view tests/test-histedit-obsolete.t @ 40326:fed697fa1734

sqlitestore: file storage backend using SQLite

This commit provides an extension which uses SQLite to store file
data (as opposed to revlogs).

As the inline documentation describes, there are still several
aspects to the extension that are incomplete. But it's a start.
The extension does support basic clone, checkout, and commit
workflows, which makes it suitable for simple use cases.

One notable missing feature is support for "bundlerepos." This is
probably responsible for the most test failures when the extension
is activated as part of the test suite.

All revision data is stored in SQLite. Data is stored as zstd
compressed chunks (default if zstd is available), zlib compressed
chunks (default if zstd is not available), or raw chunks (if
configured or if a compressed delta is not smaller than the raw
delta). This makes things very similar to revlogs.

Unlike revlogs, the extension doesn't yet enforce a limit on delta
chain length. This is an obvious limitation and should be addressed.
This is somewhat mitigated by the use of zstd, which is much faster
than zlib to decompress.

There is a dedicated table for storing deltas. Deltas are stored
by the SHA-1 hash of their uncompressed content. The "fileindex" table
has columns that reference the delta for each revision and the base
delta that delta should be applied against. A recursive SQL query
is used to resolve the delta chain along with the delta data.

By storing deltas by hash, we are able to de-duplicate delta storage!
With revlogs, the same deltas in different revlogs would result in
duplicate storage of that delta. In this scheme, inserting the
duplicate delta is a no-op and delta chains simply reference the
existing delta.

When initially implementing this extension, I did not have
content-indexed deltas and deltas could be duplicated across files
(just like revlogs). When I implemented content-indexed deltas, the
size of the SQLite database for a full clone of mozilla-unified
dropped:

before: 2,554,261,504 bytes
after:  2,488,754,176 bytes

Surprisingly, this is still larger than the bytes size of revlog
files:

revlog files: 2,104,861,230 bytes
du -b:        2,254,381,614

I would have expected storage to be smaller since we're not limiting
delta chain length and since we're using zstd instead of zlib. I
suspect the SQLite indexes and per-column overhead account for the
bulk of the differences. (Keep in mind that revlog uses a 64-byte
packed struct for revision index data and deltas are stored without
padding. Aside from the 12 unused bytes in the 32 byte node field,
revlogs are pretty efficient.) Another source of overhead is file
name storage. With revlogs, file names are stored in the filesystem.
But with SQLite, we need to store file names in the database. This is
roughly equivalent to the size of the fncache file, which for the
mozilla-unified repository is ~34MB.

Since the SQLite database isn't append-only and since delta chains
can reference any delta, this opens some interesting possibilities.
For example, we could store deltas in reverse, such that fulltexts
are stored for newer revisions and deltas are applied to reconstruct
older revisions. This is likely a more optimal storage strategy for
version control, as new data tends to be more frequently accessed
than old data. We would obviously need wire protocol support for
transferring revision data from newest to oldest. And we would
probably need some kind of mechanism for "re-encoding" stores. But
it should be doable.

This extension is very much experimental quality. There are a handful
of features that don't work. It probably isn't suitable for day-to-day
use. But it could be used in limited cases (e.g. read-only checkouts
like in CI). And it is also a good proving ground for alternate
storage backends. As we continue to define interfaces for all things
storage, it will be useful to have a viable alternate storage backend
to see how things shake out in practice.

test-storage.py passes on Python 2 and introduces no new test failures on
Python 3. Having the storage-level unit tests has proved to be insanely
useful when developing this extension. Those tests caught numerous bugs
during development and I'm convinced this style of testing is the way
forward for ensuring alternate storage backends work as intended. Of
course, test coverage isn't close to what it needs to be. But it is
a start. And what coverage we have gives me confidence that basic store
functionality is implemented properly.

Differential Revision: https://phab.mercurial-scm.org/D4928

  $ . "$TESTDIR/histedit-helpers.sh"

Enable obsolete

  $ cat >> $HGRCPATH << EOF
  > [ui]
  > logtemplate= {rev}:{node|short} {desc|firstline}
  > [phases]
  > publish=False
  > [experimental]
  > evolution.createmarkers=True
  > evolution.allowunstable=True
  > [extensions]
  > histedit=
  > rebase=
  > EOF

Test that histedit learns about obsolescence not stored in histedit state
  $ hg init boo
  $ cd boo
  $ echo a > a
  $ hg ci -Am a
  adding a
  $ echo a > b
  $ echo a > c
  $ echo a > c
  $ hg ci -Am b
  adding b
  adding c
  $ echo a > d
  $ hg ci -Am c
  adding d
  $ echo "pick `hg log -r 0 -T '{node|short}'`" > plan
  $ echo "pick `hg log -r 2 -T '{node|short}'`" >> plan
  $ echo "edit `hg log -r 1 -T '{node|short}'`" >> plan
  $ hg histedit -r 'all()' --commands plan
  Editing (1b2d564fad96), you may commit or record as needed now.
  (hg histedit --continue to resume)
  [1]
  $ hg st
  A b
  A c
  ? plan
  $ hg commit --amend b
  $ hg histedit --continue
  $ hg log -G
  @  5:46abc7c4d873 b
  |
  o  4:49d44ab2be1b c
  |
  o  0:cb9a9f314b8b a
  
  $ hg debugobsolete
  e72d22b19f8ecf4150ab4f91d0973fd9955d3ddf 49d44ab2be1b67a79127568a67c9c99430633b48 0 (Thu Jan 01 00:00:00 1970 +0000) {'ef1': '8', 'operation': 'amend', 'user': 'test'}
  1b2d564fad96311b45362f17c2aa855150efb35f 46abc7c4d8738e8563e577f7889e1b6db3da4199 0 (Thu Jan 01 00:00:00 1970 +0000) {'ef1': '12', 'operation': 'histedit', 'user': 'test'}
  114f4176969ef342759a8a57e6bccefc4234829b 49d44ab2be1b67a79127568a67c9c99430633b48 0 (Thu Jan 01 00:00:00 1970 +0000) {'ef1': '12', 'operation': 'histedit', 'user': 'test'}

With some node gone missing during the edit.

  $ echo "pick `hg log -r 0 -T '{node|short}'`" > plan
  $ echo "pick `hg log -r 5 -T '{node|short}'`" >> plan
  $ echo "edit `hg log -r 4 -T '{node|short}'`" >> plan
  $ hg histedit -r 'all()' --commands plan
  Editing (49d44ab2be1b), you may commit or record as needed now.
  (hg histedit --continue to resume)
  [1]
  $ hg st
  A b
  A d
  ? plan
  $ hg commit --amend -X . -m XXXXXX
  $ hg commit --amend -X . -m b2
  $ hg --hidden --config extensions.strip= strip 'desc(XXXXXX)' --no-backup
  $ hg histedit --continue
  $ hg log -G
  @  8:273c1f3b8626 c
  |
  o  7:aba7da937030 b2
  |
  o  0:cb9a9f314b8b a
  
  $ hg debugobsolete
  e72d22b19f8ecf4150ab4f91d0973fd9955d3ddf 49d44ab2be1b67a79127568a67c9c99430633b48 0 (Thu Jan 01 00:00:00 1970 +0000) {'ef1': '8', 'operation': 'amend', 'user': 'test'}
  1b2d564fad96311b45362f17c2aa855150efb35f 46abc7c4d8738e8563e577f7889e1b6db3da4199 0 (Thu Jan 01 00:00:00 1970 +0000) {'ef1': '12', 'operation': 'histedit', 'user': 'test'}
  114f4176969ef342759a8a57e6bccefc4234829b 49d44ab2be1b67a79127568a67c9c99430633b48 0 (Thu Jan 01 00:00:00 1970 +0000) {'ef1': '12', 'operation': 'histedit', 'user': 'test'}
  76f72745eac0643d16530e56e2f86e36e40631f1 2ca853e48edbd6453a0674dc0fe28a0974c51b9c 0 (Thu Jan 01 00:00:00 1970 +0000) {'ef1': '1', 'operation': 'amend', 'user': 'test'}
  2ca853e48edbd6453a0674dc0fe28a0974c51b9c aba7da93703075eec9fb1dbaf143ff2bc1c49d46 0 (Thu Jan 01 00:00:00 1970 +0000) {'ef1': '1', 'operation': 'amend', 'user': 'test'}
  49d44ab2be1b67a79127568a67c9c99430633b48 273c1f3b86267ed3ec684bb13af1fa4d6ba56e02 0 (Thu Jan 01 00:00:00 1970 +0000) {'ef1': '4', 'operation': 'histedit', 'user': 'test'}
  46abc7c4d8738e8563e577f7889e1b6db3da4199 aba7da93703075eec9fb1dbaf143ff2bc1c49d46 0 (Thu Jan 01 00:00:00 1970 +0000) {'ef1': '5', 'operation': 'histedit', 'user': 'test'}
  $ cd ..

Base setup for the rest of the testing
======================================

  $ hg init base
  $ cd base

  $ for x in a b c d e f ; do
  >     echo $x > $x
  >     hg add $x
  >     hg ci -m $x
  > done

  $ hg log --graph
  @  5:652413bf663e f
  |
  o  4:e860deea161a e
  |
  o  3:055a42cdd887 d
  |
  o  2:177f92b77385 c
  |
  o  1:d2ae7f538514 b
  |
  o  0:cb9a9f314b8b a
  

  $ HGEDITOR=cat hg histedit 1
  pick d2ae7f538514 1 b
  pick 177f92b77385 2 c
  pick 055a42cdd887 3 d
  pick e860deea161a 4 e
  pick 652413bf663e 5 f
  
  # Edit history between d2ae7f538514 and 652413bf663e
  #
  # Commits are listed from least to most recent
  #
  # You can reorder changesets by reordering the lines
  #
  # Commands:
  #
  #  e, edit = use commit, but stop for amending
  #  m, mess = edit commit message without changing commit content
  #  p, pick = use commit
  #  b, base = checkout changeset and apply further changesets from there
  #  d, drop = remove commit from history
  #  f, fold = use commit, but combine it with the one above
  #  r, roll = like fold, but discard this commit's description and date
  #
  $ hg histedit 1 --commands - --verbose <<EOF | grep histedit
  > pick 177f92b77385 2 c
  > drop d2ae7f538514 1 b
  > pick 055a42cdd887 3 d
  > fold e860deea161a 4 e
  > pick 652413bf663e 5 f
  > EOF
  [1]
  $ hg log --graph --hidden
  @  10:cacdfd884a93 f
  |
  o  9:59d9f330561f d
  |
  | x  8:b558abc46d09 fold-temp-revision e860deea161a
  | |
  | x  7:96e494a2d553 d
  |/
  o  6:b346ab9a313d c
  |
  | x  5:652413bf663e f
  | |
  | x  4:e860deea161a e
  | |
  | x  3:055a42cdd887 d
  | |
  | x  2:177f92b77385 c
  | |
  | x  1:d2ae7f538514 b
  |/
  o  0:cb9a9f314b8b a
  
  $ hg debugobsolete
  d2ae7f538514cd87c17547b0de4cea71fe1af9fb 0 {cb9a9f314b8b07ba71012fcdbc544b5a4d82ff5b} (Thu Jan 01 00:00:00 1970 +0000) {'ef1': '0', 'operation': 'histedit', 'user': 'test'}
  177f92b773850b59254aa5e923436f921b55483b b346ab9a313db8537ecf96fca3ca3ca984ef3bd7 0 (Thu Jan 01 00:00:00 1970 +0000) {'ef1': '4', 'operation': 'histedit', 'user': 'test'}
  055a42cdd88768532f9cf79daa407fc8d138de9b 59d9f330561fd6c88b1a6b32f0e45034d88db784 0 (Thu Jan 01 00:00:00 1970 +0000) {'ef1': '13', 'operation': 'histedit', 'user': 'test'}
  e860deea161a2f77de56603b340ebbb4536308ae 59d9f330561fd6c88b1a6b32f0e45034d88db784 0 (Thu Jan 01 00:00:00 1970 +0000) {'ef1': '13', 'operation': 'histedit', 'user': 'test'}
  652413bf663ef2a641cab26574e46d5f5a64a55a cacdfd884a9321ec4e1de275ef3949fa953a1f83 0 (Thu Jan 01 00:00:00 1970 +0000) {'ef1': '4', 'operation': 'histedit', 'user': 'test'}
  96e494a2d553dd05902ba1cee1d94d4cb7b8faed 0 {b346ab9a313db8537ecf96fca3ca3ca984ef3bd7} (Thu Jan 01 00:00:00 1970 +0000) {'ef1': '0', 'operation': 'histedit', 'user': 'test'}
  b558abc46d09c30f57ac31e85a8a3d64d2e906e4 0 {96e494a2d553dd05902ba1cee1d94d4cb7b8faed} (Thu Jan 01 00:00:00 1970 +0000) {'ef1': '0', 'operation': 'histedit', 'user': 'test'}


Ensure hidden revision does not prevent histedit
-------------------------------------------------

create an hidden revision

  $ hg histedit 6 --commands - << EOF
  > pick b346ab9a313d 6 c
  > drop 59d9f330561f 7 d
  > pick cacdfd884a93 8 f
  > EOF
  $ hg log --graph
  @  11:c13eb81022ca f
  |
  o  6:b346ab9a313d c
  |
  o  0:cb9a9f314b8b a
  
check hidden revision are ignored (6 have hidden children 7 and 8)

  $ hg histedit 6 --commands - << EOF
  > pick b346ab9a313d 6 c
  > pick c13eb81022ca 8 f
  > EOF



Test that rewriting leaving instability behind is allowed
---------------------------------------------------------------------

  $ hg up '.^'
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ hg log -r 'children(.)'
  11:c13eb81022ca f (no-eol)
  $ hg histedit -r '.' --commands - <<EOF
  > edit b346ab9a313d 6 c
  > EOF
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  adding c
  Editing (b346ab9a313d), you may commit or record as needed now.
  (hg histedit --continue to resume)
  [1]
  $ echo c >> c
  $ hg histedit --continue
  1 new orphan changesets

  $ hg log -r 'orphan()'
  11:c13eb81022ca f (no-eol)

stabilise

  $ hg rebase  -r 'orphan()' -d .
  rebasing 11:c13eb81022ca "f"
  $ hg up tip -q

Test dropping of changeset on the top of the stack
-------------------------------------------------------

Nothing is rewritten below, the working directory parent must be change for the
dropped changeset to be hidden.

  $ cd ..
  $ hg clone base droplast
  updating to branch default
  3 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd droplast
  $ hg histedit -r '40db8afa467b' --commands - << EOF
  > pick 40db8afa467b 10 c
  > drop b449568bf7fc 11 f
  > EOF
  $ hg log -G
  @  12:40db8afa467b c
  |
  o  0:cb9a9f314b8b a
  

With rewritten ancestors

  $ echo e > e
  $ hg add e
  $ hg commit -m g
  $ echo f > f
  $ hg add f
  $ hg commit -m h
  $ hg histedit -r '40db8afa467b' --commands - << EOF
  > pick 47a8561c0449 12 g
  > pick 40db8afa467b 10 c
  > drop 1b3b05f35ff0 13 h
  > EOF
  $ hg log -G
  @  17:ee6544123ab8 c
  |
  o  16:269e713e9eae g
  |
  o  0:cb9a9f314b8b a
  
  $ cd ../base



Test phases support
===========================================

Check that histedit respect immutability
-------------------------------------------

  $ cat >> $HGRCPATH << EOF
  > [ui]
  > logtemplate= {rev}:{node|short} ({phase}) {desc|firstline}\n
  > EOF

  $ hg ph -pv '.^'
  phase changed for 2 changesets
  $ hg log -G
  @  13:b449568bf7fc (draft) f
  |
  o  12:40db8afa467b (public) c
  |
  o  0:cb9a9f314b8b (public) a
  
  $ hg histedit -r '.~2'
  abort: cannot edit public changeset: cb9a9f314b8b
  (see 'hg help phases' for details)
  [255]


Prepare further testing
-------------------------------------------

  $ for x in g h i j k ; do
  >     echo $x > $x
  >     hg add $x
  >     hg ci -m $x
  > done
  $ hg phase --force --secret .~2
  $ hg log -G
  @  18:ee118ab9fa44 (secret) k
  |
  o  17:3a6c53ee7f3d (secret) j
  |
  o  16:b605fb7503f2 (secret) i
  |
  o  15:7395e1ff83bd (draft) h
  |
  o  14:6b70183d2492 (draft) g
  |
  o  13:b449568bf7fc (draft) f
  |
  o  12:40db8afa467b (public) c
  |
  o  0:cb9a9f314b8b (public) a
  
  $ cd ..

simple phase conservation
-------------------------------------------

Resulting changeset should conserve the phase of the original one whatever the
phases.new-commit option is.

New-commit as draft (default)

  $ cp -R base simple-draft
  $ cd simple-draft
  $ hg histedit -r 'b449568bf7fc' --commands - << EOF
  > edit b449568bf7fc 11 f
  > pick 6b70183d2492 12 g
  > pick 7395e1ff83bd 13 h
  > pick b605fb7503f2 14 i
  > pick 3a6c53ee7f3d 15 j
  > pick ee118ab9fa44 16 k
  > EOF
  0 files updated, 0 files merged, 6 files removed, 0 files unresolved
  adding f
  Editing (b449568bf7fc), you may commit or record as needed now.
  (hg histedit --continue to resume)
  [1]
  $ echo f >> f
  $ hg histedit --continue
  $ hg log -G
  @  24:12e89af74238 (secret) k
  |
  o  23:636a8687b22e (secret) j
  |
  o  22:ccaf0a38653f (secret) i
  |
  o  21:11a89d1c2613 (draft) h
  |
  o  20:c1dec7ca82ea (draft) g
  |
  o  19:087281e68428 (draft) f
  |
  o  12:40db8afa467b (public) c
  |
  o  0:cb9a9f314b8b (public) a
  
  $ cd ..


New-commit as secret (config)

  $ cp -R base simple-secret
  $ cd simple-secret
  $ cat >> .hg/hgrc << EOF
  > [phases]
  > new-commit=secret
  > EOF
  $ hg histedit -r 'b449568bf7fc' --commands - << EOF
  > edit b449568bf7fc 11 f
  > pick 6b70183d2492 12 g
  > pick 7395e1ff83bd 13 h
  > pick b605fb7503f2 14 i
  > pick 3a6c53ee7f3d 15 j
  > pick ee118ab9fa44 16 k
  > EOF
  0 files updated, 0 files merged, 6 files removed, 0 files unresolved
  adding f
  Editing (b449568bf7fc), you may commit or record as needed now.
  (hg histedit --continue to resume)
  [1]
  $ echo f >> f
  $ hg histedit --continue
  $ hg log -G
  @  24:12e89af74238 (secret) k
  |
  o  23:636a8687b22e (secret) j
  |
  o  22:ccaf0a38653f (secret) i
  |
  o  21:11a89d1c2613 (draft) h
  |
  o  20:c1dec7ca82ea (draft) g
  |
  o  19:087281e68428 (draft) f
  |
  o  12:40db8afa467b (public) c
  |
  o  0:cb9a9f314b8b (public) a
  
  $ cd ..


Changeset reordering
-------------------------------------------

If a secret changeset is put before a draft one, all descendant should be secret.
It seems more important to present the secret phase.

  $ cp -R base reorder
  $ cd reorder
  $ hg histedit -r 'b449568bf7fc' --commands - << EOF
  > pick b449568bf7fc 11 f
  > pick 3a6c53ee7f3d 15 j
  > pick 6b70183d2492 12 g
  > pick b605fb7503f2 14 i
  > pick 7395e1ff83bd 13 h
  > pick ee118ab9fa44 16 k
  > EOF
  $ hg log -G
  @  23:558246857888 (secret) k
  |
  o  22:28bd44768535 (secret) h
  |
  o  21:d5395202aeb9 (secret) i
  |
  o  20:21edda8e341b (secret) g
  |
  o  19:5ab64f3a4832 (secret) j
  |
  o  13:b449568bf7fc (draft) f
  |
  o  12:40db8afa467b (public) c
  |
  o  0:cb9a9f314b8b (public) a
  
  $ cd ..

Changeset folding
-------------------------------------------

Folding a secret changeset with a draft one turn the result secret (again,
better safe than sorry). Folding between same phase changeset still works

Note that there is a few reordering in this series for more extensive test

  $ cp -R base folding
  $ cd folding
  $ cat >> .hg/hgrc << EOF
  > [phases]
  > new-commit=secret
  > EOF
  $ hg histedit -r 'b449568bf7fc' --commands - << EOF
  > pick 7395e1ff83bd 13 h
  > fold b449568bf7fc 11 f
  > pick 6b70183d2492 12 g
  > fold 3a6c53ee7f3d 15 j
  > pick b605fb7503f2 14 i
  > fold ee118ab9fa44 16 k
  > EOF
  $ hg log -G
  @  27:f9daec13fb98 (secret) i
  |
  o  24:49807617f46a (secret) g
  |
  o  21:050280826e04 (draft) h
  |
  o  12:40db8afa467b (public) c
  |
  o  0:cb9a9f314b8b (public) a
  
  $ hg co 49807617f46a
  0 files updated, 0 files merged, 2 files removed, 0 files unresolved
  $ echo wat >> wat
  $ hg add wat
  $ hg ci -m 'add wat'
  created new head
  $ hg merge f9daec13fb98
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg ci -m 'merge'
  $ echo not wat > wat
  $ hg ci -m 'modify wat'
  $ hg histedit 050280826e04
  abort: cannot edit history that contains merges
  [255]
  $ cd ..

Check abort behavior
-------------------------------------------

We checks that abort properly clean the repository so the same histedit can be
attempted later.

  $ cp -R base abort
  $ cd abort
  $ hg histedit -r 'b449568bf7fc' --commands - << EOF
  > pick b449568bf7fc 13 f
  > pick 7395e1ff83bd 15 h
  > pick 6b70183d2492 14 g
  > pick b605fb7503f2 16 i
  > roll 3a6c53ee7f3d 17 j
  > edit ee118ab9fa44 18 k
  > EOF
  Editing (ee118ab9fa44), you may commit or record as needed now.
  (hg histedit --continue to resume)
  [1]

  $ hg histedit --abort
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  saved backup bundle to $TESTTMP/abort/.hg/strip-backup/4dc06258baa6-dff4ef05-backup.hg

  $ hg log -G
  @  18:ee118ab9fa44 (secret) k
  |
  o  17:3a6c53ee7f3d (secret) j
  |
  o  16:b605fb7503f2 (secret) i
  |
  o  15:7395e1ff83bd (draft) h
  |
  o  14:6b70183d2492 (draft) g
  |
  o  13:b449568bf7fc (draft) f
  |
  o  12:40db8afa467b (public) c
  |
  o  0:cb9a9f314b8b (public) a
  
  $ hg histedit -r 'b449568bf7fc' --commands - << EOF --config experimental.evolution.track-operation=1
  > pick b449568bf7fc 13 f
  > pick 7395e1ff83bd 15 h
  > pick 6b70183d2492 14 g
  > pick b605fb7503f2 16 i
  > pick 3a6c53ee7f3d 17 j
  > edit ee118ab9fa44 18 k
  > EOF
  Editing (ee118ab9fa44), you may commit or record as needed now.
  (hg histedit --continue to resume)
  [1]
  $ hg histedit --continue --config experimental.evolution.track-operation=1
  $ hg log -G
  @  23:175d6b286a22 (secret) k
  |
  o  22:44ca09d59ae4 (secret) j
  |
  o  21:31747692a644 (secret) i
  |
  o  20:9985cd4f21fa (draft) g
  |
  o  19:4dc06258baa6 (draft) h
  |
  o  13:b449568bf7fc (draft) f
  |
  o  12:40db8afa467b (public) c
  |
  o  0:cb9a9f314b8b (public) a
  
  $ hg debugobsolete --rev .
  ee118ab9fa44ebb86be85996548b5517a39e5093 175d6b286a224c23f192e79a581ce83131a53fa2 0 (Thu Jan 01 00:00:00 1970 +0000) {'ef1': '4', 'operation': 'histedit', 'user': 'test'}