view tests/test-merge-no-file-change.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

  $ cat <<'EOF' >> "$HGRCPATH"
  > [extensions]
  > convert =
  > [templates]
  > l = '{rev}:{node|short} p={p1rev},{p2rev} m={manifest} f={files|json}'
  > EOF

  $ check_convert_identity () {
  >     hg convert -q "$1" "$1.converted"
  >     hg outgoing -q -R "$1.converted" "$1"
  >     if [ "$?" != 1 ]; then
  >         echo '*** BUG: hash changes on convert ***'
  >         hg log -R "$1.converted" -GTl
  >     fi
  > }

Files added at both parents:

  $ hg init added-both
  $ cd added-both
  $ touch a b c
  $ hg ci -qAm0 a
  $ hg ci -qAm1 b
  $ hg up -q 0
  $ hg ci -qAm2 c

  $ hg merge
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg ci --debug -m merge
  committing files:
  b
  not reusing manifest (no file change in changelog, but manifest differs)
  committing manifest
  committing changelog
  updating the branch cache
  committed changeset 3:7aa8a293f5d97377037afc21e871e036e718d659
  $ hg log -GTl
  @    3:7aa8a293f5d9 p=2,1 m=3:8667461869a1 f=[]
  |\
  | o  2:e0ea47086fce p=0,-1 m=2:b2e5b07f9374 f=["c"]
  | |
  o |  1:64d01526d4c2 p=0,-1 m=1:686dbf0aeca4 f=["b"]
  |/
  o  0:487a0a245cea p=-1,-1 m=0:8515d4bfda76 f=["a"]
  

  $ cd ..
  $ check_convert_identity added-both

Files added at both parents, but the other removed at the merge:
(In this case, ctx.files() after the commit contains the removed file "b", but
its manifest does not differ from p1.)

  $ hg init added-both-removed-at-merge
  $ cd added-both-removed-at-merge
  $ touch a b c
  $ hg ci -qAm0 a
  $ hg ci -qAm1 b
  $ hg up -q 0
  $ hg ci -qAm2 c

  $ hg merge
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg rm -f b
  $ hg ci --debug -m merge
  committing files:
  committing manifest
  committing changelog
  updating the branch cache
  committed changeset 3:915745f3ca3d9d699925269474c2d0a9526e8dfa
  $ hg log -GTl
  @    3:915745f3ca3d p=2,1 m=3:8e9cf3456921 f=["b"]
  |\
  | o  2:e0ea47086fce p=0,-1 m=2:b2e5b07f9374 f=["c"]
  | |
  o |  1:64d01526d4c2 p=0,-1 m=1:686dbf0aeca4 f=["b"]
  |/
  o  0:487a0a245cea p=-1,-1 m=0:8515d4bfda76 f=["a"]
  

  $ cd ..
  $ check_convert_identity added-both

An identical file added at both parents:

  $ hg init added-identical
  $ cd added-identical
  $ touch a b
  $ hg ci -qAm0 a
  $ hg ci -qAm1 b
  $ hg up -q 0
  $ touch b
  $ hg ci -qAm2 b

  $ hg merge
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg ci --debug -m merge
  reusing manifest from p1 (no file change)
  committing changelog
  updating the branch cache
  committed changeset 3:de26182cd210f0c3fb175ca7616704ab963d3024
  $ hg log -GTl
  @    3:de26182cd210 p=2,1 m=1:686dbf0aeca4 f=[]
  |\
  | o  2:f00991f11eca p=0,-1 m=1:686dbf0aeca4 f=["b"]
  | |
  o |  1:64d01526d4c2 p=0,-1 m=1:686dbf0aeca4 f=["b"]
  |/
  o  0:487a0a245cea p=-1,-1 m=0:8515d4bfda76 f=["a"]
  

  $ cd ..
  $ check_convert_identity added-identical

#if execbit

An identical file added at both parents, but the flag differs. Take local:

  $ hg init flag-change-take-p1
  $ cd flag-change-take-p1
  $ touch a b
  $ hg ci -qAm0 a
  $ hg ci -qAm1 b
  $ hg up -q 0
  $ touch b
  $ chmod +x b
  $ hg ci -qAm2 b

  $ hg merge
  warning: cannot merge flags for b without common ancestor - keeping local flags
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ chmod +x b
  $ hg ci --debug -m merge
  committing files:
  b
  reusing manifest from p1 (listed files actually unchanged)
  committing changelog
  updating the branch cache
  committed changeset 3:c8d50407916ef8a5a97cb6e36ca9bc844a6ee13e
  $ hg log -GTl
  @    3:c8d50407916e p=2,1 m=2:36b69ba4b24b f=[]
  |\
  | o  2:99451f16b3f5 p=0,-1 m=2:36b69ba4b24b f=["b"]
  | |
  o |  1:64d01526d4c2 p=0,-1 m=1:686dbf0aeca4 f=["b"]
  |/
  o  0:487a0a245cea p=-1,-1 m=0:8515d4bfda76 f=["a"]
  
  $ hg files -vr3
           0   a
           0 x b

  $ cd ..
  $ check_convert_identity flag-change-take-p1

An identical file added at both parents, but the flag differs. Take other:

  $ hg init flag-change-take-p2
  $ cd flag-change-take-p2
  $ touch a b
  $ hg ci -qAm0 a
  $ hg ci -qAm1 b
  $ hg up -q 0
  $ touch b
  $ chmod +x b
  $ hg ci -qAm2 b

  $ hg merge
  warning: cannot merge flags for b without common ancestor - keeping local flags
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ chmod -x b
  $ hg ci --debug -m merge
  committing files:
  b
  committing manifest
  committing changelog
  updating the branch cache
  committed changeset 3:06a62a687d87c7d8944743dee1ee9d8c66b3f6e3
  $ hg log -GTl
  @    3:06a62a687d87 p=2,1 m=3:2a315ba1aa45 f=["b"]
  |\
  | o  2:99451f16b3f5 p=0,-1 m=2:36b69ba4b24b f=["b"]
  | |
  o |  1:64d01526d4c2 p=0,-1 m=1:686dbf0aeca4 f=["b"]
  |/
  o  0:487a0a245cea p=-1,-1 m=0:8515d4bfda76 f=["a"]
  
  $ hg files -vr3
           0   a
           0   b

  $ cd ..
  $ check_convert_identity flag-change-take-p2

#endif

An identical file added at both parents, one more file added at p2:

  $ hg init added-some-p2
  $ cd added-some-p2
  $ touch a b c
  $ hg ci -qAm0 a
  $ hg ci -qAm1 b
  $ hg ci -qAm2 c
  $ hg up -q 0
  $ touch b
  $ hg ci -qAm3 b

  $ hg merge
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg ci --debug -m merge
  committing files:
  c
  not reusing manifest (no file change in changelog, but manifest differs)
  committing manifest
  committing changelog
  updating the branch cache
  committed changeset 4:f7fbc4e4d9a8fde03ba475adad675578c8bf472d
  $ hg log -GTl
  @    4:f7fbc4e4d9a8 p=3,2 m=3:92acd5bfd716 f=[]
  |\
  | o  3:e9d9f3cc981f p=0,-1 m=1:686dbf0aeca4 f=["b"]
  | |
  o |  2:93c5529a4ec7 p=1,-1 m=2:ae25a31b30b3 f=["c"]
  | |
  o |  1:64d01526d4c2 p=0,-1 m=1:686dbf0aeca4 f=["b"]
  |/
  o  0:487a0a245cea p=-1,-1 m=0:8515d4bfda76 f=["a"]
  

  $ cd ..
  $ check_convert_identity added-some-p2

An identical file added at both parents, one more file added at p1:
(In this case, p1 manifest is reused at the merge commit, which means the
manifest DAG does not have the same shape as the changelog.)

  $ hg init added-some-p1
  $ cd added-some-p1
  $ touch a b
  $ hg ci -qAm0 a
  $ hg ci -qAm1 b
  $ hg up -q 0
  $ touch b c
  $ hg ci -qAm2 b
  $ hg ci -qAm3 c

  $ hg merge
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg ci --debug -m merge
  reusing manifest from p1 (no file change)
  committing changelog
  updating the branch cache
  committed changeset 4:a9f0f589a913f5a149dc10dfbd5af726977c36c4
  $ hg log -GTl
  @    4:a9f0f589a913 p=3,1 m=2:ae25a31b30b3 f=[]
  |\
  | o  3:b8dc385241b5 p=2,-1 m=2:ae25a31b30b3 f=["c"]
  | |
  | o  2:f00991f11eca p=0,-1 m=1:686dbf0aeca4 f=["b"]
  | |
  o |  1:64d01526d4c2 p=0,-1 m=1:686dbf0aeca4 f=["b"]
  |/
  o  0:487a0a245cea p=-1,-1 m=0:8515d4bfda76 f=["a"]
  

  $ cd ..
  $ check_convert_identity added-some-p1

A file added at p2, a named branch created at p1:

  $ hg init named-branch-p1
  $ cd named-branch-p1
  $ touch a b
  $ hg ci -qAm0 a
  $ hg ci -qAm1 b
  $ hg up -q 0
  $ hg branch -q foo
  $ hg ci -m2

  $ hg merge default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg ci --debug -m merge
  committing files:
  b
  not reusing manifest (no file change in changelog, but manifest differs)
  committing manifest
  committing changelog
  updating the branch cache
  committed changeset 3:fb97d83b02fd072295cfc2171f21b7d38509bfd7
  $ hg log -GT'{l} branch={branch}'
  @    3:fb97d83b02fd p=2,1 m=2:9091c64f4ea1 f=[] branch=foo
  |\
  | o  2:a3a9fa6587e5 p=0,-1 m=0:8515d4bfda76 f=[] branch=foo
  | |
  o |  1:64d01526d4c2 p=0,-1 m=1:686dbf0aeca4 f=["b"] branch=default
  |/
  o  0:487a0a245cea p=-1,-1 m=0:8515d4bfda76 f=["a"] branch=default
  

  $ cd ..
  $ check_convert_identity named-branch-p1

A file added at p1, a named branch created at p2:
(In this case, p1 manifest is reused at the merge commit, which means the
manifest DAG does not have the same shape as the changelog.)

  $ hg init named-branch-p2
  $ cd named-branch-p2
  $ touch a b
  $ hg ci -qAm0 a
  $ hg branch -q foo
  $ hg ci -m1
  $ hg up -q 0
  $ hg ci -qAm1 b

  $ hg merge foo
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg ci --debug -m merge
  reusing manifest from p1 (no file change)
  committing changelog
  updating the branch cache
  committed changeset 3:036823e24692218324d4af43b07ff89f8a000096
  $ hg log -GT'{l} branch={branch}'
  @    3:036823e24692 p=2,1 m=1:686dbf0aeca4 f=[] branch=default
  |\
  | o  2:64d01526d4c2 p=0,-1 m=1:686dbf0aeca4 f=["b"] branch=default
  | |
  o |  1:da38c8e00727 p=0,-1 m=0:8515d4bfda76 f=[] branch=foo
  |/
  o  0:487a0a245cea p=-1,-1 m=0:8515d4bfda76 f=["a"] branch=default
  

  $ cd ..
  $ check_convert_identity named-branch-p2

A file changed once at both parents, but amended to have identical content:

  $ hg init amend-p1
  $ cd amend-p1
  $ touch a
  $ hg ci -qAm0 a
  $ echo foo > a
  $ hg ci -m1
  $ hg up -q 0
  $ echo bar > a
  $ hg ci -qm2
  $ echo foo > a
  $ hg ci -qm3 --amend

  $ hg merge
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg ci --debug -m merge
  reusing manifest from p1 (no file change)
  committing changelog
  updating the branch cache
  committed changeset 3:314e5bc5adf5c58ea571efabe33eedba20a201aa
  $ hg log -GT'{l} branch={branch}'
  @    3:314e5bc5adf5 p=2,1 m=1:d33ea248bd73 f=[] branch=default
  |\
  | o  2:de9c64f226a3 p=0,-1 m=1:d33ea248bd73 f=["a"] branch=default
  | |
  o |  1:6a74aec01b3c p=0,-1 m=1:d33ea248bd73 f=["a"] branch=default
  |/
  o  0:487a0a245cea p=-1,-1 m=0:8515d4bfda76 f=["a"] branch=default
  

  $ cd ..
  $ check_convert_identity amend-p1