procutil: make stream detection in make_line_buffered more correct and strict
In make_line_buffered(), we don’t want to wrap the stream if we know that lines
get flushed to the underlying raw stream already.
Previously, the heuristic was too optimistic. It assumed that any stream which
is not an instance of io.BufferedIOBase doesn’t need wrapping. However, there
are buffered streams that aren’t instances of io.BufferedIOBase, like
Mercurial’s own winstdout.
The new logic is different in two ways:
First, only for the check, if unwraps any combination of WriteAllWrapper and
winstdout.
Second, it skips wrapping the stream only if it is an instance of io.RawIOBase
(or already wrapped). If it is an instance of io.BufferedIOBase, it gets
wrapped. In any other case, the function raises an exception. This ensures
that, if an unknown stream is passed or we add another wrapper in the future,
we don’t wrap the stream if it’s already line buffered or not wrap the stream
if it’s not line buffered. In fact, this was already helpful during development
of this change. Without it, I possibly would have forgot that WriteAllWrapper
needs to be ignored for the check, leading to unnecessary wrapping if stdout is
unbuffered.
The alternative would have been to always wrap unknown streams. However, I
don’t think that anyone would benefit from being less strict. We can expect
streams from the standard library to be subclassing either io.RawIOBase or
io.BufferedIOBase, so running Mercurial in the standard way should not regress
by this change. Py2exe might replace sys.stdout and sys.stderr, but that
currently breaks Mercurial anyway and also these streams don’t claim to be
interactive, so this function is not called for them.
$ cat >> $HGRCPATH <<EOF
> [experimental]
> bundle-phases=yes
> [extensions]
> strip=
> drawdag=$TESTDIR/drawdag.py
> EOF
Set up repo with linear history
$ hg init linear
$ cd linear
$ hg debugdrawdag <<'EOF'
> E
> |
> D
> |
> C
> |
> B
> |
> A
> EOF
$ hg phase --public A
$ hg phase --force --secret D
$ hg log -G -T '{desc} {phase}\n'
o E secret
|
o D secret
|
o C draft
|
o B draft
|
o A public
Phases are restored when unbundling
$ hg bundle --base B -r E bundle
3 changesets found
$ hg debugbundle bundle
Stream params: {Compression: BZ}
changegroup -- {nbchanges: 3, targetphase: 2, version: 02} (mandatory: True)
26805aba1e600a82e93661149f2313866a221a7b
f585351a92f85104bff7c284233c338b10eb1df7
9bc730a19041f9ec7cb33c626e811aa233efb18c
cache:rev-branch-cache -- {} (mandatory: False)
phase-heads -- {} (mandatory: True)
26805aba1e600a82e93661149f2313866a221a7b draft
$ hg strip --no-backup C
$ hg unbundle -q bundle
$ rm bundle
$ hg log -G -T '{desc} {phase}\n'
o E secret
|
o D secret
|
o C draft
|
o B draft
|
o A public
Root revision's phase is preserved
$ hg bundle -a bundle
5 changesets found
$ hg strip --no-backup A
$ hg unbundle -q bundle
$ rm bundle
$ hg log -G -T '{desc} {phase}\n'
o E secret
|
o D secret
|
o C draft
|
o B draft
|
o A public
Completely public history can be restored
$ hg phase --public E
$ hg bundle -a bundle
5 changesets found
$ hg strip --no-backup A
$ hg unbundle -q bundle
$ rm bundle
$ hg log -G -T '{desc} {phase}\n'
o E public
|
o D public
|
o C public
|
o B public
|
o A public
Direct transition from public to secret can be restored
$ hg phase --secret --force D
$ hg bundle -a bundle
5 changesets found
$ hg strip --no-backup A
$ hg unbundle -q bundle
$ rm bundle
$ hg log -G -T '{desc} {phase}\n'
o E secret
|
o D secret
|
o C public
|
o B public
|
o A public
Revisions within bundle preserve their phase even if parent changes its phase
$ hg phase --draft --force B
$ hg bundle --base B -r E bundle
3 changesets found
$ hg strip --no-backup C
$ hg phase --public B
$ hg unbundle -q bundle
$ rm bundle
$ hg log -G -T '{desc} {phase}\n'
o E secret
|
o D secret
|
o C draft
|
o B public
|
o A public
Phase of ancestors of stripped node get advanced to accommodate child
$ hg bundle --base B -r E bundle
3 changesets found
$ hg strip --no-backup C
$ hg phase --force --secret B
$ hg unbundle -q bundle
$ rm bundle
$ hg log -G -T '{desc} {phase}\n'
o E secret
|
o D secret
|
o C draft
|
o B draft
|
o A public
Unbundling advances phases of changesets even if they were already in the repo.
To test that, create a bundle of everything in draft phase and then unbundle
to see that secret becomes draft, but public remains public.
$ hg phase --draft --force A
$ hg phase --draft E
$ hg bundle -a bundle
5 changesets found
$ hg phase --public A
$ hg phase --secret --force E
$ hg unbundle -q bundle
$ rm bundle
$ hg log -G -T '{desc} {phase}\n'
o E draft
|
o D draft
|
o C draft
|
o B draft
|
o A public
Unbundling change in the middle of a stack does not affect later changes
$ hg strip --no-backup E
$ hg phase --secret --force D
$ hg log -G -T '{desc} {phase}\n'
o D secret
|
o C draft
|
o B draft
|
o A public
$ hg bundle --base A -r B bundle
1 changesets found
$ hg unbundle -q bundle
$ rm bundle
$ hg log -G -T '{desc} {phase}\n'
o D secret
|
o C draft
|
o B draft
|
o A public
$ cd ..
Set up repo with non-linear history
$ hg init non-linear
$ cd non-linear
$ hg debugdrawdag <<'EOF'
> D E
> |\|
> B C
> |/
> A
> EOF
$ hg phase --public C
$ hg phase --force --secret B
$ hg log -G -T '{node|short} {desc} {phase}\n'
o 03ca77807e91 E draft
|
| o 4e4f9194f9f1 D secret
|/|
o | dc0947a82db8 C public
| |
| o 112478962961 B secret
|/
o 426bada5c675 A public
Restore bundle of entire repo
$ hg bundle -a bundle
5 changesets found
$ hg debugbundle bundle
Stream params: {Compression: BZ}
changegroup -- {nbchanges: 5, targetphase: 2, version: 02} (mandatory: True)
426bada5c67598ca65036d57d9e4b64b0c1ce7a0
112478962961147124edd43549aedd1a335e44bf
dc0947a82db884575bb76ea10ac97b08536bfa03
4e4f9194f9f181c57f62e823e8bdfa46ab9e4ff4
03ca77807e919db8807c3749086dc36fb478cac0
cache:rev-branch-cache -- {} (mandatory: False)
phase-heads -- {} (mandatory: True)
dc0947a82db884575bb76ea10ac97b08536bfa03 public
03ca77807e919db8807c3749086dc36fb478cac0 draft
$ hg strip --no-backup A
$ hg unbundle -q bundle
$ rm bundle
$ hg log -G -T '{node|short} {desc} {phase}\n'
o 03ca77807e91 E draft
|
| o 4e4f9194f9f1 D secret
|/|
o | dc0947a82db8 C public
| |
| o 112478962961 B secret
|/
o 426bada5c675 A public
$ hg bundle --base 'A + C' -r D bundle
2 changesets found
$ hg debugbundle bundle
Stream params: {Compression: BZ}
changegroup -- {nbchanges: 2, targetphase: 2, version: 02} (mandatory: True)
112478962961147124edd43549aedd1a335e44bf
4e4f9194f9f181c57f62e823e8bdfa46ab9e4ff4
cache:rev-branch-cache -- {} (mandatory: False)
phase-heads -- {} (mandatory: True)
$ rm bundle
$ hg bundle --base A -r D bundle
3 changesets found
$ hg debugbundle bundle
Stream params: {Compression: BZ}
changegroup -- {nbchanges: 3, targetphase: 2, version: 02} (mandatory: True)
112478962961147124edd43549aedd1a335e44bf
dc0947a82db884575bb76ea10ac97b08536bfa03
4e4f9194f9f181c57f62e823e8bdfa46ab9e4ff4
cache:rev-branch-cache -- {} (mandatory: False)
phase-heads -- {} (mandatory: True)
dc0947a82db884575bb76ea10ac97b08536bfa03 public
$ rm bundle
$ hg bundle --base 'B + C' -r 'D + E' bundle
2 changesets found
$ hg debugbundle bundle
Stream params: {Compression: BZ}
changegroup -- {nbchanges: 2, targetphase: 2, version: 02} (mandatory: True)
4e4f9194f9f181c57f62e823e8bdfa46ab9e4ff4
03ca77807e919db8807c3749086dc36fb478cac0
cache:rev-branch-cache -- {} (mandatory: False)
phase-heads -- {} (mandatory: True)
03ca77807e919db8807c3749086dc36fb478cac0 draft
$ rm bundle