branchcache: add a "pure topological head" fast path
In a narrow but actually quick common case, all topological heads are all on
the same branch and all open. In this case, computing the branch map is very
simple. We can quickly detect situation where this situation will not change.
So we update the V3 format to be able to express this situation and upgrade the
update code to detect we remains in that mode.
The branch cache is populated with the actual value when the branch map is
accessed, but the update_disk method can do the update without needing to
populate it.
$ hg init
$ mkdir d1 d1/d11 d2
$ echo d1/a > d1/a
$ echo d1/ba > d1/ba
$ echo d1/a1 > d1/d11/a1
$ echo d1/b > d1/b
$ echo d2/b > d2/b
$ hg add d1/a d1/b d1/ba d1/d11/a1 d2/b
$ hg commit -m "intial"
Test single file
# One recorded copy, one copy to record after commit
$ hg cp d1/b d1/c
$ cp d1/b d1/d
$ hg add d1/d
$ hg ci -m 'copy d1/b to d1/c and d1/d'
$ hg st -C --change .
A d1/c
d1/b
A d1/d
# Errors out without --after for now
$ hg cp --at-rev . d1/b d1/d
abort: --at-rev requires --after
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# Errors out with non-existent source
$ hg cp -A --at-rev . d1/non-existent d1/d
d1/non-existent: no such file in rev 55d1fd85ef0a
abort: no files to copy
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# Errors out with non-existent destination
$ hg cp -A --at-rev . d1/b d1/non-existent
abort: d1/non-existent: copy destination does not exist in 8a9d70fa20c9
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# Successful invocation
$ hg cp -A --at-rev . d1/b d1/d
saved backup bundle to $TESTTMP/.hg/strip-backup/8a9d70fa20c9-973ae357-copy.hg
# New copy is recorded, and previously recorded copy is also still there
$ hg st -C --change .
A d1/c
d1/b
A d1/d
d1/b
# Should get helpful message if we try to copy or rename after commit
$ hg cp --forget --at-rev . d1/d
saved backup bundle to $TESTTMP/.hg/strip-backup/3f7c325d3f9e-46f377bb-uncopy.hg
$ hg cp d1/b d1/d
d1/d: not overwriting - file already committed
('hg copy --at-rev .' to record the copy in the parent of the working copy)
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$ hg mv d1/b d1/d
d1/d: not overwriting - file already committed
('hg rename --at-rev .' to record the rename in the parent of the working copy)
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Test moved file (not copied) using 'hg cp' command
$ hg co 0
0 files updated, 0 files merged, 2 files removed, 0 files unresolved
$ mv d1/b d1/d
$ hg rm -A d1/b
$ hg add d1/d
$ hg ci -m 'move d1/b to d1/d'
created new head
$ hg cp -A --at-rev . d1/b d1/d
saved backup bundle to $TESTTMP/.hg/strip-backup/519850c3ea27-153c8fbb-copy.hg
$ hg st -C --change .
A d1/d
d1/b
R d1/b
Test moved file (not copied) using 'hg mv' command
$ hg co 0
1 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ mv d1/b d1/d
$ hg rm -A d1/b
$ hg add d1/d
$ hg ci -m 'move d1/b to d1/d'
created new head
$ hg mv -A --at-rev . d1/b d1/d
saved backup bundle to $TESTTMP/.hg/strip-backup/519850c3ea27-153c8fbb-copy.hg
$ hg st -C --change .
A d1/d
d1/b
R d1/b
Test moved file (not copied) for which source still exists
$ hg co 0
1 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ cp d1/b d1/d
$ hg add d1/d
$ hg ci -m 'copy d1/b to d1/d'
created new head
$ hg mv -A --at-rev . d1/b d1/d
saved backup bundle to $TESTTMP/.hg/strip-backup/c8d0f6bcf7ca-1c9bb53e-copy.hg
$ hg st -C --change .
A d1/d
d1/b
Test using directory as destination
$ hg co 0
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ cp -R d1 d3
$ hg add d3
adding d3/a
adding d3/b
adding d3/ba
adding d3/d11/a1
$ hg ci -m 'copy d1/ to d3/'
created new head
$ hg cp -A --at-rev . d1 d3
abort: d3: --at-rev does not support a directory as destination
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