view tests/test-githelp.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

  $ cat >> $HGRCPATH << EOF
  > [extensions]
  > githelp =
  > EOF

  $ hg init repo
  $ cd repo
  $ echo foo > test_file
  $ mkdir dir
  $ echo foo > dir/file
  $ echo foo > removed_file
  $ echo foo > deleted_file
  $ hg add -q .
  $ hg commit -m 'bar'
  $ hg bookmark both
  $ touch both
  $ touch untracked_file
  $ hg remove removed_file
  $ rm deleted_file

githelp on a single command should succeed
  $ hg githelp -- commit
  hg commit
  $ hg githelp -- git commit
  hg commit

githelp should fail nicely if we don't give it arguments
  $ hg githelp
  abort: missing git command - usage: hg githelp -- <git command>
  [255]
  $ hg githelp -- git
  abort: missing git command - usage: hg githelp -- <git command>
  [255]

githelp on a command with options should succeed
  $ hg githelp -- commit -pm "abc"
  hg commit --interactive -m 'abc'

githelp on a command with standalone unrecognized option should succeed with warning
  $ hg githelp -- commit -p -v
  ignoring unknown option -v
  hg commit --interactive

githelp on a command with unrecognized option packed with other options should fail with error
  $ hg githelp -- commit -pv
  abort: unknown option 'v' packed with other options
  (please try passing the option as its own flag: -v)
  [255]

githelp for git rebase --skip
  $ hg githelp -- git rebase --skip
  hg revert --all -r .
  hg rebase --continue

githelp for git commit --amend (hg commit --amend pulls up an editor)
  $ hg githelp -- commit --amend
  hg commit --amend

githelp for git commit --amend --no-edit (hg amend does not pull up an editor)
  $ hg githelp -- commit --amend --no-edit
  hg amend

githelp for git checkout -- . (checking out a directory)
  $ hg githelp -- checkout -- .
  note: use --no-backup to avoid creating .orig files
  
  hg revert .

githelp for git checkout "HEAD^" (should still work to pass a rev)
  $ hg githelp -- checkout "HEAD^"
  hg update .^

githelp checkout: args after -- should be treated as paths no matter what
  $ hg githelp -- checkout -- HEAD
  note: use --no-backup to avoid creating .orig files
  
  hg revert HEAD

githelp for git checkout with rev and path
  $ hg githelp -- checkout "HEAD^" -- file.txt
  note: use --no-backup to avoid creating .orig files
  
  hg revert -r .^ file.txt

githelp for git with rev and path, without separator
  $ hg githelp -- checkout "HEAD^" file.txt
  note: use --no-backup to avoid creating .orig files
  
  hg revert -r .^ file.txt

githelp for checkout with a file as first argument
  $ hg githelp -- checkout test_file
  note: use --no-backup to avoid creating .orig files
  
  hg revert test_file

githelp for checkout with a removed file as first argument
  $ hg githelp -- checkout removed_file
  note: use --no-backup to avoid creating .orig files
  
  hg revert removed_file

githelp for checkout with a deleted file as first argument
  $ hg githelp -- checkout deleted_file
  note: use --no-backup to avoid creating .orig files
  
  hg revert deleted_file

githelp for checkout with a untracked file as first argument
  $ hg githelp -- checkout untracked_file
  note: use --no-backup to avoid creating .orig files
  
  hg revert untracked_file

githelp for checkout with a directory as first argument
  $ hg githelp -- checkout dir
  note: use --no-backup to avoid creating .orig files
  
  hg revert dir

githelp for checkout when not in repo root
  $ cd dir
  $ hg githelp -- checkout file
  note: use --no-backup to avoid creating .orig files
  
  hg revert file

  $ cd ..

githelp for checkout with an argument that is both a file and a revision
  $ hg githelp -- checkout both
  hg update both

githelp for checkout with the -p option
  $ hg githelp -- git checkout -p xyz
  hg revert -i -r xyz

  $ hg githelp -- git checkout -p xyz -- abc
  note: use --no-backup to avoid creating .orig files
  
  hg revert -i -r xyz abc

githelp for checkout with the -f option and a rev
  $ hg githelp -- git checkout -f xyz
  hg update -C xyz
  $ hg githelp -- git checkout --force xyz
  hg update -C xyz

githelp for checkout with the -f option without an arg
  $ hg githelp -- git checkout -f
  hg revert --all
  $ hg githelp -- git checkout --force
  hg revert --all

githelp for grep with pattern and path
  $ hg githelp -- grep shrubbery flib/intern/
  hg grep shrubbery flib/intern/

githelp for reset, checking ~ in git becomes ~1 in mercurial
  $ hg githelp -- reset HEAD~
  hg update .~1
  $ hg githelp -- reset "HEAD^"
  hg update .^
  $ hg githelp -- reset HEAD~3
  hg update .~3

  $ hg githelp -- reset --mixed HEAD
  note: --mixed has no meaning since Mercurial has no staging area
  
  hg update .
  $ hg githelp -- reset --soft HEAD
  note: --soft has no meaning since Mercurial has no staging area
  
  hg update .
  $ hg githelp -- reset --hard HEAD
  hg update --clean .

githelp for git show --name-status
  $ hg githelp -- git show --name-status
  hg log --style status -r .

githelp for git show --pretty=format: --name-status
  $ hg githelp -- git show --pretty=format: --name-status
  hg status --change .

githelp for show with no arguments
  $ hg githelp -- show
  hg export

githelp for show with a path
  $ hg githelp -- show test_file
  hg cat test_file

githelp for show with not a path:
  $ hg githelp -- show rev
  hg export rev

githelp for show with many arguments
  $ hg githelp -- show argone argtwo
  hg export argone argtwo
  $ hg githelp -- show test_file argone argtwo
  hg cat test_file argone argtwo

githelp for show with --unified options
  $ hg githelp -- show --unified=10
  hg export --config diff.unified=10
  $ hg githelp -- show -U100
  hg export --config diff.unified=100

githelp for show with a path and --unified
  $ hg githelp -- show -U20 test_file
  hg cat test_file --config diff.unified=20

githelp for stash drop without name
  $ hg githelp -- git stash drop
  hg shelve -d <shelve name>

githelp for stash drop with name
  $ hg githelp -- git stash drop xyz
  hg shelve -d xyz

githelp for stash list with patch
  $ hg githelp -- git stash list -p
  hg shelve -l -p

githelp for stash show
  $ hg githelp -- git stash show
  hg shelve --stat

githelp for stash show with patch and name
  $ hg githelp -- git stash show -p mystash
  hg shelve -p mystash

githelp for stash clear
  $ hg githelp -- git stash clear
  hg shelve --cleanup

githelp for whatchanged should show deprecated message
  $ hg githelp -- whatchanged -p
  this command has been deprecated in the git project, thus isn't supported by this tool
  

githelp for git branch -m renaming
  $ hg githelp -- git branch -m old new
  hg bookmark -m old new

When the old name is omitted, git branch -m new renames the current branch.
  $ hg githelp -- git branch -m new
  hg bookmark -m `hg log -T"{activebookmark}" -r .` new

Branch deletion in git strips commits
  $ hg githelp -- git branch -d
  hg strip -B
  $ hg githelp -- git branch -d feature
  hg strip -B feature -B
  $ hg githelp -- git branch --delete experiment1 experiment2
  hg strip -B experiment1 -B experiment2 -B

githelp for reuse message using the shorthand
  $ hg githelp -- git commit -C deadbeef
  hg commit -M deadbeef

githelp for reuse message using the the long version
  $ hg githelp -- git commit --reuse-message deadbeef
  hg commit -M deadbeef

githelp for reuse message using HEAD
  $ hg githelp -- git commit --reuse-message HEAD~
  hg commit -M .~1

githelp for apply with no options
  $ hg githelp -- apply
  hg import --no-commit

githelp for apply with directory strip custom
  $ hg githelp -- apply -p 5
  hg import --no-commit -p 5

githelp for apply with prefix directory
  $ hg githelp -- apply --directory=modules
  hg import --no-commit --prefix modules

git merge-base
  $ hg githelp -- git merge-base --is-ancestor
  ignoring unknown option --is-ancestor
  note: ancestors() is part of the revset language
  (learn more about revsets with 'hg help revsets')
  
  hg log -T '{node}\n' -r 'ancestor(A,B)'

githelp for git blame
  $ hg githelp -- git blame
  hg annotate -udl

githelp for add

  $ hg githelp -- git add
  hg add

  $ hg githelp -- git add -p
  note: Mercurial will commit when complete, as there is no staging area in Mercurial
  
  hg commit --interactive

  $ hg githelp -- git add --all
  note: use hg addremove to remove files that have been deleted
  
  hg add

githelp for reflog

  $ hg githelp -- git reflog
  hg journal
  
  note: in hg commits can be deleted from repo but we always have backups

  $ hg githelp -- git reflog --all
  hg journal --all
  
  note: in hg commits can be deleted from repo but we always have backups

  $ hg githelp -- git log -Gnarf
  hg grep --diff narf
  $ hg githelp -- git log -S narf
  hg grep --diff narf
  $ hg githelp -- git log --pickaxe-regex narf
  hg grep --diff narf