view tests/test-merge-no-file-change.t @ 40393:229d23cdb203

exchangev2: support fetching shallow files history

This commit teaches the exchangev2 client code to handle fetching shallow
files data.

Only shallow fetching of files data is supported: shallow fetching of
changeset and manifest data is explicitly not yet supported.

Previously, we would fetch file revisions for changesets that were received
by the current pull operation. In the new model, we calculate the set of
"relevant" changesets given the pull depth and only fetch files data for
those changesets.

We also teach the "filesdata" command invocation to vary parameters as needed.

The implementation here is far from complete or optimal. Subsequent pulls will
end up re-fetching a lot of files data. But the application of this data should
mostly be a no-op on the client, so it isn't a big deal.

Depending on the order file revisions are fetched in, revisions could get
inserted with the wrong revision number relationships. I think the best way
to deal with this is to remove revision numbers from storage and to either
dynamically derive them (by reconstructing a DAG from nodes/parents) or remove
revision numbers from the file storage interface completely.

A missing API that we'll likely want to write pretty soon is "ensure files
for revision(s) are present." We can kind of cajole exchangev2.pull() to do
this. But it isn't very efficient. For example, in simple cases like
widening the store to obtain data for a single revision, it is probably
more efficient to walk the manifest and find exactly which file revisions
are missing and to make explicit requests for just their data. In more
advanced cases, asking the server for all files data may be more efficient,
even though it requires sending data the client already has. There is tons
of room for future experimentation here. And TBH I'm not sure what the
final state will be.

Anyway, this commit gets us pretty close to being able to have shallow
and narrow checkouts with exchangev2/sqlite storage. Close enough that a
minimal extension should be able to provide fill in the gaps until the code
in core stabilizes and there is a user-facing way to trigger the
narrow/shallow bits from `hg clone` without also implying using of the
narrow extension...

Differential Revision: https://phab.mercurial-scm.org/D5169

  $ 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 form 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