dirstate-tree: Add tree traversal/iteration
Like Python’s, Rust’s iterators are "external" in that they are driven
by a caller who calls a `next` method. This is as opposed to "internal"
iterators who drive themselves and call a callback for each item.
Writing an internal iterator traversing a tree is easy with recursion,
but internal iterators cannot rely on the call stack in that way,
they must save in an explicit object all state that they need to be
preserved across two `next` calls.
This algorithm uses a `Vec` as a stack that contains what would be
local variables on the call stack if we could use recursion.
Differential Revision: https://phab.mercurial-scm.org/D10370
#require no-reposimplestore
Test unionrepo functionality
Create one repository
$ hg init repo1
$ cd repo1
$ touch repo1-0
$ echo repo1-0 > f
$ hg ci -Aqmrepo1-0
$ touch repo1-1
$ echo repo1-1 >> f
$ hg ci -Aqmrepo1-1
$ touch repo1-2
$ echo repo1-2 >> f
$ hg ci -Aqmrepo1-2
$ hg log --template '{rev}:{node|short} {desc|firstline}\n'
2:68c0685446a3 repo1-2
1:8a58db72e69d repo1-1
0:f093fec0529b repo1-0
$ tip1=`hg id -q`
$ cd ..
- and a clone with a not-completely-trivial history
$ hg clone -q repo1 --rev 0 repo2
$ cd repo2
$ touch repo2-1
$ sed '1i\
> repo2-1 at top
> ' f > f.tmp
$ mv f.tmp f
$ hg ci -Aqmrepo2-1
$ touch repo2-2
$ hg pull -q ../repo1 -r 1
$ hg merge -q
$ hg ci -Aqmrepo2-2-merge
$ touch repo2-3
$ echo repo2-3 >> f
$ hg ci -mrepo2-3
$ hg log --template '{rev}:{node|short} {desc|firstline}\n'
4:2f0d178c469c repo2-3
3:9e6fb3e0b9da repo2-2-merge
2:8a58db72e69d repo1-1
1:c337dba826e7 repo2-1
0:f093fec0529b repo1-0
$ cd ..
revisions from repo2 appear as appended / pulled to repo1
$ hg -R union:repo1+repo2 log --template '{rev}:{node|short} {desc|firstline}\n'
5:2f0d178c469c repo2-3
4:9e6fb3e0b9da repo2-2-merge
3:c337dba826e7 repo2-1
2:68c0685446a3 repo1-2
1:8a58db72e69d repo1-1
0:f093fec0529b repo1-0
manifest can be retrieved for revisions in both repos
$ hg -R union:repo1+repo2 mani -r $tip1
f
repo1-0
repo1-1
repo1-2
$ hg -R union:repo1+repo2 mani -r 4
f
repo1-0
repo1-1
repo2-1
repo2-2
files can be retrieved form both repos
$ hg -R repo1 cat repo1/f -r2
repo1-0
repo1-1
repo1-2
$ hg -R union:repo1+repo2 cat -r$tip1 repo1/f
repo1-0
repo1-1
repo1-2
$ hg -R union:repo1+repo2 cat -r4 $TESTTMP/repo1/f
repo2-1 at top
repo1-0
repo1-1
files can be compared across repos
$ hg -R union:repo1+repo2 diff -r$tip1 -rtip
diff -r 68c0685446a3 -r 2f0d178c469c f
--- a/f Thu Jan 01 00:00:00 1970 +0000
+++ b/f Thu Jan 01 00:00:00 1970 +0000
@@ -1,3 +1,4 @@
+repo2-1 at top
repo1-0
repo1-1
-repo1-2
+repo2-3
heads from both repos are found correctly
$ hg -R union:repo1+repo2 heads --template '{rev}:{node|short} {desc|firstline}\n'
5:2f0d178c469c repo2-3
2:68c0685446a3 repo1-2
revsets works across repos
$ hg -R union:repo1+repo2 id -r "ancestor($tip1, 5)"
8a58db72e69d
annotate works - an indication that linkrevs works
$ hg --cwd repo1 -Runion:../repo2 annotate $TESTTMP/repo1/f -r tip
3: repo2-1 at top
0: repo1-0
1: repo1-1
5: repo2-3
union repos can be cloned ... and clones works correctly
$ hg clone -U union:repo1+repo2 repo3
requesting all changes
adding changesets
adding manifests
adding file changes
added 6 changesets with 11 changes to 6 files (+1 heads)
new changesets f093fec0529b:2f0d178c469c (6 drafts)
$ hg -R repo3 paths
default = union:repo1+repo2
$ hg -R repo3 verify
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
checked 6 changesets with 11 changes to 6 files
$ hg -R repo3 heads --template '{rev}:{node|short} {desc|firstline}\n'
5:2f0d178c469c repo2-3
2:68c0685446a3 repo1-2
$ hg -R repo3 log --template '{rev}:{node|short} {desc|firstline}\n'
5:2f0d178c469c repo2-3
4:9e6fb3e0b9da repo2-2-merge
3:c337dba826e7 repo2-1
2:68c0685446a3 repo1-2
1:8a58db72e69d repo1-1
0:f093fec0529b repo1-0
union repos should use the correct rev number (issue5024)
$ hg init a
$ cd a
$ echo a0 >> f
$ hg ci -Aqm a0
$ cd ..
$ hg init b
$ cd b
$ echo b0 >> f
$ hg ci -Aqm b0
$ echo b1 >> f
$ hg ci -qm b1
$ cd ..
"hg files -v" to call fctx.size() -> fctx.iscensored()
$ hg files -R union:b+a -r2 -v
3 b/f