wireproto: add streams to frame-based protocol
Previously, the frame-based protocol was just a series of frames,
with each frame associated with a request ID.
In order to scale the protocol, we'll want to enable the use of
compression. While it is possible to enable compression at the
socket/pipe level, this has its disadvantages. The big one is it
undermines the point of frames being standalone, atomic units that
can be read and written: if you add compression above the framing
protocol, you are back to having a stream-based protocol as opposed
to something frame-based.
So in order to preserve frames, compression needs to occur at
the frame payload level.
Compressing each frame's payload individually will limit compression
ratios because the window size of the compressor will be limited
by the max frame size, which is 32-64kb as currently defined. It
will also add CPU overhead, as it is more efficient for compressors
to operate on fewer, larger blocks of data than more, smaller blocks.
So compressing each frame independently is out.
This means we need to compress each frame's payload as if it is part
of a larger stream.
The simplest approach is to have 1 stream per connection. This
could certainly work. However, it has disadvantages (documented below).
We could also have 1 stream per RPC/command invocation. (This is the
model HTTP/2 goes with.) This also has disadvantages.
The main disadvantage to one global stream is that it has the very
real potential to create CPU bottlenecks doing compression. Networks
are only getting faster and the performance of single CPU cores has
been relatively flat. Newer compression formats like zstandard offer
better CPU cycle efficiency than predecessors like zlib. But it still
all too common to saturate your CPU with compression overhead long
before you saturate the network pipe.
The main disadvantage with streams per request is that you can't
reap the benefits of the compression context for multiple requests.
For example, if you send 1000 RPC requests (or HTTP/2 requests for
that matter), the response to each would have its own compression
context. The overall size of the raw responses would be larger because
compression contexts wouldn't be able to reference data from another
request or response.
The approach for streams as implemented in this commit is to support
N streams per connection and for streams to potentially span requests
and responses. As explained by the added internals docs, this
facilitates servers and clients delegating independent streams and
compression to independent threads / CPU cores. This helps alleviate
the CPU bottleneck of compression. This design also allows compression
contexts to be reused across requests/responses. This can result in
improved compression ratios and less overhead for compressors and
decompressors having to build new contexts.
Another feature that was defined was the ability for individual frames
within a stream to declare whether that individual frame's payload
uses the content encoding (read: compression) defined by the stream.
The idea here is that some servers may serve data from a combination
of caches and dynamic resolution. Data coming from caches may be
pre-compressed. We want to facilitate servers being able to essentially
stream bytes from caches to the wire with minimal overhead. Being
able to mix and match with frames are compressed within a stream
enables these types of advanced server functionality.
This commit defines the new streams mechanism. Basic code for
supporting streams in frames has been added. But that code is
seriously lacking and doesn't fully conform to the defined protocol.
For example, we don't close any streams. And support for content
encoding within streams is not yet implemented. The change was
rather invasive and I didn't think it would be reasonable to implement
the entire feature in a single commit.
For the record, I would have loved to reuse an existing multiplexing
protocol to build the new wire protocol on top of. However, I couldn't
find a protocol that offers the performance and scaling characteristics
that I desired. Namely, it should support multiple compression
contexts to facilitate scaling out to multiple CPU cores and
compression contexts should be able to live longer than single RPC
requests. HTTP/2 *almost* fits the bill. But the semantics of HTTP
message exchange state that streams can only live for a single
request-response. We /could/ tunnel on top of HTTP/2 streams and
frames with HEADER and DATA frames. But there's no guarantee that
HTTP/2 libraries and proxies would allow us to use HTTP/2 streams
and frames without the HTTP message exchange semantics defined in
RFC 7540 Section 8. Other RPC protocols like gRPC tunnel are built
on top of HTTP/2 and thus preserve its semantics of stream per
RPC invocation. Even QUIC does this. We could attempt to invent a
higher-level stream that spans HTTP/2 streams. But this would be
violating HTTP/2 because there is no guarantee that HTTP/2 streams
are routed to the same server. The best we can do - which is what
this protocol does - is shoehorn all request and response data into
a single HTTP message and create streams within. At that point, we've
defined a Content-Type in HTTP parlance. It just so happens our
media type can also work as a standalone, stream-based protocol,
without leaning on HTTP or similar protocol.
Differential Revision: https://phab.mercurial-scm.org/D2907
Test for the heuristic copytracing algorithm
============================================
$ cat >> $TESTTMP/copytrace.sh << '__EOF__'
> initclient() {
> cat >> $1/.hg/hgrc <<EOF
> [experimental]
> copytrace = heuristics
> copytrace.sourcecommitlimit = -1
> EOF
> }
> __EOF__
$ . "$TESTTMP/copytrace.sh"
$ cat >> $HGRCPATH << EOF
> [extensions]
> rebase=
> shelve=
> EOF
NOTE: calling initclient() set copytrace.sourcecommitlimit=-1 as we want to
prevent the full copytrace algorithm to run and test the heuristic algorithm
without complexing the test cases with public and draft commits.
Check filename heuristics (same dirname and same basename)
----------------------------------------------------------
$ hg init repo
$ initclient repo
$ cd repo
$ echo a > a
$ mkdir dir
$ echo a > dir/file.txt
$ hg addremove
adding a
adding dir/file.txt
$ hg ci -m initial
$ hg mv a b
$ hg mv -q dir dir2
$ hg ci -m 'mv a b, mv dir/ dir2/'
$ hg up -q 0
$ echo b > a
$ echo b > dir/file.txt
$ hg ci -qm 'mod a, mod dir/file.txt'
$ hg log -G -T 'changeset: {node}\n desc: {desc}\n'
@ changeset: 557f403c0afd2a3cf15d7e2fb1f1001a8b85e081
| desc: mod a, mod dir/file.txt
| o changeset: 928d74bc9110681920854d845c06959f6dfc9547
|/ desc: mv a b, mv dir/ dir2/
o changeset: 3c482b16e54596fed340d05ffaf155f156cda7ee
desc: initial
$ hg rebase -s . -d 1
rebasing 2:557f403c0afd "mod a, mod dir/file.txt" (tip)
merging b and a to b
merging dir2/file.txt and dir/file.txt to dir2/file.txt
saved backup bundle to $TESTTMP/repo/.hg/strip-backup/557f403c0afd-9926eeff-rebase.hg
$ cd ..
$ rm -rf repo
Make sure filename heuristics do not when they are not related
--------------------------------------------------------------
$ hg init repo
$ initclient repo
$ cd repo
$ echo 'somecontent' > a
$ hg add a
$ hg ci -m initial
$ hg rm a
$ echo 'completelydifferentcontext' > b
$ hg add b
$ hg ci -m 'rm a, add b'
$ hg up -q 0
$ printf 'somecontent\nmoarcontent' > a
$ hg ci -qm 'mode a'
$ hg log -G -T 'changeset: {node}\n desc: {desc}\n'
@ changeset: d526312210b9e8f795d576a77dc643796384d86e
| desc: mode a
| o changeset: 46985f76c7e5e5123433527f5c8526806145650b
|/ desc: rm a, add b
o changeset: e5b71fb099c29d9172ef4a23485aaffd497e4cc0
desc: initial
$ hg rebase -s . -d 1
rebasing 2:d526312210b9 "mode a" (tip)
other [source] changed a which local [dest] deleted
use (c)hanged version, leave (d)eleted, or leave (u)nresolved? u
unresolved conflicts (see hg resolve, then hg rebase --continue)
[1]
$ cd ..
$ rm -rf repo
Test when lca didn't modified the file that was moved
-----------------------------------------------------
$ hg init repo
$ initclient repo
$ cd repo
$ echo 'somecontent' > a
$ hg add a
$ hg ci -m initial
$ echo c > c
$ hg add c
$ hg ci -m randomcommit
$ hg mv a b
$ hg ci -m 'mv a b'
$ hg up -q 1
$ echo b > a
$ hg ci -qm 'mod a'
$ hg log -G -T 'changeset: {node}\n desc: {desc}, phase: {phase}\n'
@ changeset: 9d5cf99c3d9f8e8b05ba55421f7f56530cfcf3bc
| desc: mod a, phase: draft
| o changeset: d760186dd240fc47b91eb9f0b58b0002aaeef95d
|/ desc: mv a b, phase: draft
o changeset: 48e1b6ba639d5d7fb313fa7989eebabf99c9eb83
| desc: randomcommit, phase: draft
o changeset: e5b71fb099c29d9172ef4a23485aaffd497e4cc0
desc: initial, phase: draft
$ hg rebase -s . -d 2
rebasing 3:9d5cf99c3d9f "mod a" (tip)
merging b and a to b
saved backup bundle to $TESTTMP/repo/.hg/strip-backup/9d5cf99c3d9f-f02358cc-rebase.hg
$ cd ..
$ rm -rf repo
Rebase "backwards"
------------------
$ hg init repo
$ initclient repo
$ cd repo
$ echo 'somecontent' > a
$ hg add a
$ hg ci -m initial
$ echo c > c
$ hg add c
$ hg ci -m randomcommit
$ hg mv a b
$ hg ci -m 'mv a b'
$ hg up -q 2
$ echo b > b
$ hg ci -qm 'mod b'
$ hg log -G -T 'changeset: {node}\n desc: {desc}\n'
@ changeset: fbe97126b3969056795c462a67d93faf13e4d298
| desc: mod b
o changeset: d760186dd240fc47b91eb9f0b58b0002aaeef95d
| desc: mv a b
o changeset: 48e1b6ba639d5d7fb313fa7989eebabf99c9eb83
| desc: randomcommit
o changeset: e5b71fb099c29d9172ef4a23485aaffd497e4cc0
desc: initial
$ hg rebase -s . -d 0
rebasing 3:fbe97126b396 "mod b" (tip)
merging a and b to a
saved backup bundle to $TESTTMP/repo/.hg/strip-backup/fbe97126b396-cf5452a1-rebase.hg
$ cd ..
$ rm -rf repo
Check a few potential move candidates
-------------------------------------
$ hg init repo
$ initclient repo
$ cd repo
$ mkdir dir
$ echo a > dir/a
$ hg add dir/a
$ hg ci -qm initial
$ hg mv dir/a dir/b
$ hg ci -qm 'mv dir/a dir/b'
$ mkdir dir2
$ echo b > dir2/a
$ hg add dir2/a
$ hg ci -qm 'create dir2/a'
$ hg up -q 0
$ echo b > dir/a
$ hg ci -qm 'mod dir/a'
$ hg log -G -T 'changeset: {node}\n desc: {desc}\n'
@ changeset: 6b2f4cece40fd320f41229f23821256ffc08efea
| desc: mod dir/a
| o changeset: 4494bf7efd2e0dfdd388e767fb913a8a3731e3fa
| | desc: create dir2/a
| o changeset: b1784dfab6ea6bfafeb11c0ac50a2981b0fe6ade
|/ desc: mv dir/a dir/b
o changeset: 36859b8907c513a3a87ae34ba5b1e7eea8c20944
desc: initial
$ hg rebase -s . -d 2
rebasing 3:6b2f4cece40f "mod dir/a" (tip)
merging dir/b and dir/a to dir/b
saved backup bundle to $TESTTMP/repo/.hg/strip-backup/6b2f4cece40f-503efe60-rebase.hg
$ cd ..
$ rm -rf repo
Test the copytrace.movecandidateslimit with many move candidates
----------------------------------------------------------------
$ hg init repo
$ initclient repo
$ cd repo
$ echo a > a
$ hg add a
$ hg ci -m initial
$ hg mv a foo
$ echo a > b
$ echo a > c
$ echo a > d
$ echo a > e
$ echo a > f
$ echo a > g
$ hg add b
$ hg add c
$ hg add d
$ hg add e
$ hg add f
$ hg add g
$ hg ci -m 'mv a foo, add many files'
$ hg up -q ".^"
$ echo b > a
$ hg ci -m 'mod a'
created new head
$ hg log -G -T 'changeset: {node}\n desc: {desc}\n'
@ changeset: ef716627c70bf4ca0bdb623cfb0d6fe5b9acc51e
| desc: mod a
| o changeset: 8329d5c6bf479ec5ca59b9864f3f45d07213f5a4
|/ desc: mv a foo, add many files
o changeset: 1451231c87572a7d3f92fc210b4b35711c949a98
desc: initial
With small limit
$ hg rebase -s 2 -d 1 --config experimental.copytrace.movecandidateslimit=0
rebasing 2:ef716627c70b "mod a" (tip)
skipping copytracing for 'a', more candidates than the limit: 7
other [source] changed a which local [dest] deleted
use (c)hanged version, leave (d)eleted, or leave (u)nresolved? u
unresolved conflicts (see hg resolve, then hg rebase --continue)
[1]
$ hg rebase --abort
rebase aborted
With default limit which is 100
$ hg rebase -s 2 -d 1
rebasing 2:ef716627c70b "mod a" (tip)
merging foo and a to foo
saved backup bundle to $TESTTMP/repo/.hg/strip-backup/ef716627c70b-24681561-rebase.hg
$ cd ..
$ rm -rf repo
Move file in one branch and delete it in another
-----------------------------------------------
$ hg init repo
$ initclient repo
$ cd repo
$ echo a > a
$ hg add a
$ hg ci -m initial
$ hg mv a b
$ hg ci -m 'mv a b'
$ hg up -q ".^"
$ hg rm a
$ hg ci -m 'del a'
created new head
$ hg log -G -T 'changeset: {node}\n desc: {desc}, phase: {phase}\n'
@ changeset: 7d61ee3b1e48577891a072024968428ba465c47b
| desc: del a, phase: draft
| o changeset: 472e38d57782172f6c6abed82a94ca0d998c3a22
|/ desc: mv a b, phase: draft
o changeset: 1451231c87572a7d3f92fc210b4b35711c949a98
desc: initial, phase: draft
$ hg rebase -s 1 -d 2
rebasing 1:472e38d57782 "mv a b"
saved backup bundle to $TESTTMP/repo/.hg/strip-backup/472e38d57782-17d50e29-rebase.hg
$ hg up -q c492ed3c7e35dcd1dc938053b8adf56e2cfbd062
$ ls
b
$ cd ..
$ rm -rf repo
Move a directory in draft branch
--------------------------------
$ hg init repo
$ initclient repo
$ cd repo
$ mkdir dir
$ echo a > dir/a
$ hg add dir/a
$ hg ci -qm initial
$ echo b > dir/a
$ hg ci -qm 'mod dir/a'
$ hg up -q ".^"
$ hg mv -q dir/ dir2
$ hg ci -qm 'mv dir/ dir2/'
$ hg log -G -T 'changeset: {node}\n desc: {desc}\n'
@ changeset: a33d80b6e352591dfd82784e1ad6cdd86b25a239
| desc: mv dir/ dir2/
| o changeset: 6b2f4cece40fd320f41229f23821256ffc08efea
|/ desc: mod dir/a
o changeset: 36859b8907c513a3a87ae34ba5b1e7eea8c20944
desc: initial
$ hg rebase -s . -d 1
rebasing 2:a33d80b6e352 "mv dir/ dir2/" (tip)
merging dir/a and dir2/a to dir2/a
saved backup bundle to $TESTTMP/repo/.hg/strip-backup/a33d80b6e352-fecb9ada-rebase.hg
$ cd ..
$ rm -rf server
$ rm -rf repo
Move file twice and rebase mod on top of moves
----------------------------------------------
$ hg init repo
$ initclient repo
$ cd repo
$ echo a > a
$ hg add a
$ hg ci -m initial
$ hg mv a b
$ hg ci -m 'mv a b'
$ hg mv b c
$ hg ci -m 'mv b c'
$ hg up -q 0
$ echo c > a
$ hg ci -m 'mod a'
created new head
$ hg log -G -T 'changeset: {node}\n desc: {desc}\n'
@ changeset: d413169422167a3fa5275fc5d71f7dea9f5775f3
| desc: mod a
| o changeset: d3efd280421d24f9f229997c19e654761c942a71
| | desc: mv b c
| o changeset: 472e38d57782172f6c6abed82a94ca0d998c3a22
|/ desc: mv a b
o changeset: 1451231c87572a7d3f92fc210b4b35711c949a98
desc: initial
$ hg rebase -s . -d 2
rebasing 3:d41316942216 "mod a" (tip)
merging c and a to c
saved backup bundle to $TESTTMP/repo/.hg/strip-backup/d41316942216-2b5949bc-rebase.hg
$ cd ..
$ rm -rf repo
Move file twice and rebase moves on top of mods
-----------------------------------------------
$ hg init repo
$ initclient repo
$ cd repo
$ echo a > a
$ hg add a
$ hg ci -m initial
$ hg mv a b
$ hg ci -m 'mv a b'
$ hg mv b c
$ hg ci -m 'mv b c'
$ hg up -q 0
$ echo c > a
$ hg ci -m 'mod a'
created new head
$ hg log -G -T 'changeset: {node}\n desc: {desc}\n'
@ changeset: d413169422167a3fa5275fc5d71f7dea9f5775f3
| desc: mod a
| o changeset: d3efd280421d24f9f229997c19e654761c942a71
| | desc: mv b c
| o changeset: 472e38d57782172f6c6abed82a94ca0d998c3a22
|/ desc: mv a b
o changeset: 1451231c87572a7d3f92fc210b4b35711c949a98
desc: initial
$ hg rebase -s 1 -d .
rebasing 1:472e38d57782 "mv a b"
merging a and b to b
rebasing 2:d3efd280421d "mv b c"
merging b and c to c
saved backup bundle to $TESTTMP/repo/.hg/strip-backup/472e38d57782-ab8d3c58-rebase.hg
$ cd ..
$ rm -rf repo
Move one file and add another file in the same folder in one branch, modify file in another branch
--------------------------------------------------------------------------------------------------
$ hg init repo
$ initclient repo
$ cd repo
$ echo a > a
$ hg add a
$ hg ci -m initial
$ hg mv a b
$ hg ci -m 'mv a b'
$ echo c > c
$ hg add c
$ hg ci -m 'add c'
$ hg up -q 0
$ echo b > a
$ hg ci -m 'mod a'
created new head
$ hg log -G -T 'changeset: {node}\n desc: {desc}\n'
@ changeset: ef716627c70bf4ca0bdb623cfb0d6fe5b9acc51e
| desc: mod a
| o changeset: b1a6187e79fbce851bb584eadcb0cc4a80290fd9
| | desc: add c
| o changeset: 472e38d57782172f6c6abed82a94ca0d998c3a22
|/ desc: mv a b
o changeset: 1451231c87572a7d3f92fc210b4b35711c949a98
desc: initial
$ hg rebase -s . -d 2
rebasing 3:ef716627c70b "mod a" (tip)
merging b and a to b
saved backup bundle to $TESTTMP/repo/.hg/strip-backup/ef716627c70b-24681561-rebase.hg
$ ls
b
c
$ cat b
b
$ rm -rf repo
Merge test
----------
$ hg init repo
$ initclient repo
$ cd repo
$ echo a > a
$ hg add a
$ hg ci -m initial
$ echo b > a
$ hg ci -m 'modify a'
$ hg up -q 0
$ hg mv a b
$ hg ci -m 'mv a b'
created new head
$ hg up -q 2
$ hg log -G -T 'changeset: {node}\n desc: {desc}\n'
@ changeset: 472e38d57782172f6c6abed82a94ca0d998c3a22
| desc: mv a b
| o changeset: b0357b07f79129a3d08a68621271ca1352ae8a09
|/ desc: modify a
o changeset: 1451231c87572a7d3f92fc210b4b35711c949a98
desc: initial
$ hg merge 1
merging b and a to b
0 files updated, 1 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ hg ci -m merge
$ ls
b
$ cd ..
$ rm -rf repo
Copy and move file
------------------
$ hg init repo
$ initclient repo
$ cd repo
$ echo a > a
$ hg add a
$ hg ci -m initial
$ hg cp a c
$ hg mv a b
$ hg ci -m 'cp a c, mv a b'
$ hg up -q 0
$ echo b > a
$ hg ci -m 'mod a'
created new head
$ hg log -G -T 'changeset: {node}\n desc: {desc}\n'
@ changeset: ef716627c70bf4ca0bdb623cfb0d6fe5b9acc51e
| desc: mod a
| o changeset: 4fc3fd13fbdb89ada6b75bfcef3911a689a0dde8
|/ desc: cp a c, mv a b
o changeset: 1451231c87572a7d3f92fc210b4b35711c949a98
desc: initial
$ hg rebase -s . -d 1
rebasing 2:ef716627c70b "mod a" (tip)
merging b and a to b
merging c and a to c
saved backup bundle to $TESTTMP/repo/repo/.hg/strip-backup/ef716627c70b-24681561-rebase.hg
$ ls
b
c
$ cat b
b
$ cat c
b
$ cd ..
$ rm -rf repo
Do a merge commit with many consequent moves in one branch
----------------------------------------------------------
$ hg init repo
$ initclient repo
$ cd repo
$ echo a > a
$ hg add a
$ hg ci -m initial
$ echo b > a
$ hg ci -qm 'mod a'
$ hg up -q ".^"
$ hg mv a b
$ hg ci -qm 'mv a b'
$ hg mv b c
$ hg ci -qm 'mv b c'
$ hg up -q 1
$ hg log -G -T 'changeset: {node}\n desc: {desc}\n'
o changeset: d3efd280421d24f9f229997c19e654761c942a71
| desc: mv b c
o changeset: 472e38d57782172f6c6abed82a94ca0d998c3a22
| desc: mv a b
| @ changeset: ef716627c70bf4ca0bdb623cfb0d6fe5b9acc51e
|/ desc: mod a
o changeset: 1451231c87572a7d3f92fc210b4b35711c949a98
desc: initial
$ hg merge 3
merging a and c to c
0 files updated, 1 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ hg ci -qm 'merge'
$ hg log -G -T 'changeset: {node}\n desc: {desc}, phase: {phase}\n'
@ changeset: cd29b0d08c0f39bfed4cde1b40e30f419db0c825
|\ desc: merge, phase: draft
| o changeset: d3efd280421d24f9f229997c19e654761c942a71
| | desc: mv b c, phase: draft
| o changeset: 472e38d57782172f6c6abed82a94ca0d998c3a22
| | desc: mv a b, phase: draft
o | changeset: ef716627c70bf4ca0bdb623cfb0d6fe5b9acc51e
|/ desc: mod a, phase: draft
o changeset: 1451231c87572a7d3f92fc210b4b35711c949a98
desc: initial, phase: draft
$ ls
c
$ cd ..
$ rm -rf repo
Test shelve/unshelve
-------------------
$ hg init repo
$ initclient repo
$ cd repo
$ echo a > a
$ hg add a
$ hg ci -m initial
$ echo b > a
$ hg shelve
shelved as default
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg mv a b
$ hg ci -m 'mv a b'
$ hg log -G -T 'changeset: {node}\n desc: {desc}\n'
@ changeset: 472e38d57782172f6c6abed82a94ca0d998c3a22
| desc: mv a b
o changeset: 1451231c87572a7d3f92fc210b4b35711c949a98
desc: initial
$ hg unshelve
unshelving change 'default'
rebasing shelved changes
rebasing 2:45f63161acea "changes to: initial" (tip)
merging b and a to b
$ ls
b
$ cat b
b
$ cd ..
$ rm -rf repo
Test full copytrace ability on draft branch
-------------------------------------------
File directory and base name changed in same move
$ hg init repo
$ initclient repo
$ mkdir repo/dir1
$ cd repo/dir1
$ echo a > a
$ hg add a
$ hg ci -qm initial
$ cd ..
$ hg mv -q dir1 dir2
$ hg mv dir2/a dir2/b
$ hg ci -qm 'mv a b; mv dir1 dir2'
$ hg up -q '.^'
$ cd dir1
$ echo b >> a
$ cd ..
$ hg ci -qm 'mod a'
$ hg log -G -T 'changeset {node}\n desc {desc}, phase: {phase}\n'
@ changeset 6207d2d318e710b882e3d5ada2a89770efc42c96
| desc mod a, phase: draft
| o changeset abffdd4e3dfc04bc375034b970299b2a309a1cce
|/ desc mv a b; mv dir1 dir2, phase: draft
o changeset 81973cd24b58db2fdf18ce3d64fb2cc3284e9ab3
desc initial, phase: draft
$ hg rebase -s . -d 1 --config experimental.copytrace.sourcecommitlimit=100
rebasing 2:6207d2d318e7 "mod a" (tip)
merging dir2/b and dir1/a to dir2/b
saved backup bundle to $TESTTMP/repo/repo/.hg/strip-backup/6207d2d318e7-1c9779ad-rebase.hg
$ cat dir2/b
a
b
$ cd ..
$ rm -rf repo
Move directory in one merge parent, while adding file to original directory
in other merge parent. File moved on rebase.
$ hg init repo
$ initclient repo
$ mkdir repo/dir1
$ cd repo/dir1
$ echo dummy > dummy
$ hg add dummy
$ cd ..
$ hg ci -qm initial
$ cd dir1
$ echo a > a
$ hg add a
$ cd ..
$ hg ci -qm 'hg add dir1/a'
$ hg up -q '.^'
$ hg mv -q dir1 dir2
$ hg ci -qm 'mv dir1 dir2'
$ hg log -G -T 'changeset {node}\n desc {desc}, phase: {phase}\n'
@ changeset e8919e7df8d036e07b906045eddcd4a42ff1915f
| desc mv dir1 dir2, phase: draft
| o changeset 7c7c6f339be00f849c3cb2df738ca91db78b32c8
|/ desc hg add dir1/a, phase: draft
o changeset a235dcce55dcf42034c4e374cb200662d0bb4a13
desc initial, phase: draft
$ hg rebase -s . -d 1 --config experimental.copytrace.sourcecommitlimit=100
rebasing 2:e8919e7df8d0 "mv dir1 dir2" (tip)
saved backup bundle to $TESTTMP/repo/repo/.hg/strip-backup/e8919e7df8d0-f62fab62-rebase.hg
$ ls dir2
a
dummy
$ rm -rf repo
Testing the sourcecommitlimit config
-----------------------------------
$ hg init repo
$ initclient repo
$ cd repo
$ echo a > a
$ hg ci -Aqm "added a"
$ echo "more things" >> a
$ hg ci -qm "added more things to a"
$ hg up 0
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ echo b > b
$ hg ci -Aqm "added b"
$ mkdir foo
$ hg mv a foo/bar
$ hg ci -m "Moved a to foo/bar"
$ hg log -G -T 'changeset {node}\n desc {desc}, phase: {phase}\n'
@ changeset b4b0f7880e500b5c364a5f07b4a2b167de7a6fb0
| desc Moved a to foo/bar, phase: draft
o changeset 5f6d8a4bf34ab274ccc9f631c2536964b8a3666d
| desc added b, phase: draft
| o changeset 8b6e13696c38e8445a759516474640c2f8dddef6
|/ desc added more things to a, phase: draft
o changeset 9092f1db7931481f93b37d5c9fbcfc341bcd7318
desc added a, phase: draft
When the sourcecommitlimit is small and we have more drafts, we use heuristics only
$ hg rebase -s 8b6e13696 -d .
rebasing 1:8b6e13696c38 "added more things to a"
other [source] changed a which local [dest] deleted
use (c)hanged version, leave (d)eleted, or leave (u)nresolved? u
unresolved conflicts (see hg resolve, then hg rebase --continue)
[1]
But when we have "sourcecommitlimit > (no. of drafts from base to c1)", we do
fullcopytracing
$ hg rebase --abort
rebase aborted
$ hg rebase -s 8b6e13696 -d . --config experimental.copytrace.sourcecommitlimit=100
rebasing 1:8b6e13696c38 "added more things to a"
merging foo/bar and a to foo/bar
saved backup bundle to $TESTTMP/repo/repo/repo/.hg/strip-backup/8b6e13696c38-fc14ac83-rebase.hg
$ cd ..
$ rm -rf repo