bundle2: extract logic for seeking bundle2 part into own class
Currently, unbundlepart classes support bi-directional seeking.
Most consumers of unbundlepart only ever seek forward - typically
as part of moving to the end of the bundle part so they can move
on to the next one. But regardless of the actual usage of the
part, instances maintain an index mapping offsets within the
underlying raw payload to offsets within the decoded payload.
Maintaining the mapping of offset data can be expensive in terms of
memory use. Furthermore, many bundle2 consumers don't have access
to an underlying seekable stream. This includes all compressed
bundles. So maintaining offset data when the underlying stream
can't be seeked anyway is wasteful. And since many bundle2 streams
can't be seeked, it seems like a bad idea to expose a seek API
in bundle2 parts by default. If you provide them, people will
attempt to use them.
Seekable bundle2 parts should be the exception, not the rule. This
commit starts the process dividing unbundlepart into 2 classes: a
base class that supports linear, one-time reads and a child class
that supports bi-directional seeking. In this first commit, we
split various methods and attributes out into a new
"seekableunbundlepart" class. Previous instantiators of "unbundlepart"
now instantiate "seekableunbundlepart." This preserves backwards
compatibility. The coupling between the classes is still tight:
"unbundlepart" cannot be used on its own. This will be addressed
in subsequent commits.
Differential Revision: https://phab.mercurial-scm.org/D1386
Criss cross merging
$ hg init criss-cross
$ cd criss-cross
$ echo '0 base' > f1
$ echo '0 base' > f2
$ hg ci -Aqm '0 base'
$ echo '1 first change' > f1
$ hg ci -m '1 first change f1'
$ hg up -qr0
$ echo '2 first change' > f2
$ mkdir d1
$ echo '0 base' > d1/f3
$ echo '0 base' > d1/f4
$ hg add -q d1
$ hg ci -qm '2 first change f2'
$ hg merge -qr 1
$ hg rm d1/f3
$ hg mv -q d1 d2
$ hg ci -m '3 merge'
$ hg up -qr2
$ hg merge -qr1
$ hg ci -qm '4 merge'
$ echo '5 second change' > f1
$ hg ci -m '5 second change f1'
$ hg up -r3
2 files updated, 0 files merged, 2 files removed, 0 files unresolved
$ echo '6 second change' > f2
$ hg ci -m '6 second change f2'
$ hg log -G
@ changeset: 6:6373bbfdae1d
| tag: tip
| parent: 3:c202c8af058d
| user: test
| date: Thu Jan 01 00:00:00 1970 +0000
| summary: 6 second change f2
|
| o changeset: 5:e673248094b1
| | user: test
| | date: Thu Jan 01 00:00:00 1970 +0000
| | summary: 5 second change f1
| |
| o changeset: 4:177f58377c06
| |\ parent: 2:d1d156401c1b
| | | parent: 1:0f6b37dbe527
| | | user: test
| | | date: Thu Jan 01 00:00:00 1970 +0000
| | | summary: 4 merge
| | |
o---+ changeset: 3:c202c8af058d
| | | parent: 2:d1d156401c1b
|/ / parent: 1:0f6b37dbe527
| | user: test
| | date: Thu Jan 01 00:00:00 1970 +0000
| | summary: 3 merge
| |
| o changeset: 2:d1d156401c1b
| | parent: 0:40494bf2444c
| | user: test
| | date: Thu Jan 01 00:00:00 1970 +0000
| | summary: 2 first change f2
| |
o | changeset: 1:0f6b37dbe527
|/ user: test
| date: Thu Jan 01 00:00:00 1970 +0000
| summary: 1 first change f1
|
o changeset: 0:40494bf2444c
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: 0 base
$ hg merge -v --debug --tool internal:dump 5 --config merge.preferancestor='!'
note: using 0f6b37dbe527 as ancestor of 6373bbfdae1d and e673248094b1
alternatively, use --config merge.preferancestor=d1d156401c1b
searching for copies back to rev 3
unmatched files in local:
d2/f4
unmatched files in other:
d1/f3
d1/f4
all copies found (* = to merge, ! = divergent, % = renamed and deleted):
src: 'd1/f4' -> dst: 'd2/f4'
checking for directory renames
discovered dir src: 'd1/' -> dst: 'd2/'
pending file src: 'd1/f3' -> dst: 'd2/f3'
pending file src: 'd1/f4' -> dst: 'd2/f4'
resolving manifests
branchmerge: True, force: False, partial: False
ancestor: 0f6b37dbe527, local: 6373bbfdae1d+, remote: e673248094b1
preserving d2/f4 for resolve of d2/f4
preserving f2 for resolve of f2
f1: remote is newer -> g
getting f1
d2/f3: local directory rename - get from d1/f3 -> dg
getting d1/f3 to d2/f3
d2/f4: local directory rename, both created -> m (premerge)
f2: versions differ -> m (premerge)
picked tool ':dump' for f2 (binary False symlink False changedelete False)
merging f2
my f2@6373bbfdae1d+ other f2@e673248094b1 ancestor f2@0f6b37dbe527
f2: versions differ -> m (merge)
picked tool ':dump' for f2 (binary False symlink False changedelete False)
my f2@6373bbfdae1d+ other f2@e673248094b1 ancestor f2@0f6b37dbe527
3 files updated, 0 files merged, 0 files removed, 1 files unresolved
use 'hg resolve' to retry unresolved file merges or 'hg update -C .' to abandon
[1]
$ f --dump --recurse *
d2: directory with 2 files
d2/f3: (glob)
>>>
0 base
<<<
d2/f4: (glob)
>>>
0 base
<<<
f1:
>>>
5 second change
<<<
f2:
>>>
6 second change
<<<
f2.base:
>>>
0 base
<<<
f2.local:
>>>
6 second change
<<<
f2.orig:
>>>
6 second change
<<<
f2.other:
>>>
2 first change
<<<
$ hg up -qC .
$ hg merge -v --tool internal:dump 5 --config merge.preferancestor="null 40663881 3b08d"
note: using 0f6b37dbe527 as ancestor of 6373bbfdae1d and e673248094b1
alternatively, use --config merge.preferancestor=d1d156401c1b
resolving manifests
getting f1
getting d1/f3 to d2/f3
merging f2
3 files updated, 0 files merged, 0 files removed, 1 files unresolved
use 'hg resolve' to retry unresolved file merges or 'hg update -C .' to abandon
[1]
Redo merge with merge.preferancestor="*" to enable bid merge
$ rm f*
$ hg up -qC .
$ hg merge -v --debug --tool internal:dump 5 --config merge.preferancestor="*"
note: merging 6373bbfdae1d+ and e673248094b1 using bids from ancestors 0f6b37dbe527 and d1d156401c1b
calculating bids for ancestor 0f6b37dbe527
searching for copies back to rev 3
unmatched files in local:
d2/f4
unmatched files in other:
d1/f3
d1/f4
all copies found (* = to merge, ! = divergent, % = renamed and deleted):
src: 'd1/f4' -> dst: 'd2/f4'
checking for directory renames
discovered dir src: 'd1/' -> dst: 'd2/'
pending file src: 'd1/f3' -> dst: 'd2/f3'
pending file src: 'd1/f4' -> dst: 'd2/f4'
resolving manifests
branchmerge: True, force: False, partial: False
ancestor: 0f6b37dbe527, local: 6373bbfdae1d+, remote: e673248094b1
d2/f3: local directory rename - get from d1/f3 -> dg
d2/f4: local directory rename, both created -> m
f1: remote is newer -> g
f2: versions differ -> m
calculating bids for ancestor d1d156401c1b
searching for copies back to rev 3
unmatched files in local:
d2/f4
all copies found (* = to merge, ! = divergent, % = renamed and deleted):
src: 'd1/f4' -> dst: 'd2/f4'
checking for directory renames
discovered dir src: 'd1/' -> dst: 'd2/'
resolving manifests
branchmerge: True, force: False, partial: False
ancestor: d1d156401c1b, local: 6373bbfdae1d+, remote: e673248094b1
f1: versions differ -> m
f2: remote unchanged -> k
auction for merging merge bids
d2/f3: consensus for dg
d2/f4: consensus for m
f1: picking 'get' action
f2: picking 'keep' action
end of auction
preserving d2/f4 for resolve of d2/f4
f1: remote is newer -> g
getting f1
f2: remote unchanged -> k
d2/f3: local directory rename - get from d1/f3 -> dg
getting d1/f3 to d2/f3
d2/f4: local directory rename, both created -> m (premerge)
3 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ f --dump --recurse *
d2: directory with 2 files
d2/f3: (glob)
>>>
0 base
<<<
d2/f4: (glob)
>>>
0 base
<<<
f1:
>>>
5 second change
<<<
f2:
>>>
6 second change
<<<
The other way around:
$ hg up -C -r5
4 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ hg merge -v --debug --config merge.preferancestor="*"
note: merging e673248094b1+ and 6373bbfdae1d using bids from ancestors 0f6b37dbe527 and d1d156401c1b
calculating bids for ancestor 0f6b37dbe527
searching for copies back to rev 3
unmatched files in local:
d1/f3
d1/f4
unmatched files in other:
d2/f4
all copies found (* = to merge, ! = divergent, % = renamed and deleted):
src: 'd1/f4' -> dst: 'd2/f4'
checking for directory renames
discovered dir src: 'd1/' -> dst: 'd2/'
pending file src: 'd1/f3' -> dst: 'd2/f3'
pending file src: 'd1/f4' -> dst: 'd2/f4'
resolving manifests
branchmerge: True, force: False, partial: False
ancestor: 0f6b37dbe527, local: e673248094b1+, remote: 6373bbfdae1d
d2/f3: remote directory rename - move from d1/f3 -> dm
d2/f4: remote directory rename, both created -> m
f1: remote unchanged -> k
f2: versions differ -> m
calculating bids for ancestor d1d156401c1b
searching for copies back to rev 3
unmatched files in other:
d2/f4
all copies found (* = to merge, ! = divergent, % = renamed and deleted):
src: 'd1/f4' -> dst: 'd2/f4'
checking for directory renames
discovered dir src: 'd1/' -> dst: 'd2/'
resolving manifests
branchmerge: True, force: False, partial: False
ancestor: d1d156401c1b, local: e673248094b1+, remote: 6373bbfdae1d
d1/f3: other deleted -> r
d1/f4: other deleted -> r
d2/f4: remote created -> g
f1: versions differ -> m
f2: remote is newer -> g
auction for merging merge bids
d1/f3: consensus for r
d1/f4: consensus for r
d2/f3: consensus for dm
d2/f4: picking 'get' action
f1: picking 'keep' action
f2: picking 'get' action
end of auction
d1/f3: other deleted -> r
removing d1/f3
d1/f4: other deleted -> r
removing d1/f4
d2/f4: remote created -> g
getting d2/f4
f2: remote is newer -> g
getting f2
f1: remote unchanged -> k
2 files updated, 0 files merged, 2 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ f --dump --recurse *
d2: directory with 2 files
d2/f3: (glob)
>>>
0 base
<<<
d2/f4: (glob)
>>>
0 base
<<<
f1:
>>>
5 second change
<<<
f2:
>>>
6 second change
<<<
Verify how the output looks and and how verbose it is:
$ hg up -qC
$ hg merge
2 files updated, 0 files merged, 2 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ hg up -qC tip
$ hg merge -v
note: merging 6373bbfdae1d+ and e673248094b1 using bids from ancestors 0f6b37dbe527 and d1d156401c1b
calculating bids for ancestor 0f6b37dbe527
resolving manifests
calculating bids for ancestor d1d156401c1b
resolving manifests
auction for merging merge bids
d2/f3: consensus for dg
d2/f4: consensus for m
f1: picking 'get' action
f2: picking 'keep' action
end of auction
getting f1
getting d1/f3 to d2/f3
3 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ hg up -qC
$ hg merge -v --debug --config merge.preferancestor="*"
note: merging 6373bbfdae1d+ and e673248094b1 using bids from ancestors 0f6b37dbe527 and d1d156401c1b
calculating bids for ancestor 0f6b37dbe527
searching for copies back to rev 3
unmatched files in local:
d2/f4
unmatched files in other:
d1/f3
d1/f4
all copies found (* = to merge, ! = divergent, % = renamed and deleted):
src: 'd1/f4' -> dst: 'd2/f4'
checking for directory renames
discovered dir src: 'd1/' -> dst: 'd2/'
pending file src: 'd1/f3' -> dst: 'd2/f3'
pending file src: 'd1/f4' -> dst: 'd2/f4'
resolving manifests
branchmerge: True, force: False, partial: False
ancestor: 0f6b37dbe527, local: 6373bbfdae1d+, remote: e673248094b1
d2/f3: local directory rename - get from d1/f3 -> dg
d2/f4: local directory rename, both created -> m
f1: remote is newer -> g
f2: versions differ -> m
calculating bids for ancestor d1d156401c1b
searching for copies back to rev 3
unmatched files in local:
d2/f4
all copies found (* = to merge, ! = divergent, % = renamed and deleted):
src: 'd1/f4' -> dst: 'd2/f4'
checking for directory renames
discovered dir src: 'd1/' -> dst: 'd2/'
resolving manifests
branchmerge: True, force: False, partial: False
ancestor: d1d156401c1b, local: 6373bbfdae1d+, remote: e673248094b1
f1: versions differ -> m
f2: remote unchanged -> k
auction for merging merge bids
d2/f3: consensus for dg
d2/f4: consensus for m
f1: picking 'get' action
f2: picking 'keep' action
end of auction
preserving d2/f4 for resolve of d2/f4
f1: remote is newer -> g
getting f1
f2: remote unchanged -> k
d2/f3: local directory rename - get from d1/f3 -> dg
getting d1/f3 to d2/f3
d2/f4: local directory rename, both created -> m (premerge)
3 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ cd ..
http://stackoverflow.com/questions/9350005/how-do-i-specify-a-merge-base-to-use-in-a-hg-merge/9430810
$ hg init ancestor-merging
$ cd ancestor-merging
$ echo a > x
$ hg commit -A -m a x
$ hg update -q 0
$ echo b >> x
$ hg commit -m b
$ hg update -q 0
$ echo c >> x
$ hg commit -qm c
$ hg update -q 1
$ hg merge -q --tool internal:local 2
$ echo c >> x
$ hg commit -m bc
$ hg update -q 2
$ hg merge -q --tool internal:local 1
$ echo b >> x
$ hg commit -qm cb
$ hg merge --config merge.preferancestor='!'
note: using 70008a2163f6 as ancestor of 0d355fdef312 and 4b8b546a3eef
alternatively, use --config merge.preferancestor=b211bbc6eb3c
merging x
0 files updated, 1 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ cat x
a
c
b
c
$ hg up -qC .
$ hg merge --config merge.preferancestor=b211bbc6eb3c
note: using b211bbc6eb3c as ancestor of 0d355fdef312 and 4b8b546a3eef
alternatively, use --config merge.preferancestor=70008a2163f6
merging x
0 files updated, 1 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ cat x
a
b
c
b
$ hg up -qC .
$ hg merge -v --config merge.preferancestor="*"
note: merging 0d355fdef312+ and 4b8b546a3eef using bids from ancestors 70008a2163f6 and b211bbc6eb3c
calculating bids for ancestor 70008a2163f6
resolving manifests
calculating bids for ancestor b211bbc6eb3c
resolving manifests
auction for merging merge bids
x: multiple bids for merge action:
versions differ -> m
versions differ -> m
x: ambiguous merge - picked m action
end of auction
merging x
0 files updated, 1 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ cat x
a
c
b
c
Verify that the old context ancestor works with / despite preferancestor:
$ hg log -r 'ancestor(head())' --config merge.preferancestor=1 -T '{rev}\n'
1
$ hg log -r 'ancestor(head())' --config merge.preferancestor=2 -T '{rev}\n'
2
$ hg log -r 'ancestor(head())' --config merge.preferancestor=3 -T '{rev}\n'
1
$ hg log -r 'ancestor(head())' --config merge.preferancestor='1337 * - 2' -T '{rev}\n'
2
$ cd ..