view tests/test-transaction-safety.t @ 47315:825d5a5907b4

exewrapper: avoid directly linking against python3X.dll

Subsequent code calls `LoadLibrary()` to attempt to load the DLL, but because of
this symbol reference, there is an attempt to load the DLL used during the build
prior to `_main()` running.  This causes the whole process to fail if the DLL
isn't in the standard search path.  That also means it will never load the DLL
for HackableMercurial.  (Maybe we should get rid of that for py3, since you can
install python for a user without admin rights?)

This could also be resolved by calling `GetProcAddress()` on the symbol and
dereferencing it, but using the environment variable is consistent with the
*.bat file since fc8a5c9ecee0.  (The environment variable persists after the
interpreter is initialized.)

Far more concerning is somehow I've gotten my system into a state where setting
the flag causes any output to the pager to be lost (as if it wasn't set at all)
in MSYS, cmd.exe, WSL, and PowerShell using py3.9.0, but the environment
variable works properly.  I'm sure this flag worked on some versions of py3, so
I'm not sure what's going on here.  This is might be related to init config
related changes in 3.8[1], since it works with 3.7.8, but fails with 3.8.1.
Somebody who understands encoding issues better than I do should give some
thought to if we need to make some changes to our encoding strategy on Windows
with py3.

With or without the flag/envvar, there is proper output if the command is
directly paged by piping to `more.com` (in any environment) or `less` (in MSYS
and WSL), or if paging is disabled with `--pager=no`.  Legacy mode is required
though when Mercurial decides to spin up a pager.

[1] https://bugs.python.org/issue41941

Differential Revision: https://phab.mercurial-scm.org/D10756

Test transaction safety
=======================

#testcases revlogv1 revlogv2 changelogv2

#if revlogv1

  $ cat << EOF >> $HGRCPATH
  > [experimental]
  > revlogv2=no
  > EOF

#endif

#if revlogv2

  $ cat << EOF >> $HGRCPATH
  > [experimental]
  > revlogv2=enable-unstable-format-and-corrupt-my-data
  > EOF

#endif

#if changelogv2

  $ cat << EOF >> $HGRCPATH
  > [format]
  > exp-use-changelog-v2=enable-unstable-format-and-corrupt-my-data
  > EOF

#endif

This test basic case to make sure external process do not see transaction
content until it is committed.

# TODO: also add an external reader accessing revlog files while they are written
#       (instead of during transaction finalisation)

# TODO: also add stream clone and hardlink clone happening during these transaction.

setup
-----

synchronisation+output script:

  $ mkdir sync
  $ mkdir output
  $ mkdir script
  $ HG_TEST_FILE_EXT_WAITING=$TESTTMP/sync/ext_waiting
  $ export HG_TEST_FILE_EXT_WAITING
  $ HG_TEST_FILE_EXT_UNLOCK=$TESTTMP/sync/ext_unlock
  $ export HG_TEST_FILE_EXT_UNLOCK
  $ HG_TEST_FILE_EXT_DONE=$TESTTMP/sync/ext_done
  $ export HG_TEST_FILE_EXT_DONE
  $ cat << EOF > script/external.sh
  > #!/bin/sh
  > "$RUNTESTDIR/testlib/wait-on-file" 5 "$HG_TEST_FILE_EXT_UNLOCK" "$HG_TEST_FILE_EXT_WAITING"
  > hg log --rev 'tip' -T 'external: {rev} {desc}\n' > "$TESTTMP/output/external.out"
  > touch "$HG_TEST_FILE_EXT_DONE"
  > EOF
  $ cat << EOF > script/internal.sh
  > #!/bin/sh
  > hg log --rev 'tip' -T 'internal: {rev} {desc}\n' > "$TESTTMP/output/internal.out"
  > "$RUNTESTDIR/testlib/wait-on-file" 5 "$HG_TEST_FILE_EXT_DONE" "$HG_TEST_FILE_EXT_UNLOCK"
  > EOF


Automated commands:

  $ make_one_commit() {
  > rm -f $TESTTMP/sync/*
  > rm -f $TESTTMP/output/*
  > hg log --rev 'tip' -T 'pre-commit: {rev} {desc}\n'
  > echo x >> a
  > sh $TESTTMP/script/external.sh & hg commit -m "$1"
  > cat $TESTTMP/output/external.out
  > cat $TESTTMP/output/internal.out
  > hg log --rev 'tip' -T 'post-tr:  {rev} {desc}\n'
  > }


  $ make_one_pull() {
  > rm -f $TESTTMP/sync/*
  > rm -f $TESTTMP/output/*
  > hg log --rev 'tip' -T 'pre-commit: {rev} {desc}\n'
  > echo x >> a
  > sh $TESTTMP/script/external.sh & hg pull ../other-repo/ --rev "$1" --force --quiet
  > cat $TESTTMP/output/external.out
  > cat $TESTTMP/output/internal.out
  > hg log --rev 'tip' -T 'post-tr:  {rev} {desc}\n'
  > }

prepare a large source to which to pull from:

The source is large to unsure we don't use inline more after the pull

  $ hg init other-repo
  $ hg -R other-repo debugbuilddag .+500


prepare an empty repository where to make test:

  $ hg init repo
  $ cd repo
  $ touch a
  $ hg add a

prepare a small extension to controll inline size

  $ mkdir $TESTTMP/ext
  $ cat << EOF > $TESTTMP/ext/small_inline.py
  > from mercurial import revlog
  > revlog._maxinline = 64 * 100
  > EOF




  $ cat << EOF >> $HGRCPATH
  > [extensions]
  > small_inline=$TESTTMP/ext/small_inline.py
  > [hooks]
  > pretxnclose = sh $TESTTMP/script/internal.sh
  > EOF

check this is true for the initial commit (inline → inline)
-----------------------------------------------------------

the repository should still be inline (for relevant format)

  $ make_one_commit first
  pre-commit: -1 
  external: -1 
  internal: 0 first
  post-tr:  0 first

#if revlogv1

  $ hg debugrevlog -c | grep inline
  flags  : inline

#endif

check this is true for extra commit (inline → inline)
-----------------------------------------------------

the repository should still be inline (for relevant format)

#if revlogv1

  $ hg debugrevlog -c | grep inline
  flags  : inline

#endif

  $ make_one_commit second
  pre-commit: 0 first
  external: 0 first
  internal: 1 second
  post-tr:  1 second

#if revlogv1

  $ hg debugrevlog -c | grep inline
  flags  : inline

#endif

check this is true for a small pull (inline → inline)
-----------------------------------------------------

the repository should still be inline (for relevant format)

#if revlogv1

  $ hg debugrevlog -c | grep inline
  flags  : inline

#endif

  $ make_one_pull 3
  pre-commit: 1 second
  warning: repository is unrelated
  external: 1 second
  internal: 5 r3
  post-tr:  5 r3

#if revlogv1

  $ hg debugrevlog -c | grep inline
  flags  : inline

#endif

Make a large pull (inline → no-inline)
---------------------------------------

the repository should no longer be inline (for relevant format)

#if revlogv1

  $ hg debugrevlog -c | grep inline
  flags  : inline

#endif

  $ make_one_pull 400
  pre-commit: 5 r3
  external: 5 r3
  internal: 402 r400
  post-tr:  402 r400

#if revlogv1

  $ hg debugrevlog -c | grep inline
  [1]

#endif

check this is true for extra commit (no-inline → no-inline)
-----------------------------------------------------------

the repository should no longer be inline (for relevant format)

#if revlogv1

  $ hg debugrevlog -c | grep inline
  [1]

#endif

  $ make_one_commit third
  pre-commit: 402 r400
  external: 402 r400
  internal: 403 third
  post-tr:  403 third

#if revlogv1

  $ hg debugrevlog -c | grep inline
  [1]

#endif


Make a  pull (not-inline → no-inline)
-------------------------------------

the repository should no longer be inline (for relevant format)

#if revlogv1

  $ hg debugrevlog -c | grep inline
  [1]

#endif

  $ make_one_pull tip
  pre-commit: 403 third
  external: 403 third
  internal: 503 r500
  post-tr:  503 r500

#if revlogv1

  $ hg debugrevlog -c | grep inline
  [1]

#endif