view tests/test-update-branches.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

# Construct the following history tree:
#
# @  5:e1bb631146ca  b1
# |
# o  4:a4fdb3b883c4 0:b608b9236435  b1
# |
# | o  3:4b57d2520816 1:44592833ba9f
# | |
# | | o  2:063f31070f65
# | |/
# | o  1:44592833ba9f
# |/
# o  0:b608b9236435

  $ mkdir b1
  $ cd b1
  $ hg init
  $ echo foo > foo
  $ echo zero > a
  $ hg init sub
  $ echo suba > sub/suba
  $ hg --cwd sub ci -Am addsuba
  adding suba
  $ echo 'sub = sub' > .hgsub
  $ hg ci -qAm0
  $ echo one > a ; hg ci -m1
  $ echo two > a ; hg ci -m2
  $ hg up -q 1
  $ echo three > a ; hg ci -qm3
  $ hg up -q 0
  $ hg branch -q b1
  $ echo four > a ; hg ci -qm4
  $ echo five > a ; hg ci -qm5

Initial repo state:

  $ hg log -G --template '{rev}:{node|short} {parents} {branches}\n'
  @  5:ff252e8273df  b1
  |
  o  4:d047485b3896 0:60829823a42a  b1
  |
  | o  3:6efa171f091b 1:0786582aa4b1
  | |
  | | o  2:bd10386d478c
  | |/
  | o  1:0786582aa4b1
  |/
  o  0:60829823a42a
  

Make sure update doesn't assume b1 is a repository if invoked from outside:

  $ cd ..
  $ hg update b1
  abort: no repository found in '$TESTTMP' (.hg not found)!
  [255]
  $ cd b1

Test helper functions:

  $ revtest () {
  >     msg=$1
  >     dirtyflag=$2   # 'clean', 'dirty' or 'dirtysub'
  >     startrev=$3
  >     targetrev=$4
  >     opt=$5
  >     hg up -qC $startrev
  >     test $dirtyflag = dirty && echo dirty > foo
  >     test $dirtyflag = dirtysub && echo dirty > sub/suba
  >     hg up $opt $targetrev
  >     hg parent --template 'parent={rev}\n'
  >     hg stat -S
  > }

  $ norevtest () {
  >     msg=$1
  >     dirtyflag=$2   # 'clean', 'dirty' or 'dirtysub'
  >     startrev=$3
  >     opt=$4
  >     hg up -qC $startrev
  >     test $dirtyflag = dirty && echo dirty > foo
  >     test $dirtyflag = dirtysub && echo dirty > sub/suba
  >     hg up $opt
  >     hg parent --template 'parent={rev}\n'
  >     hg stat -S
  > }

Test cases are documented in a table in the update function of merge.py.
Cases are run as shown in that table, row by row.

  $ norevtest 'none clean linear' clean 4
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  parent=5

  $ norevtest 'none clean same'   clean 2
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  updated to "bd10386d478c: 2"
  1 other heads for branch "default"
  parent=2


  $ revtest 'none clean linear' clean 1 2
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  parent=2

  $ revtest 'none clean same'   clean 2 3
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  parent=3

  $ revtest 'none clean cross'  clean 3 4
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  parent=4


  $ revtest 'none dirty linear' dirty 1 2
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  parent=2
  M foo

  $ revtest 'none dirtysub linear' dirtysub 1 2
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  parent=2
  M sub/suba

  $ revtest 'none dirty same'   dirty 2 3
  abort: uncommitted changes
  (commit or update --clean to discard changes)
  parent=2
  M foo

  $ revtest 'none dirtysub same'   dirtysub 2 3
  abort: uncommitted changes
  (commit or update --clean to discard changes)
  parent=2
  M sub/suba

  $ revtest 'none dirty cross'  dirty 3 4
  abort: uncommitted changes
  (commit or update --clean to discard changes)
  parent=3
  M foo

  $ norevtest 'none dirty cross'  dirty 2
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  updated to "bd10386d478c: 2"
  1 other heads for branch "default"
  parent=2
  M foo

  $ revtest 'none dirtysub cross'  dirtysub 3 4
  abort: uncommitted changes
  (commit or update --clean to discard changes)
  parent=3
  M sub/suba

  $ revtest '-C dirty linear'   dirty 1 2 -C
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  parent=2

  $ revtest '-c dirty linear'   dirty 1 2 -c
  abort: uncommitted changes
  parent=1
  M foo

  $ revtest '-m dirty linear'   dirty 1 2 -m
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  parent=2
  M foo

  $ revtest '-m dirty cross'  dirty 3 4 -m
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  parent=4
  M foo

  $ revtest '-c dirtysub linear'   dirtysub 1 2 -c
  abort: uncommitted changes in subrepository "sub"
  parent=1
  M sub/suba

  $ norevtest '-c clean same'   clean 2 -c
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  updated to "bd10386d478c: 2"
  1 other heads for branch "default"
  parent=2

  $ revtest '-cC dirty linear'  dirty 1 2 -cC
  abort: can only specify one of -C/--clean, -c/--check, or -m/--merge
  parent=1
  M foo

  $ revtest '-mc dirty linear'  dirty 1 2 -mc
  abort: can only specify one of -C/--clean, -c/--check, or -m/--merge
  parent=1
  M foo

  $ revtest '-mC dirty linear'  dirty 1 2 -mC
  abort: can only specify one of -C/--clean, -c/--check, or -m/--merge
  parent=1
  M foo

  $ echo '[commands]' >> .hg/hgrc
  $ echo 'update.check = abort' >> .hg/hgrc

  $ revtest 'none dirty linear' dirty 1 2
  abort: uncommitted changes
  parent=1
  M foo

  $ revtest 'none dirty linear' dirty 1 2 -c
  abort: uncommitted changes
  parent=1
  M foo

  $ revtest 'none dirty linear' dirty 1 2 -C
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  parent=2

  $ echo 'update.check = none' >> .hg/hgrc

  $ revtest 'none dirty cross'  dirty 3 4
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  parent=4
  M foo

  $ revtest 'none dirty linear' dirty 1 2
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  parent=2
  M foo

  $ revtest 'none dirty linear' dirty 1 2 -c
  abort: uncommitted changes
  parent=1
  M foo

  $ revtest 'none dirty linear' dirty 1 2 -C
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  parent=2

  $ hg co -qC 3
  $ echo dirty >> a
  $ hg co --tool :merge3 4
  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
  [1]
  $ hg st
  M a
  ? a.orig
  $ cat a
  <<<<<<< working copy: 6efa171f091b - test: 3
  three
  dirty
  ||||||| base
  three
  =======
  four
  >>>>>>> destination:  d047485b3896 b1 - test: 4
  $ rm a.orig

  $ echo 'update.check = noconflict' >> .hg/hgrc

  $ revtest 'none dirty cross'  dirty 3 4
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  parent=4
  M foo

  $ revtest 'none dirty linear' dirty 1 2
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  parent=2
  M foo

  $ revtest 'none dirty linear' dirty 1 2 -c
  abort: uncommitted changes
  parent=1
  M foo

  $ revtest 'none dirty linear' dirty 1 2 -C
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  parent=2

Locally added file is allowed
  $ hg up -qC 3
  $ echo a > bar
  $ hg add bar
  $ hg up -q 4
  $ hg st
  A bar
  $ hg forget bar
  $ rm bar

Locally removed file is allowed
  $ hg up -qC 3
  $ hg rm foo
  $ hg up -q 4

File conflict is not allowed
  $ hg up -qC 3
  $ echo dirty >> a
  $ hg up -q 4
  abort: conflicting changes
  (commit or update --clean to discard changes)
  [255]
  $ hg up -m 4
  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
  [1]
  $ rm a.orig

Change/delete conflict is not allowed
  $ hg up -qC 3
  $ hg rm foo
  $ hg up -q 4

Uses default value of "linear" when value is misspelled
  $ echo 'update.check = linyar' >> .hg/hgrc

  $ revtest 'dirty cross'  dirty 3 4
  abort: uncommitted changes
  (commit or update --clean to discard changes)
  parent=3
  M foo

Setup for later tests
  $ revtest 'none dirty linear' dirty 1 2 -c
  abort: uncommitted changes
  parent=1
  M foo

  $ cd ..

Test updating to null revision

  $ hg init null-repo
  $ cd null-repo
  $ echo a > a
  $ hg add a
  $ hg ci -m a
  $ hg up -qC 0
  $ echo b > b
  $ hg add b
  $ hg up null
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ hg st
  A b
  $ hg up -q 0
  $ hg st
  A b
  $ hg up -qC null
  $ hg st
  ? b
  $ cd ..

Test updating with closed head
---------------------------------------------------------------------

  $ hg clone -U -q b1 closed-heads
  $ cd closed-heads

Test updating if at least one non-closed branch head exists

if on the closed branch head:
- update to "."
- "updated to a closed branch head ...." message is displayed
- "N other heads for ...." message is displayed

  $ hg update -q -C 3
  $ hg commit --close-branch -m 6
  $ norevtest "on closed branch head" clean 6
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  no open descendant heads on branch "default", updating to a closed head
  (committing will reopen the head, use 'hg heads .' to see 1 other heads)
  parent=6

if descendant non-closed branch head exists, and it is only one branch head:
- update to it, even if its revision is less than closed one
- "N other heads for ...." message isn't displayed

  $ norevtest "non-closed 2 should be chosen" clean 1
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  parent=2

if all descendant branch heads are closed, but there is another branch head:
- update to the tipmost descendant head
- "updated to a closed branch head ...." message is displayed
- "N other heads for ...." message is displayed

  $ norevtest "all descendant branch heads are closed" clean 3
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  no open descendant heads on branch "default", updating to a closed head
  (committing will reopen the head, use 'hg heads .' to see 1 other heads)
  parent=6

Test updating if all branch heads are closed

if on the closed branch head:
- update to "."
- "updated to a closed branch head ...." message is displayed
- "all heads of branch ...." message is displayed

  $ hg update -q -C 2
  $ hg commit --close-branch -m 7
  $ norevtest "all heads of branch default are closed" clean 6
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  no open descendant heads on branch "default", updating to a closed head
  (committing will reopen branch "default")
  parent=6

if not on the closed branch head:
- update to the tipmost descendant (closed) head
- "updated to a closed branch head ...." message is displayed
- "all heads of branch ...." message is displayed

  $ norevtest "all heads of branch default are closed" clean 1
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  no open descendant heads on branch "default", updating to a closed head
  (committing will reopen branch "default")
  parent=7

  $ cd ..

Test updating if "default" branch doesn't exist and no revision is
checked out (= "default" is used as current branch)

  $ hg init no-default-branch
  $ cd no-default-branch

  $ hg branch foobar
  marked working directory as branch foobar
  (branches are permanent and global, did you want a bookmark?)
  $ echo a > a
  $ hg commit -m "#0" -A
  adding a
  $ echo 1 >> a
  $ hg commit -m "#1"
  $ hg update -q 0
  $ echo 3 >> a
  $ hg commit -m "#2"
  created new head
  $ hg commit --close-branch -m "#3"

if there is at least one non-closed branch head:
- update to the tipmost branch head

  $ norevtest "non-closed 1 should be chosen" clean null
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  parent=1

if all branch heads are closed
- update to "tip"
- "updated to a closed branch head ...." message is displayed
- "all heads for branch "XXXX" are closed" message is displayed

  $ hg update -q -C 1
  $ hg commit --close-branch -m "#4"

  $ norevtest "all branches are closed" clean null
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  no open descendant heads on branch "foobar", updating to a closed head
  (committing will reopen branch "foobar")
  parent=4

  $ cd ../b1

Test obsolescence behavior
---------------------------------------------------------------------

successors should be taken in account when checking head destination

  $ cat << EOF >> $HGRCPATH
  > [ui]
  > logtemplate={rev}:{node|short} {desc|firstline}
  > [experimental]
  > evolution.createmarkers=True
  > EOF

Test no-argument update to a successor of an obsoleted changeset

  $ hg log -G
  o  5:ff252e8273df 5
  |
  o  4:d047485b3896 4
  |
  | o  3:6efa171f091b 3
  | |
  | | o  2:bd10386d478c 2
  | |/
  | @  1:0786582aa4b1 1
  |/
  o  0:60829823a42a 0
  
  $ hg book bm -r 3
  $ hg status
  M foo

We add simple obsolescence marker between 3 and 4 (indirect successors)

  $ hg id --debug -i -r 3
  6efa171f091b00a3c35edc15d48c52a498929953
  $ hg id --debug -i -r 4
  d047485b3896813b2a624e86201983520f003206
  $ hg debugobsolete 6efa171f091b00a3c35edc15d48c52a498929953 aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
  obsoleted 1 changesets
  $ hg debugobsolete aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa d047485b3896813b2a624e86201983520f003206

Test that 5 is detected as a valid destination from 3 and also accepts moving
the bookmark (issue4015)

  $ hg up --quiet --hidden 3
  $ hg up 5
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg book bm
  moving bookmark 'bm' forward from 6efa171f091b
  $ hg bookmarks
   * bm                        5:ff252e8273df

Test that we abort before we warn about the hidden commit if the working
directory is dirty
  $ echo conflict > a
  $ hg up --hidden 3
  abort: uncommitted changes
  (commit or update --clean to discard changes)
  [255]

Test that we still warn also when there are conflicts
  $ hg up -m --hidden 3
  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
  (leaving bookmark bm)
  updated to hidden changeset 6efa171f091b
  (hidden revision '6efa171f091b' was rewritten as: d047485b3896)
  [1]
  $ hg revert -r . a
  $ hg resolve -m
  (no more unresolved files)

Test that 4 is detected as the no-argument destination from 3 and also moves
the bookmark with it
  $ hg up --quiet 0          # we should be able to update to 3 directly
  $ hg up --quiet --hidden 3 # but not implemented yet.
  updated to hidden changeset 6efa171f091b
  (hidden revision '6efa171f091b' was rewritten as: d047485b3896)
  $ hg book -f bm
  $ hg up
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  updating bookmark bm
  $ hg book
   * bm                        4:d047485b3896

Test that 5 is detected as a valid destination from 1
  $ hg up --quiet 0          # we should be able to update to 3 directly
  $ hg up --quiet --hidden 3 # but not implemented yet.
  updated to hidden changeset 6efa171f091b
  (hidden revision '6efa171f091b' was rewritten as: d047485b3896)
  $ hg up 5
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

Test that 5 is not detected as a valid destination from 2
  $ hg up --quiet 0
  $ hg up --quiet 2
  $ hg up 5
  abort: uncommitted changes
  (commit or update --clean to discard changes)
  [255]

Test that we don't crash when updating from a pruned changeset (i.e. has no
successors). Behavior should probably be that we update to the first
non-obsolete parent but that will be decided later.
  $ hg id --debug -r 2
  bd10386d478cd5a9faf2e604114c8e6da62d3889
  $ hg up --quiet 0
  $ hg up --quiet 2
  $ hg debugobsolete bd10386d478cd5a9faf2e604114c8e6da62d3889
  obsoleted 1 changesets
  $ hg up
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved

Test experimental revset support

  $ hg log -r '_destupdate()'
  2:bd10386d478c 2 (no-eol)

Test that boolean flags allow --no-flag specification to override [defaults]
  $ cat >> $HGRCPATH <<EOF
  > [defaults]
  > update = --check
  > EOF
  $ hg co 2
  abort: uncommitted changes
  [255]
  $ hg co --no-check 2
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved