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view tests/test-narrow-pull.t @ 42752:30320c7bf79f
rust-cpython: add macro for sharing references
Following an experiment done by Georges Racinet, we now have a working way of
sharing references between Python and Rust. This is needed in many points of
the codebase, for example every time we need to expose an iterator to a
Rust-backed Python class.
In a few words, references are (unsafely) marked as `'static` and coupled
with manual reference counting; we are doing manual borrow-checking.
This changes introduces two declarative macro to help reduce boilerplate.
While it is better than not using macros, they are not perfect. They need to:
- Integrate with the garbage collector for container types (not needed
as of yet), as stated in the docstring
- Allow for leaking multiple attributes at the same time
- Inject the `py_shared_state` data attribute in `py_class`-generated
structs
- Automatically namespace the functions and attributes they generate
For at least the last two points, we will need to write a procedural macro
instead of a declarative one.
While this reference-sharing mechanism is being ironed out I thought it best
not to implement it yet.
Lastly, and implementation detail renders our Rust-backed Python iterators too
strict to be proper drop-in replacements, as will be illustrated in a future
patch: if the data structure referenced by a non-depleted iterator is mutated,
an `AlreadyBorrowed` exception is raised, whereas Python would allow it, only
to raise a `RuntimeError` if `next` is called on said iterator. This will have
to be addressed at some point.
Differential Revision: https://phab.mercurial-scm.org/D6631
author | Raphaël Gomès <rgomes@octobus.net> |
---|---|
date | Tue, 09 Jul 2019 15:15:54 +0200 |
parents | 7db1619af061 |
children | 5c2a4f37eace |
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$ . "$TESTDIR/narrow-library.sh" $ hg init master $ cd master $ cat >> .hg/hgrc <<EOF > [narrow] > serveellipses=True > EOF $ for x in `$TESTDIR/seq.py 10` > do > echo $x > "f$x" > hg add "f$x" > hg commit -m "Commit f$x" > done $ cd .. narrow clone a couple files, f2 and f8 $ hg clone --narrow ssh://user@dummy/master narrow --include "f2" --include "f8" requesting all changes adding changesets adding manifests adding file changes added 5 changesets with 2 changes to 2 files new changesets *:* (glob) updating to branch default 2 files updated, 0 files merged, 0 files removed, 0 files unresolved $ cd narrow $ ls f2 f8 $ cat f2 f8 2 8 $ cd .. change every upstream file twice $ cd master $ for x in `$TESTDIR/seq.py 10` > do > echo "update#1 $x" >> "f$x" > hg commit -m "Update#1 to f$x" "f$x" > done $ for x in `$TESTDIR/seq.py 10` > do > echo "update#2 $x" >> "f$x" > hg commit -m "Update#2 to f$x" "f$x" > done $ cd .. look for incoming changes $ cd narrow $ hg incoming --limit 3 comparing with ssh://user@dummy/master searching for changes changeset: 5:ddc055582556 user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: Update#1 to f1 changeset: 6:f66eb5ad621d user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: Update#1 to f2 changeset: 7:c42ecff04e99 user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: Update#1 to f3 Interrupting the pull is safe $ hg --config hooks.pretxnchangegroup.bad=false pull -q transaction abort! rollback completed abort: pretxnchangegroup.bad hook exited with status 1 [255] $ hg id 223311e70a6f tip pull new changes down to the narrow clone. Should get 8 new changesets: 4 relevant to the narrow spec, and 4 ellipsis nodes gluing them all together. $ hg pull pulling from ssh://user@dummy/master searching for changes adding changesets adding manifests adding file changes added 9 changesets with 4 changes to 2 files new changesets *:* (glob) (run 'hg update' to get a working copy) $ hg log -T '{rev}: {desc}\n' 13: Update#2 to f10 12: Update#2 to f8 11: Update#2 to f7 10: Update#2 to f2 9: Update#2 to f1 8: Update#1 to f8 7: Update#1 to f7 6: Update#1 to f2 5: Update#1 to f1 4: Commit f10 3: Commit f8 2: Commit f7 1: Commit f2 0: Commit f1 $ hg update tip 2 files updated, 0 files merged, 0 files removed, 0 files unresolved add a change and push it $ echo "update#3 2" >> f2 $ hg commit -m "Update#3 to f2" f2 $ hg log f2 -T '{rev}: {desc}\n' 14: Update#3 to f2 10: Update#2 to f2 6: Update#1 to f2 1: Commit f2 $ hg push pushing to ssh://user@dummy/master searching for changes remote: adding changesets remote: adding manifests remote: adding file changes remote: added 1 changesets with 1 changes to 1 files $ cd .. $ cd master $ hg log f2 -T '{rev}: {desc}\n' 30: Update#3 to f2 21: Update#2 to f2 11: Update#1 to f2 1: Commit f2 $ hg log -l 3 -T '{rev}: {desc}\n' 30: Update#3 to f2 29: Update#2 to f10 28: Update#2 to f9 Can pull into repo with a single commit $ cd .. $ hg clone -q --narrow ssh://user@dummy/master narrow2 --include "f1" -r 0 $ cd narrow2 $ hg pull -q -r 1 transaction abort! rollback completed abort: pull failed on remote [255]