view tests/test-audit-path.t @ 44950:f9734b2d59cc

py3: make stdout line-buffered if connected to a TTY Status messages that are to be shown on the terminal should be written to the file descriptor before anything further is done, to keep the user updated. One common way to achieve this is to make stdout line-buffered if it is connected to a TTY. This is done on Python 2 (except on Windows, where libc, which the CPython 2 streams depend on, does not properly support this). Python 3 rolls it own I/O streams. On Python 3, buffered binary streams can't be set line-buffered. The previous code (added in 227ba1afcb65) incorrectly assumed that on Python 3, pycompat.stdout (sys.stdout.buffer) is already line-buffered. However the interpreter initializes it with a block-buffered stream or an unbuffered stream (when the -u option or the PYTHONUNBUFFERED environment variable is set), never with a line-buffered stream. One example where the current behavior is unacceptable is when running `hg pull https://www.mercurial-scm.org/repo/hg` on Python 3, where the line "pulling from https://www.mercurial-scm.org/repo/hg" does not appear on the terminal before the hg process blocks while waiting for the server. Various approaches to fix this problem are possible, including: 1. Weaken the contract of procutil.stdout to not give any guarantees about buffering behavior. In this case, users of procutil.stdout need to be changed to do enough flushes. In particular, 1. either ui must insert enough flushes for ui.write() and friends, or 2. ui.write() and friends get split into flushing and fully buffered methods, or 3. users of ui.write() and friends must flush explicitly. 2. Make stdout unbuffered. 3. Make stdout line-buffered. Since Python 3 does not natively support that for binary streams, we must implement it ourselves. (2.) is problematic because using unbuffered I/O changes the performance characteristics significantly compared to line-buffered (which is used on Python 2) and this would be a regression. (1.2.) and (1.3) are a substantial amount of work. It’s unclear whether the added complexity would be justified, given that raw performance doesn’t matter that much when writing to a terminal much faster than the user could read it. (1.1.) pushes complexity into the ui class instead of separating the concern of how stdout is buffered. Other users of procutil.stdout would still need to take care of the flushes. This patch implements (3.). The general performance considerations are very similar to (1.1.). The extra method invocation and method forwarding add a little more overhead if the class is used. In exchange, it doesn’t add overhead if not used. For the benchmarks, I compared the previous implementation (incorrect on Python 3), (1.1.), (3.) and (2.). The command was chosen so that the streams were configured as if they were writing to a TTY, but actually write to a pager, which is also the default: HGRCPATH=/dev/null python3 ./hg --cwd ~/vcs/mozilla-central --time --pager yes --config pager.pager='cat > /dev/null' status --all previous: time: real 7.880 secs (user 7.290+0.050 sys 0.580+0.170) time: real 7.830 secs (user 7.220+0.070 sys 0.590+0.140) time: real 7.800 secs (user 7.210+0.050 sys 0.570+0.170) (1.1.) using Yuya Nishihara’s patch: time: real 9.860 secs (user 8.670+0.350 sys 1.160+0.830) time: real 9.540 secs (user 8.430+0.370 sys 1.100+0.770) time: real 9.830 secs (user 8.630+0.370 sys 1.180+0.840) (3.) using this patch: time: real 9.580 secs (user 8.480+0.350 sys 1.090+0.770) time: real 9.670 secs (user 8.480+0.330 sys 1.170+0.860) time: real 9.640 secs (user 8.500+0.350 sys 1.130+0.810) (2.) using a previous patch by me: time: real 10.480 secs (user 8.850+0.720 sys 1.590+1.500) time: real 10.490 secs (user 8.750+0.750 sys 1.710+1.470) time: real 10.240 secs (user 8.600+0.700 sys 1.590+1.510) As expected, there’s no difference on Python 2, as exactly the same code paths are used: previous: time: real 6.950 secs (user 5.870+0.330 sys 1.070+0.770) time: real 7.040 secs (user 6.040+0.360 sys 0.980+0.750) time: real 7.070 secs (user 5.950+0.360 sys 1.100+0.760) this patch: time: real 7.010 secs (user 5.900+0.390 sys 1.070+0.730) time: real 7.000 secs (user 5.850+0.350 sys 1.120+0.760) time: real 7.000 secs (user 5.790+0.380 sys 1.170+0.710)
author Manuel Jacob <me@manueljacob.de>
date Wed, 10 Jun 2020 13:02:39 +0200
parents 89630d0b3e23
children f90a5c211251
line wrap: on
line source

The simple store doesn't escape paths robustly and can't store paths
with periods, etc. So much of this test fails with it.
#require no-reposimplestore

  $ hg init

audit of .hg

  $ hg add .hg/00changelog.i
  abort: path contains illegal component: .hg/00changelog.i
  [255]

#if symlink

Symlinks

  $ mkdir a
  $ echo a > a/a
  $ hg ci -Ama
  adding a/a
  $ ln -s a b
  $ echo b > a/b
  $ hg add b/b
  abort: path 'b/b' traverses symbolic link 'b'
  [255]
  $ hg add b

should still fail - maybe

  $ hg add b/b
  abort: path 'b/b' traverses symbolic link 'b'
  [255]

  $ hg commit -m 'add symlink b'


Test symlink traversing when accessing history:
-----------------------------------------------

(build a changeset where the path exists as a directory)

  $ hg up 0
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ mkdir b
  $ echo c > b/a
  $ hg add b/a
  $ hg ci -m 'add directory b'
  created new head

Test that hg cat does not do anything wrong the working copy has 'b' as directory

  $ hg cat b/a
  c
  $ hg cat -r "desc(directory)" b/a
  c
  $ hg cat -r "desc(symlink)" b/a
  b/a: no such file in rev bc151a1f53bd
  [1]

Test that hg cat does not do anything wrong the working copy has 'b' as a symlink (issue4749)

  $ hg up 'desc(symlink)'
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ hg cat b/a
  b/a: no such file in rev bc151a1f53bd
  [1]
  $ hg cat -r "desc(directory)" b/a
  c
  $ hg cat -r "desc(symlink)" b/a
  b/a: no such file in rev bc151a1f53bd
  [1]

#endif


unbundle tampered bundle

  $ hg init target
  $ cd target
  $ hg unbundle "$TESTDIR/bundles/tampered.hg"
  adding changesets
  adding manifests
  adding file changes
  added 5 changesets with 6 changes to 6 files (+4 heads)
  new changesets b7da9bf6b037:fc1393d727bc (5 drafts)
  (run 'hg heads' to see heads, 'hg merge' to merge)

attack .hg/test

  $ hg manifest -r0
  .hg/test
  $ hg update -Cr0
  abort: path contains illegal component: .hg/test
  [255]

attack foo/.hg/test

  $ hg manifest -r1
  foo/.hg/test
  $ hg update -Cr1
  abort: path 'foo/.hg/test' is inside nested repo 'foo'
  [255]

attack back/test where back symlinks to ..

  $ hg manifest -r2
  back
  back/test
#if symlink
  $ hg update -Cr2
  abort: path 'back/test' traverses symbolic link 'back'
  [255]
#else
('back' will be a file and cause some other system specific error)
  $ hg update -Cr2
  abort: $TESTTMP/target/back/test: $ENOTDIR$
  [255]
#endif

attack ../test

  $ hg manifest -r3
  ../test
  $ mkdir ../test
  $ echo data > ../test/file
  $ hg update -Cr3
  abort: path contains illegal component: ../test
  [255]
  $ cat ../test/file
  data

attack /tmp/test

  $ hg manifest -r4
  /tmp/test
  $ hg update -Cr4
  abort: path contains illegal component: /tmp/test
  [255]

  $ cd ..

Test symlink traversal on merge:
--------------------------------

#if symlink

set up symlink hell

  $ mkdir merge-symlink-out
  $ hg init merge-symlink
  $ cd merge-symlink
  $ touch base
  $ hg commit -qAm base
  $ ln -s ../merge-symlink-out a
  $ hg commit -qAm 'symlink a -> ../merge-symlink-out'
  $ hg up -q 0
  $ mkdir a
  $ touch a/poisoned
  $ hg commit -qAm 'file a/poisoned'
  $ hg log -G -T '{rev}: {desc}\n'
  @  2: file a/poisoned
  |
  | o  1: symlink a -> ../merge-symlink-out
  |/
  o  0: base
  

try trivial merge

  $ hg up -qC 1
  $ hg merge 2
  abort: path 'a/poisoned' traverses symbolic link 'a'
  [255]

try rebase onto other revision: cache of audited paths should be discarded,
and the rebase should fail (issue5628)

  $ hg up -qC 2
  $ hg rebase -s 2 -d 1 --config extensions.rebase=
  rebasing 2:e73c21d6b244 "file a/poisoned" (tip)
  abort: path 'a/poisoned' traverses symbolic link 'a'
  [255]
  $ ls ../merge-symlink-out

  $ cd ..

Test symlink traversal on update:
---------------------------------

  $ mkdir update-symlink-out
  $ hg init update-symlink
  $ cd update-symlink
  $ ln -s ../update-symlink-out a
  $ hg commit -qAm 'symlink a -> ../update-symlink-out'
  $ hg rm a
  $ mkdir a && touch a/b
  $ hg ci -qAm 'file a/b' a/b
  $ hg up -qC 0
  $ hg rm a
  $ mkdir a && touch a/c
  $ hg ci -qAm 'rm a, file a/c'
  $ hg log -G -T '{rev}: {desc}\n'
  @  2: rm a, file a/c
  |
  | o  1: file a/b
  |/
  o  0: symlink a -> ../update-symlink-out
  

try linear update where symlink already exists:

  $ hg up -qC 0
  $ hg up 1
  abort: path 'a/b' traverses symbolic link 'a'
  [255]

try linear update including symlinked directory and its content: paths are
audited first by calculateupdates(), where no symlink is created so both
'a' and 'a/b' are taken as good paths. still applyupdates() should fail.

  $ hg up -qC null
  $ hg up 1
  abort: path 'a/b' traverses symbolic link 'a'
  [255]
  $ ls ../update-symlink-out

try branch update replacing directory with symlink, and its content: the
path 'a' is audited as a directory first, which should be audited again as
a symlink.

  $ rm -f a
  $ hg up -qC 2
  $ hg up 1
  abort: path 'a/b' traverses symbolic link 'a'
  [255]
  $ ls ../update-symlink-out

  $ cd ..

#endif