view tests/test-mq-qnew.t @ 46607:e9901d01d135

revlog: add a mechanism to verify expected file position before appending

If someone uses `hg debuglocks`, or some non-hg process writes to the .hg
directory without respecting the locks, or if the repo's on a networked
filesystem, it's possible for the revlog code to write out corrupted data.

The form of this corruption can vary depending on what data was written and how
that happened. We are in the "networked filesystem" case (though I've had users
also do this to themselves with the "`hg debuglocks`" scenario), and most often
see this with the changelog. What ends up happening is we produce two items
(let's call them rev1 and rev2) in the .i file that have the same linkrev,
baserev, and offset into the .d file, while the data in the .d file is appended
properly. rev2's compressed_size is accurate for rev2, but when we go to
decompress the data in the .d file, we use the offset that's recorded in the
index file, which is the same as rev1, and attempt to decompress
rev2.compressed_size bytes of rev1's data. This usually does not succeed. :)

When using inline data, this also fails, though I haven't investigated why too
closely. This shows up as a "patch decode" error. I believe what's happening
there is that we're basically ignoring the offset field, getting the data
properly, but since baserev != rev, it thinks this is a delta based on rev
(instead of a full text) and can't actually apply it as such.

For now, I'm going to make this an optional component and default it to entirely
off. I may increase the default severity of this in the future, once I've
enabled it for my users and we gain more experience with it. Luckily, most of my
users have a versioned filesystem and can roll back to before the corruption has
been written, it's just a hassle to do so and not everyone knows how (so it's a
support burden). Users on other filesystems will not have that luxury, and this
can cause them to have a corrupted repository that they are unlikely to know how
to resolve, and they'll see this as a data-loss event. Refusing to create the
corruption is a much better user experience.

This mechanism is not perfect. There may be false-negatives (racy writes that
are not detected). There should not be any false-positives (non-racy writes that
are detected as such). This is not a mechanism that makes putting a repo on a
networked filesystem "safe" or "supported", just *less* likely to cause
corruption.

Differential Revision: https://phab.mercurial-scm.org/D9952

  $ catpatch() {
  >     cat $1 | sed -e "s/^\(# Parent \).*/\1/"
  > }
  $ echo "[extensions]" >> $HGRCPATH
  $ echo "mq=" >> $HGRCPATH
  $ runtest() {
  >     hg init mq
  >     cd mq
  > 
  >     echo a > a
  >     hg ci -Ama
  > 
  >     echo '% qnew should refuse bad patch names'
  >     hg qnew series
  >     hg qnew status
  >     hg qnew guards
  >     hg qnew .
  >     hg qnew ..
  >     hg qnew .hgignore
  >     hg qnew .mqfoo
  >     hg qnew 'foo#bar'
  >     hg qnew 'foo:bar'
  >     hg qnew "`echo foo; echo bar`"
  >     hg qnew ' foo'
  >     hg qnew 'foo '
  > 
  >     hg qinit -c
  > 
  >     echo '% qnew with name containing slash'
  >     hg qnew foo/
  >     hg qnew foo/bar.patch
  >     hg qnew foo
  >     hg qseries
  >     hg qpop
  >     hg qdelete foo/bar.patch
  > 
  >     echo '% qnew with uncommitted changes'
  >     echo a > somefile
  >     hg add somefile
  >     hg qnew uncommitted.patch
  >     hg st
  >     hg qseries
  > 
  >     echo '% qnew implies add'
  >     hg -R .hg/patches st
  > 
  >     echo '% qnew missing'
  >     hg qnew missing.patch missing
  > 
  >     echo '% qnew -m'
  >     hg qnew -m 'foo bar' mtest.patch
  >     catpatch .hg/patches/mtest.patch
  > 
  >     echo '% qnew twice'
  >     hg qnew first.patch
  >     hg qnew first.patch
  > 
  >     touch ../first.patch
  >     hg qimport ../first.patch
  > 
  >     echo '% qnew -f from a subdirectory'
  >     hg qpop -a
  >     mkdir d
  >     cd d
  >     echo b > b
  >     hg ci -Am t
  >     echo b >> b
  >     hg st
  >     hg qnew -g -f p
  >     catpatch ../.hg/patches/p
  > 
  >     echo '% qnew -u with no username configured'
  >     HGUSER= hg qnew -u blue red
  >     catpatch ../.hg/patches/red
  > 
  >     echo '% qnew -e -u with no username configured'
  >     HGUSER= hg qnew -e -u chartreuse fucsia
  >     catpatch ../.hg/patches/fucsia
  > 
  >     echo '% fail when trying to import a merge'
  >     hg init merge
  >     cd merge
  >     touch a
  >     hg ci -Am null
  >     echo a >> a
  >     hg ci -m a
  >     hg up -r 0
  >     echo b >> a
  >     hg ci -m b
  >     hg merge -f 1
  >     hg resolve --mark a
  >     hg qnew -f merge
  > 
  >     cd ../../..
  >     rm -r mq
  > }

plain headers

  $ echo "[mq]" >> $HGRCPATH
  $ echo "plain=true" >> $HGRCPATH
  $ mkdir sandbox
  $ (cd sandbox ; runtest)
  adding a
  % qnew should refuse bad patch names
  abort: "series" cannot be used as the name of a patch
  abort: "status" cannot be used as the name of a patch
  abort: "guards" cannot be used as the name of a patch
  abort: "." cannot be used as the name of a patch
  abort: ".." cannot be used as the name of a patch
  abort: patch name cannot begin with ".hg"
  abort: patch name cannot begin with ".mq"
  abort: '#' cannot be used in the name of a patch
  abort: ':' cannot be used in the name of a patch
  abort: '\n' cannot be used in the name of a patch
  abort: patch name cannot begin or end with whitespace
  abort: patch name cannot begin or end with whitespace
  % qnew with name containing slash
  abort: path ends in directory separator: foo/
  abort: "foo" already exists as a directory
  foo/bar.patch
  popping foo/bar.patch
  patch queue now empty
  % qnew with uncommitted changes
  uncommitted.patch
  % qnew implies add
  A .hgignore
  A series
  A uncommitted.patch
  % qnew missing
  abort: missing: * (glob)
  % qnew -m
  foo bar
  
  % qnew twice
  abort: patch "first.patch" already exists
  abort: patch "first.patch" already exists
  % qnew -f from a subdirectory
  popping first.patch
  popping mtest.patch
  popping uncommitted.patch
  patch queue now empty
  adding d/b
  M d/b
  diff --git a/d/b b/d/b
  --- a/d/b
  +++ b/d/b
  @@ -1,1 +1,2 @@
   b
  +b
  % qnew -u with no username configured
  From: blue
  
  % qnew -e -u with no username configured
  From: chartreuse
  
  % fail when trying to import a merge
  adding a
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  created new head
  merging a
  warning: conflicts while merging a! (edit, then use 'hg resolve --mark')
  0 files updated, 0 files merged, 0 files removed, 1 files unresolved
  use 'hg resolve' to retry unresolved file merges or 'hg merge --abort' to abandon
  (no more unresolved files)
  abort: cannot manage merge changesets
  $ rm -r sandbox

hg headers

  $ echo "plain=false" >> $HGRCPATH
  $ mkdir sandbox
  $ (cd sandbox ; runtest)
  adding a
  % qnew should refuse bad patch names
  abort: "series" cannot be used as the name of a patch
  abort: "status" cannot be used as the name of a patch
  abort: "guards" cannot be used as the name of a patch
  abort: "." cannot be used as the name of a patch
  abort: ".." cannot be used as the name of a patch
  abort: patch name cannot begin with ".hg"
  abort: patch name cannot begin with ".mq"
  abort: '#' cannot be used in the name of a patch
  abort: ':' cannot be used in the name of a patch
  abort: '\n' cannot be used in the name of a patch
  abort: patch name cannot begin or end with whitespace
  abort: patch name cannot begin or end with whitespace
  % qnew with name containing slash
  abort: path ends in directory separator: foo/
  abort: "foo" already exists as a directory
  foo/bar.patch
  popping foo/bar.patch
  patch queue now empty
  % qnew with uncommitted changes
  uncommitted.patch
  % qnew implies add
  A .hgignore
  A series
  A uncommitted.patch
  % qnew missing
  abort: missing: * (glob)
  % qnew -m
  # HG changeset patch
  # Parent 
  foo bar
  
  % qnew twice
  abort: patch "first.patch" already exists
  abort: patch "first.patch" already exists
  % qnew -f from a subdirectory
  popping first.patch
  popping mtest.patch
  popping uncommitted.patch
  patch queue now empty
  adding d/b
  M d/b
  # HG changeset patch
  # Parent 
  
  diff --git a/d/b b/d/b
  --- a/d/b
  +++ b/d/b
  @@ -1,1 +1,2 @@
   b
  +b
  % qnew -u with no username configured
  # HG changeset patch
  # User blue
  # Parent 
  
  % qnew -e -u with no username configured
  # HG changeset patch
  # User chartreuse
  # Parent 
  
  % fail when trying to import a merge
  adding a
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  created new head
  merging a
  warning: conflicts while merging a! (edit, then use 'hg resolve --mark')
  0 files updated, 0 files merged, 0 files removed, 1 files unresolved
  use 'hg resolve' to retry unresolved file merges or 'hg merge --abort' to abandon
  (no more unresolved files)
  abort: cannot manage merge changesets
  $ rm -r sandbox

Test saving last-message.txt

  $ hg init repo
  $ cd repo

  $ cat > $TESTTMP/commitfailure.py <<EOF
  > from mercurial import error
  > def reposetup(ui, repo):
  >     class commitfailure(repo.__class__):
  >         def commit(self, *args, **kwargs):
  >             raise error.Abort(b'emulating unexpected abort')
  >     repo.__class__ = commitfailure
  > EOF
  $ cat >> .hg/hgrc <<EOF
  > [extensions]
  > # this failure occurs before editor invocation
  > commitfailure = $TESTTMP/commitfailure.py
  > EOF

  $ cat > $TESTTMP/editor.sh << EOF
  > echo "==== before editing"
  > cat \$1
  > echo "===="
  > echo "test saving last-message.txt" >> \$1
  > EOF

(test that editor is not invoked before transaction starting)

  $ rm -f .hg/last-message.txt
  $ HGEDITOR="sh $TESTTMP/editor.sh" hg qnew -e patch
  abort: emulating unexpected abort
  [255]
  $ test -f .hg/last-message.txt
  [1]

(test that editor is invoked and commit message is saved into
"last-message.txt")

  $ cat >> .hg/hgrc <<EOF
  > [extensions]
  > commitfailure = !
  > [hooks]
  > # this failure occurs after editor invocation
  > pretxncommit.unexpectedabort = false
  > EOF

  $ rm -f .hg/last-message.txt
  $ hg status
  $ HGEDITOR="sh $TESTTMP/editor.sh" hg qnew -e patch
  ==== before editing
  
  
  HG: Enter commit message.  Lines beginning with 'HG:' are removed.
  HG: Leave message empty to use default message.
  HG: --
  HG: user: test
  HG: branch 'default'
  HG: no files changed
  ====
  transaction abort!
  rollback completed
  note: commit message saved in .hg/last-message.txt
  note: use 'hg commit --logfile .hg/last-message.txt --edit' to reuse it
  abort: pretxncommit.unexpectedabort hook exited with status 1
  [40]
  $ cat .hg/last-message.txt
  
  
  test saving last-message.txt

  $ cat >> .hg/hgrc <<EOF
  > [hooks]
  > pretxncommit.unexpectedabort =
  > EOF