view tests/test-obshistory.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

This test file test the various messages when accessing obsolete
revisions.

Global setup
============

  $ . $TESTDIR/testlib/obsmarker-common.sh
  $ cat >> $HGRCPATH <<EOF
  > [ui]
  > interactive = true
  > [phases]
  > publish=False
  > [experimental]
  > evolution.createmarkers = yes
  > evolution.effect-flags = yes
  > EOF

Test output on amended commit
=============================

Test setup
----------

  $ hg init $TESTTMP/local-amend
  $ cd $TESTTMP/local-amend
  $ mkcommit ROOT
  $ mkcommit A0
  $ echo 42 >> A0
  $ hg commit --amend -m "A1
  > 
  > Better commit message"
  $ hg log --hidden -G
  @  changeset:   2:4ae3a4151de9
  |  tag:         tip
  |  parent:      0:ea207398892e
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     A1
  |
  | x  changeset:   1:471f378eab4c
  |/   user:        test
  |    date:        Thu Jan 01 00:00:00 1970 +0000
  |    obsolete:    rewritten using amend as 2:4ae3a4151de9
  |    summary:     A0
  |
  o  changeset:   0:ea207398892e
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     ROOT
  
Actual test
-----------
  $ hg update 471f378eab4c
  abort: hidden revision '471f378eab4c' was rewritten as: 4ae3a4151de9
  (use --hidden to access hidden revisions)
  [255]
  $ hg update --hidden "desc(A0)"
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  updated to hidden changeset 471f378eab4c
  (hidden revision '471f378eab4c' was rewritten as: 4ae3a4151de9)

Test output with pruned commit
==============================

Test setup
----------

  $ hg init $TESTTMP/local-prune
  $ cd $TESTTMP/local-prune
  $ mkcommit ROOT
  $ mkcommit A0 # 0
  $ mkcommit B0 # 1
  $ hg log --hidden -G
  @  changeset:   2:0dec01379d3b
  |  tag:         tip
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     B0
  |
  o  changeset:   1:471f378eab4c
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     A0
  |
  o  changeset:   0:ea207398892e
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     ROOT
  
  $ hg debugobsolete --record-parents `getid 'desc(B0)'`
  1 new obsolescence markers
  obsoleted 1 changesets

  $ hg log --hidden -G
  @  changeset:   2:0dec01379d3b
  |  tag:         tip
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  obsolete:    pruned
  |  summary:     B0
  |
  o  changeset:   1:471f378eab4c
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     A0
  |
  o  changeset:   0:ea207398892e
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     ROOT
  

Actual test
-----------
  $ hg up 1
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ hg up 0dec01379d3b
  abort: hidden revision '0dec01379d3b' is pruned
  (use --hidden to access hidden revisions)
  [255]
  $ hg up --hidden -r 'desc(B0)'
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  updated to hidden changeset 0dec01379d3b
  (hidden revision '0dec01379d3b' is pruned)

Test output with splitted commit
================================

Test setup
----------

  $ hg init $TESTTMP/local-split
  $ cd $TESTTMP/local-split
  $ mkcommit ROOT
  $ echo 42 >> a
  $ echo 43 >> b
  $ hg commit -A -m "A0"
  adding a
  adding b
  $ hg log --hidden -G
  @  changeset:   1:471597cad322
  |  tag:         tip
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     A0
  |
  o  changeset:   0:ea207398892e
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     ROOT
  
# Simulate a split
  $ hg up 0
  0 files updated, 0 files merged, 2 files removed, 0 files unresolved

  $ echo 42 >> a
  $ hg commit -A -m "A0"
  adding a
  created new head

  $ echo 43 >> b
  $ hg commit -A -m "A0"
  adding b

  $ hg debugobsolete `getid '1'` `getid '2'` `getid '3'`
  1 new obsolescence markers
  obsoleted 1 changesets

  $ hg log --hidden -G
  @  changeset:   3:f257fde29c7a
  |  tag:         tip
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     A0
  |
  o  changeset:   2:337fec4d2edc
  |  parent:      0:ea207398892e
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     A0
  |
  | x  changeset:   1:471597cad322
  |/   user:        test
  |    date:        Thu Jan 01 00:00:00 1970 +0000
  |    obsolete:    split as 2:337fec4d2edc, 3:f257fde29c7a
  |    summary:     A0
  |
  o  changeset:   0:ea207398892e
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     ROOT
  
Actual test
-----------
  $ hg update 471597cad322
  abort: hidden revision '471597cad322' was split as: 337fec4d2edc, f257fde29c7a
  (use --hidden to access hidden revisions)
  [255]
  $ hg update --hidden 'min(desc(A0))'
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  updated to hidden changeset 471597cad322
  (hidden revision '471597cad322' was split as: 337fec4d2edc, f257fde29c7a)

Test output with lots of splitted commit
========================================

Test setup
----------

  $ hg init $TESTTMP/local-lots-split
  $ cd $TESTTMP/local-lots-split
  $ mkcommit ROOT
  $ echo 42 >> a
  $ echo 43 >> b
  $ echo 44 >> c
  $ echo 45 >> d
  $ hg commit -A -m "A0"
  adding a
  adding b
  adding c
  adding d
  $ hg log --hidden -G
  @  changeset:   1:de7290d8b885
  |  tag:         tip
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     A0
  |
  o  changeset:   0:ea207398892e
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     ROOT
  
# Simulate a split
  $ hg up 0
  0 files updated, 0 files merged, 4 files removed, 0 files unresolved

  $ echo 42 >> a
  $ hg commit -A -m "A0"
  adding a
  created new head

  $ echo 43 >> b
  $ hg commit -A -m "A0"
  adding b

  $ echo 44 >> c
  $ hg commit -A -m "A0"
  adding c

  $ echo 45 >> d
  $ hg commit -A -m "A0"
  adding d

  $ hg debugobsolete `getid '1'` `getid '2'` `getid '3'` `getid '4'` `getid '5'`
  1 new obsolescence markers
  obsoleted 1 changesets

  $ hg log --hidden -G
  @  changeset:   5:c7f044602e9b
  |  tag:         tip
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     A0
  |
  o  changeset:   4:1ae8bc733a14
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     A0
  |
  o  changeset:   3:f257fde29c7a
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     A0
  |
  o  changeset:   2:337fec4d2edc
  |  parent:      0:ea207398892e
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     A0
  |
  | x  changeset:   1:de7290d8b885
  |/   user:        test
  |    date:        Thu Jan 01 00:00:00 1970 +0000
  |    obsolete:    split as 2:337fec4d2edc, 3:f257fde29c7a, 4:1ae8bc733a14, 5:c7f044602e9b
  |    summary:     A0
  |
  o  changeset:   0:ea207398892e
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     ROOT
  
Actual test
-----------
  $ hg update de7290d8b885
  abort: hidden revision 'de7290d8b885' was split as: 337fec4d2edc, f257fde29c7a and 2 more
  (use --hidden to access hidden revisions)
  [255]
  $ hg update --hidden 'min(desc(A0))'
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  updated to hidden changeset de7290d8b885
  (hidden revision 'de7290d8b885' was split as: 337fec4d2edc, f257fde29c7a and 2 more)

Test output with folded commit
==============================

Test setup
----------

  $ hg init $TESTTMP/local-fold
  $ cd $TESTTMP/local-fold
  $ mkcommit ROOT
  $ mkcommit A0
  $ mkcommit B0
  $ hg log --hidden -G
  @  changeset:   2:0dec01379d3b
  |  tag:         tip
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     B0
  |
  o  changeset:   1:471f378eab4c
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     A0
  |
  o  changeset:   0:ea207398892e
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     ROOT
  
# Simulate a fold
  $ hg up 0
  0 files updated, 0 files merged, 2 files removed, 0 files unresolved
  $ echo "A0" > A0
  $ echo "B0" > B0
  $ hg add A0 B0
  $ hg commit -m "C0"
  created new head

  $ hg debugobsolete `getid 'desc(A0)'` `getid 'desc(C0)'`
  1 new obsolescence markers
  obsoleted 1 changesets
  1 new orphan changesets
  $ hg debugobsolete `getid 'desc(B0)'` `getid 'desc(C0)'`
  1 new obsolescence markers
  obsoleted 1 changesets

  $ hg log --hidden -G
  @  changeset:   3:eb5a0daa2192
  |  tag:         tip
  |  parent:      0:ea207398892e
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     C0
  |
  | x  changeset:   2:0dec01379d3b
  | |  user:        test
  | |  date:        Thu Jan 01 00:00:00 1970 +0000
  | |  obsolete:    rewritten as 3:eb5a0daa2192
  | |  summary:     B0
  | |
  | x  changeset:   1:471f378eab4c
  |/   user:        test
  |    date:        Thu Jan 01 00:00:00 1970 +0000
  |    obsolete:    rewritten as 3:eb5a0daa2192
  |    summary:     A0
  |
  o  changeset:   0:ea207398892e
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     ROOT
  
 Actual test
 -----------
  $ hg update 471f378eab4c
  abort: hidden revision '471f378eab4c' was rewritten as: eb5a0daa2192
  (use --hidden to access hidden revisions)
  [255]
  $ hg update --hidden 'desc(A0)'
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  updated to hidden changeset 471f378eab4c
  (hidden revision '471f378eab4c' was rewritten as: eb5a0daa2192)
  $ hg update 0dec01379d3b
  abort: hidden revision '0dec01379d3b' was rewritten as: eb5a0daa2192
  (use --hidden to access hidden revisions)
  [255]
  $ hg update --hidden 'desc(B0)'
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  updated to hidden changeset 0dec01379d3b
  (hidden revision '0dec01379d3b' was rewritten as: eb5a0daa2192)

Test output with divergence
===========================

Test setup
----------

  $ hg init $TESTTMP/local-divergence
  $ cd $TESTTMP/local-divergence
  $ mkcommit ROOT
  $ mkcommit A0
  $ hg commit --amend -m "A1"
  $ hg log --hidden -G
  @  changeset:   2:fdf9bde5129a
  |  tag:         tip
  |  parent:      0:ea207398892e
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     A1
  |
  | x  changeset:   1:471f378eab4c
  |/   user:        test
  |    date:        Thu Jan 01 00:00:00 1970 +0000
  |    obsolete:    rewritten using amend as 2:fdf9bde5129a
  |    summary:     A0
  |
  o  changeset:   0:ea207398892e
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     ROOT
  
  $ hg update --hidden 'desc(A0)'
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  updated to hidden changeset 471f378eab4c
  (hidden revision '471f378eab4c' was rewritten as: fdf9bde5129a)
  $ hg commit --amend -m "A2"
  2 new content-divergent changesets
  $ hg log --hidden -G
  @  changeset:   3:65b757b745b9
  |  tag:         tip
  |  parent:      0:ea207398892e
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  instability: content-divergent
  |  summary:     A2
  |
  | *  changeset:   2:fdf9bde5129a
  |/   parent:      0:ea207398892e
  |    user:        test
  |    date:        Thu Jan 01 00:00:00 1970 +0000
  |    instability: content-divergent
  |    summary:     A1
  |
  | x  changeset:   1:471f378eab4c
  |/   user:        test
  |    date:        Thu Jan 01 00:00:00 1970 +0000
  |    obsolete:    rewritten using amend as 2:fdf9bde5129a
  |    obsolete:    rewritten using amend as 3:65b757b745b9
  |    summary:     A0
  |
  o  changeset:   0:ea207398892e
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     ROOT
  
Actual test
-----------
  $ hg update 471f378eab4c
  abort: hidden revision '471f378eab4c' has diverged
  (use --hidden to access hidden revisions)
  [255]
  $ hg update --hidden 'desc(A0)'
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  updated to hidden changeset 471f378eab4c
  (hidden revision '471f378eab4c' has diverged)

Test output with amended + folded commit
========================================

Test setup
----------

  $ hg init $TESTTMP/local-amend-fold
  $ cd $TESTTMP/local-amend-fold
  $ mkcommit ROOT
  $ mkcommit A0
  $ mkcommit B0
  $ hg commit --amend -m "B1"
  $ hg log --hidden -G
  @  changeset:   3:b7ea6d14e664
  |  tag:         tip
  |  parent:      1:471f378eab4c
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     B1
  |
  | x  changeset:   2:0dec01379d3b
  |/   user:        test
  |    date:        Thu Jan 01 00:00:00 1970 +0000
  |    obsolete:    rewritten using amend as 3:b7ea6d14e664
  |    summary:     B0
  |
  o  changeset:   1:471f378eab4c
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     A0
  |
  o  changeset:   0:ea207398892e
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     ROOT
  

# Simulate a fold
  $ hg up 0
  0 files updated, 0 files merged, 2 files removed, 0 files unresolved
  $ echo "A0" > A0
  $ echo "B0" > B0
  $ hg add A0 B0
  $ hg commit -m "C0"
  created new head

  $ hg debugobsolete `getid 'desc(A0)'` `getid 'desc(C0)'`
  1 new obsolescence markers
  obsoleted 1 changesets
  1 new orphan changesets
  $ hg debugobsolete `getid 'desc(B1)'` `getid 'desc(C0)'`
  1 new obsolescence markers
  obsoleted 1 changesets

  $ hg log --hidden -G
  @  changeset:   4:eb5a0daa2192
  |  tag:         tip
  |  parent:      0:ea207398892e
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     C0
  |
  | x  changeset:   3:b7ea6d14e664
  | |  parent:      1:471f378eab4c
  | |  user:        test
  | |  date:        Thu Jan 01 00:00:00 1970 +0000
  | |  obsolete:    rewritten as 4:eb5a0daa2192
  | |  summary:     B1
  | |
  | | x  changeset:   2:0dec01379d3b
  | |/   user:        test
  | |    date:        Thu Jan 01 00:00:00 1970 +0000
  | |    obsolete:    rewritten using amend as 3:b7ea6d14e664
  | |    summary:     B0
  | |
  | x  changeset:   1:471f378eab4c
  |/   user:        test
  |    date:        Thu Jan 01 00:00:00 1970 +0000
  |    obsolete:    rewritten as 4:eb5a0daa2192
  |    summary:     A0
  |
  o  changeset:   0:ea207398892e
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     ROOT
  
 Actual test
 -----------
  $ hg update 471f378eab4c
  abort: hidden revision '471f378eab4c' was rewritten as: eb5a0daa2192
  (use --hidden to access hidden revisions)
  [255]
  $ hg update --hidden 'desc(A0)'
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  updated to hidden changeset 471f378eab4c
  (hidden revision '471f378eab4c' was rewritten as: eb5a0daa2192)
  $ hg update --hidden 0dec01379d3b
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  updated to hidden changeset 0dec01379d3b
  (hidden revision '0dec01379d3b' was rewritten as: eb5a0daa2192)
  $ hg update 0dec01379d3b
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg update --hidden 'desc(B0)'
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved