view tests/test-narrow-strip.t @ 48507:58a3be48ddd2

simplemerge: stop merging file flags

As 384df4db6520 (merge: merge file flags together with file content,
2013-01-09) explains, we shouldn't do a 3-way merge of the
symlink. However, since 84614212ae39 (flags: actually merge flags in
simplemerge, 2020-05-16), we do that in
`simplemerge.simplemerge()`. What's more, the merging of the
executable flag there isn't actually necessary; it was made a no-op by
the very next commit, i.e. 4234c9af515d (flags: read flag from
dirstate/disk for workingcopyctx (issue5743), 2020-05-16).

I found the overall flag-merging code (not the bit in
`simplemerge.py`) very hard to follow, but I think I now finally
understand how it works. `mergestate.resolve()` calculates the merged
file flags and sets them on the local side of the merge (confusingly
by calling `_restore_backup()`). Then it calls
`filemerge.filemerge()`, which in turn calls
`simplemerge.simplemerge()` (if premerge is enabled). That means that
the flags on the local side `fcs.flags()` are already correct when the
flag-merging code in `simplemerge.simplemerge()` runs. Interestingly,
that code still works when the local side already has the merged
value, it just doesn't change the value. Here's a truth table to
explain why:

```
BLOMCAR
0000000
0011111
0101011
0111111
1000000
1010000
1100000
1111101
```

B: Base
L: Local
O: Other
M: Merged flags from `mergestate.resolve()`, i.e. what's called "local"
   when we get to `simplemerge.simplemerge()`
C: `commonflags` in `simplemerge.simplemerge()`, i.e. `M & O`
A: `addedflags` in `simplemerge.simplemerge()`, i.e. `(M ^ O) - B`
R: Re-merged flags `simplemerge.simplemerge()`, i.e. `C | A`

As you can see, the re-merged flags are always unchanged compared to
the initial merged flags (R equals M).

Therefore, this patch effectively backs out 84614212ae39. (I might
later refactor this code to have the flags explicitly passed in.)

`simplemerge.simplemerge()` is also called from
`contrib/simplemerge.py`, but that code never passes any flags.

Differential Revision: https://phab.mercurial-scm.org/D11879

#testcases flat tree
#testcases lfs-on lfs-off

#if lfs-on
  $ cat >> $HGRCPATH <<EOF
  > [extensions]
  > lfs =
  > EOF
#endif

  $ . "$TESTDIR/narrow-library.sh"

#if tree
  $ cat << EOF >> $HGRCPATH
  > [experimental]
  > treemanifest = 1
  > EOF
#endif

create full repo

  $ hg init master
  $ cd master
  $ cat >> .hg/hgrc <<EOF
  > [narrow]
  > serveellipses=True
  > EOF

  $ mkdir inside
  $ echo inside > inside/f1
  $ mkdir outside
  $ echo outside > outside/f1
  $ hg ci -Aqm 'initial'

  $ echo modified > inside/f1
  $ hg ci -qm 'modify inside'

  $ hg co -q 0
  $ echo modified > outside/f1
  $ hg ci -qm 'modify outside'

  $ echo modified again >> outside/f1
  $ hg ci -qm 'modify outside again'

  $ cd ..

  $ hg clone --narrow ssh://user@dummy/master narrow --include inside
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 3 changesets with 2 changes to 1 files (+1 heads)
  new changesets *:* (glob)
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd narrow
  $ cat >> $HGRCPATH <<EOF
  > [extensions]
  > strip=
  > EOF

Can strip and recover changesets affecting only files within narrow spec

  $ hg co -r 'desc("modify inside")'
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ rm -f .hg/strip-backup/*-backup.hg
  $ hg strip .
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  saved backup bundle to $TESTTMP/narrow/.hg/strip-backup/*-backup.hg (glob)
  $ hg unbundle .hg/strip-backup/*-backup.hg
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files (+1 heads)
  new changesets * (glob)
  (run 'hg heads' to see heads, 'hg merge' to merge)

Can strip and recover changesets affecting files outside of narrow spec

  $ hg co -r 'desc("modify outside")'
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg log -G -T '{rev} {desc}\n'
  o  2 modify inside
  |
  | @  1 modify outside again
  |/
  o  0 initial
  
  $ hg debugdata -m 1
  inside/f1\x004d6a634d5ba06331a60c29ee0db8412490a54fcd (esc) (flat !)
  outside/f1\x0084ba604d54dee1f13310ce3d4ac2e8a36636691a (esc) (flat !)
  inside\x006a8bc41df94075d501f9740587a0c0e13c170dc5t (esc) (tree !)
  outside\x00255c2627ebdd3c7dcaa6945246f9b9f02bd45a09t (esc) (tree !)

  $ rm -f .hg/strip-backup/*-backup.hg
  $ hg strip .
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  saved backup bundle to $TESTTMP/narrow/.hg/strip-backup/*-backup.hg (glob)
  $ hg unbundle .hg/strip-backup/*-backup.hg
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 0 changes to 0 files (+1 heads)
  new changesets * (glob)
  (run 'hg heads' to see heads, 'hg merge' to merge)
  $ hg log -G -T '{rev} {desc}\n'
  o  2 modify outside again
  |
  | o  1 modify inside
  |/
  @  0 initial
  
Check that hash of file outside narrow spec got restored
  $ hg debugdata -m 2
  inside/f1\x004d6a634d5ba06331a60c29ee0db8412490a54fcd (esc) (flat !)
  outside/f1\x0084ba604d54dee1f13310ce3d4ac2e8a36636691a (esc) (flat !)
  inside\x006a8bc41df94075d501f9740587a0c0e13c170dc5t (esc) (tree !)
  outside\x00255c2627ebdd3c7dcaa6945246f9b9f02bd45a09t (esc) (tree !)

Also verify we can apply the bundle with 'hg pull':
  $ hg co -r 'desc("modify inside")'
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ rm .hg/strip-backup/*-backup.hg
  $ hg strip .
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  saved backup bundle to $TESTTMP/narrow/.hg/strip-backup/*-backup.hg (glob)
#if repobundlerepo
  $ hg pull .hg/strip-backup/*-backup.hg
  pulling from .hg/strip-backup/*-backup.hg (glob)
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files (+1 heads)
  new changesets * (glob)
  (run 'hg heads' to see heads, 'hg merge' to merge)

  $ rm .hg/strip-backup/*-backup.hg
  $ hg strip 0
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  saved backup bundle to $TESTTMP/narrow/.hg/strip-backup/*-backup.hg (glob)

  $ hg incoming .hg/strip-backup/*-backup.hg
  comparing with .hg/strip-backup/*-backup.hg (glob)
  changeset:   0:* (glob)
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     initial
  
  changeset:   1:9e48d953700d (flat !)
  changeset:   1:3888164bccf0 (tree !)
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     modify outside again
  
  changeset:   2:f505d5e96aa8 (flat !)
  changeset:   2:40b66f95a209 (tree !)
  tag:         tip
  parent:      0:a99f4d53924d (flat !)
  parent:      0:c2a5fabcca3c (tree !)
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     modify inside
  
  $ hg pull .hg/strip-backup/*-backup.hg
  pulling from .hg/strip-backup/*-backup.hg (glob)
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 3 changesets with 2 changes to 1 files (+1 heads)
  new changesets *:* (glob)
  (run 'hg heads' to see heads, 'hg merge' to merge)
#endif