' -Gp
  @  2 commit 4
  |  diff -r 1cae118c7ed8 -r 58a62bade1c6 a
  |  --- a/a	Thu Jan 01 00:00:00 1970 +0000
  |  +++ b/a	Thu Jan 01 00:00:00 1970 +0000
  |  @@ -1,1 +1,2 @@
  |   2b
  |  +4d
  |
  o  1 commit 2
  |  diff -r 84add69aeac0 -r 1cae118c7ed8 a
  |  --- a/a	Thu Jan 01 00:00:00 1970 +0000
  |  +++ b/a	Thu Jan 01 00:00:00 1970 +0000
  |  @@ -0,0 +1,1 @@
  |  +2b
  |
  o  0 commit 1
  

Non 1:1 map changes will be ignored:

  $ echo 1 > a
  $ hg absorb --apply-changes
  nothing applied
  [1]

The prompt is not given if there are no changes to be applied, even if there
are some changes that won't be applied:

  $ hg absorb
  showing changes for a
          @@ -0,2 +0,1 @@
          -2b
          -4d
          +1
  
  0 changesets affected
  nothing applied
  [1]

Insertaions:

  $ cat > a << EOF
  > insert before 2b
  > 2b
  > 4d
  > insert aftert 4d
  > EOF
  $ hg absorb -q --apply-changes
  $ hg status
  $ hg annotate a
  1: insert before 2b
  1: 2b
  2: 4d
  2: insert aftert 4d

Bookmarks are moved:

  $ hg bookmark -r 1 b1
  $ hg bookmark -r 2 b2
  $ hg bookmark ba
  $ hg bookmarks
     b1                        1:b35060a57a50
     b2                        2:946e4bc87915
   * ba                        2:946e4bc87915
  $ sedi 's/insert/INSERT/' a
  $ hg absorb -q --apply-changes
  $ hg status
  $ hg bookmarks
     b1                        1:a4183e9b3d31
     b2                        2:c9b20c925790
   * ba                        2:c9b20c925790

Non-mofified files are ignored:

  $ touch b
  $ hg commit -A b -m b
  $ touch c
  $ hg add c
  $ hg rm b
  $ hg absorb --apply-changes
  nothing applied
  [1]
  $ sedi 's/INSERT/Insert/' a
  $ hg absorb --apply-changes
  saved backup bundle to * (glob)
  2 of 2 chunk(s) applied
  $ hg status
  A c
  R b

Public commits will not be changed:

  $ hg phase -p 1
  $ sedi 's/Insert/insert/' a
  $ hg absorb -pn
  showing changes for a
          @@ -0,1 +0,1 @@
          -Insert before 2b
          +insert before 2b
          @@ -3,1 +3,1 @@
  85b4e0e -Insert aftert 4d
  85b4e0e +insert aftert 4d
  
  1 changesets affected
  85b4e0e commit 4
  $ hg absorb --apply-changes
  saved backup bundle to * (glob)
  1 of 2 chunk(s) applied
  $ hg diff -U 0
  diff -r 1c8eadede62a a
  --- a/a	Thu Jan 01 00:00:00 1970 +0000
  +++ b/a	* (glob)
  @@ -1,1 +1,1 @@
  -Insert before 2b
  +insert before 2b
  $ hg annotate a
  1: Insert before 2b
  1: 2b
  2: 4d
  2: insert aftert 4d

Make working copy clean:

  $ hg revert -q -C a b
  $ hg forget c
  $ rm c
  $ hg status

Merge commit will not be changed:

  $ echo 1 > m1
  $ hg commit -A m1 -m m1
  $ hg bookmark -q -i m1
  $ hg update -q '.^'
  $ echo 2 > m2
  $ hg commit -q -A m2 -m m2
  $ hg merge -q m1
  $ hg commit -m merge
  $ hg bookmark -d m1
  $ hg log -G -T '{rev} {desc} {phase}\n'
  @    6 merge draft
  |\
  | o  5 m2 draft
  | |
  o |  4 m1 draft
  |/
  o  3 b draft
  |
  o  2 commit 4 draft
  |
  o  1 commit 2 public
  |
  o  0 commit 1 public
  
  $ echo 2 >> m1
  $ echo 2 >> m2
  $ hg absorb --apply-changes
  abort: no mutable changeset to change
  [255]
  $ hg revert -q -C m1 m2

Use a new repo:

  $ cd ..
  $ hg init repo2
  $ cd repo2

Make some commits to multiple files:

  $ for f in a b; do
  >   for i in 1 2; do
  >     echo $f line $i >> $f
  >     hg commit -A $f -m "commit $f $i" -q
  >   done
  > done

Use pattern to select files to be fixed up:

  $ sedi 's/line/Line/' a b
  $ hg status
  M a
  M b
  $ hg absorb --apply-changes a
  saved backup bundle to * (glob)
  1 of 1 chunk(s) applied
  $ hg status
  M b
  $ hg absorb --apply-changes --exclude b
  nothing applied
  [1]
  $ hg absorb --apply-changes b
  saved backup bundle to * (glob)
  1 of 1 chunk(s) applied
  $ hg status
  $ cat a b
  a Line 1
  a Line 2
  b Line 1
  b Line 2

Test config option absorb.max-stack-size:

  $ sedi 's/Line/line/' a b
  $ hg log -T '{rev}:{node} {desc}\n'
  3:712d16a8f445834e36145408eabc1d29df05ec09 commit b 2
  2:74cfa6294160149d60adbf7582b99ce37a4597ec commit b 1
  1:28f10dcf96158f84985358a2e5d5b3505ca69c22 commit a 2
  0:f9a81da8dc53380ed91902e5b82c1b36255a4bd0 commit a 1
  $ hg --config absorb.max-stack-size=1 absorb -pn
  absorb: only the recent 1 changesets will be analysed
  showing changes for a
          @@ -0,2 +0,2 @@
          -a Line 1
          -a Line 2
          +a line 1
          +a line 2
  showing changes for b
          @@ -0,2 +0,2 @@
          -b Line 1
  712d16a -b Line 2
          +b line 1
  712d16a +b line 2
  
  1 changesets affected
  712d16a commit b 2

Test obsolete markers creation:

  $ cat >> $HGRCPATH << EOF
  > [experimental]
  > evolution=createmarkers
  > [absorb]
  > add-noise=1
  > EOF

  $ hg --config absorb.max-stack-size=3 absorb -a
  absorb: only the recent 3 changesets will be analysed
  2 of 2 chunk(s) applied
  $ hg log -T '{rev}:{node|short} {desc} {get(extras, "absorb_source")}\n'
  6:3dfde4199b46 commit b 2 712d16a8f445834e36145408eabc1d29df05ec09
  5:99cfab7da5ff commit b 1 74cfa6294160149d60adbf7582b99ce37a4597ec
  4:fec2b3bd9e08 commit a 2 28f10dcf96158f84985358a2e5d5b3505ca69c22
  0:f9a81da8dc53 commit a 1 
  $ hg absorb --apply-changes
  1 of 1 chunk(s) applied
  $ hg log -T '{rev}:{node|short} {desc} {get(extras, "absorb_source")}\n'
  10:e1c8c1e030a4 commit b 2 3dfde4199b4610ea6e3c6fa9f5bdad8939d69524
  9:816c30955758 commit b 1 99cfab7da5ffdaf3b9fc6643b14333e194d87f46
  8:5867d584106b commit a 2 fec2b3bd9e0834b7cb6a564348a0058171aed811
  7:8c76602baf10 commit a 1 f9a81da8dc53380ed91902e5b82c1b36255a4bd0

Executable files:

  $ cat >> $HGRCPATH << EOF
  > [diff]
  > git=True
  > EOF
  $ cd ..
  $ hg init repo3
  $ cd repo3

#if execbit
  $ echo > foo.py
  $ chmod +x foo.py
  $ hg add foo.py
  $ hg commit -mfoo
#else
  $ hg import -q --bypass - <<EOF
  > # HG changeset patch
  > foo
  > 
  > diff --git a/foo.py b/foo.py
  > new file mode 100755
  > --- /dev/null
  > +++ b/foo.py
  > @@ -0,0 +1,1 @@
  > +
  > EOF
  $ hg up -q
#endif

  $ echo bla > foo.py
  $ hg absorb --dry-run --print-changes
  showing changes for foo.py
          @@ -0,1 +0,1 @@
  99b4ae7 -
  99b4ae7 +bla
  
  1 changesets affected
  99b4ae7 foo
  $ hg absorb --apply-changes
  1 of 1 chunk(s) applied
  $ hg diff -c .
  diff --git a/foo.py b/foo.py
  new file mode 100755
  --- /dev/null
  +++ b/foo.py
  @@ -0,0 +1,1 @@
  +bla
  $ hg diff

Remove lines may delete changesets:

  $ cd ..
  $ hg init repo4
  $ cd repo4
  $ cat > a <<EOF
  > 1
  > 2
  > EOF
  $ hg commit -m a12 -A a
  $ cat > b <<EOF
  > 1
  > 2
  > EOF
  $ hg commit -m b12 -A b
  $ echo 3 >> b
  $ hg commit -m b3
  $ echo 4 >> b
  $ hg commit -m b4
  $ echo 1 > b
  $ echo 3 >> a
  $ hg absorb -pn
  showing changes for a
          @@ -2,0 +2,1 @@
  bfafb49 +3
  showing changes for b
          @@ -1,3 +1,0 @@
  1154859 -2
  30970db -3
  a393a58 -4
  
  4 changesets affected
  a393a58 b4
  30970db b3
  1154859 b12
  bfafb49 a12
  $ hg absorb -av | grep became
  0:bfafb49242db: 1 file(s) changed, became 4:1a2de97fc652
  1:115485984805: 2 file(s) changed, became 5:0c930dfab74c
  2:30970dbf7b40: became empty and was dropped
  3:a393a58b9a85: became empty and was dropped
  $ hg log -T '{rev} {desc}\n' -Gp
  @  5 b12
  |  diff --git a/b b/b
  |  new file mode 100644
  |  --- /dev/null
  |  +++ b/b
  |  @@ -0,0 +1,1 @@
  |  +1
  |
  o  4 a12
     diff --git a/a b/a
     new file mode 100644
     --- /dev/null
     +++ b/a
     @@ -0,0 +1,3 @@
     +1
     +2
     +3
  

Use revert to make the current change and its parent disappear.
This should move us to the non-obsolete ancestor.

  $ cd ..
  $ hg init repo5
  $ cd repo5
  $ cat > a <<EOF
  > 1
  > 2
  > EOF
  $ hg commit -m a12 -A a
  $ hg id
  bfafb49242db tip
  $ echo 3 >> a
  $ hg commit -m a123 a
  $ echo 4 >> a
  $ hg commit -m a1234 a
  $ hg id
  82dbe7fd19f0 tip
  $ hg revert -r 0 a
  $ hg absorb -pn
  showing changes for a
          @@ -2,2 +2,0 @@
  f1c23dd -3
  82dbe7f -4
  
  2 changesets affected
  82dbe7f a1234
  f1c23dd a123
  $ hg absorb --apply-changes --verbose
  1:f1c23dd5d08d: became empty and was dropped
  2:82dbe7fd19f0: became empty and was dropped
  a: 1 of 1 chunk(s) applied
  $ hg id
  bfafb49242db tip