view tests/test-rename.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

  $ hg init
  $ mkdir d1 d1/d11 d2
  $ echo d1/a > d1/a
  $ echo d1/ba > d1/ba
  $ echo d1/a1 > d1/d11/a1
  $ echo d1/b > d1/b
  $ echo d2/b > d2/b
  $ hg add d1/a d1/b d1/ba d1/d11/a1 d2/b
  $ hg commit -m "1"

rename a single file

  $ hg rename d1/d11/a1 d2/c
  $ hg --config ui.portablefilenames=abort rename d1/a d1/con.xml
  abort: filename contains 'con', which is reserved on Windows: d1/con.xml
  [255]
  $ hg sum
  parent: 0:9b4b6e7b2c26 tip
   1
  branch: default
  commit: 1 renamed
  update: (current)
  phases: 1 draft
  $ hg status -C
  A d2/c
    d1/d11/a1
  R d1/d11/a1
  $ hg update -C
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ rm d2/c

rename a single file using absolute paths

  $ hg rename `pwd`/d1/d11/a1 `pwd`/d2/c
  $ hg status -C
  A d2/c
    d1/d11/a1
  R d1/d11/a1
  $ hg update -C
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ rm d2/c

rename --after a single file

  $ mv d1/d11/a1 d2/c
  $ hg rename --after d1/d11/a1 d2/c
  $ hg status -C
  A d2/c
    d1/d11/a1
  R d1/d11/a1
  $ hg update -C
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ rm d2/c

rename --after a single file when src and tgt already tracked

  $ mv d1/d11/a1 d2/c
  $ hg addrem -s 0
  removing d1/d11/a1
  adding d2/c
  $ hg rename --after d1/d11/a1 d2/c
  $ hg status -C
  A d2/c
    d1/d11/a1
  R d1/d11/a1
  $ hg update -C
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ rm d2/c

rename --after a single file to a nonexistent target filename

  $ hg rename --after d1/a dummy
  d1/a: not recording move - dummy does not exist
  [1]

move a single file to an existing directory

  $ hg rename d1/d11/a1 d2
  $ hg status -C
  A d2/a1
    d1/d11/a1
  R d1/d11/a1
  $ hg update -C
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ rm d2/a1

move --after a single file to an existing directory

  $ mv d1/d11/a1 d2
  $ hg rename --after d1/d11/a1 d2
  $ hg status -C
  A d2/a1
    d1/d11/a1
  R d1/d11/a1
  $ hg update -C
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ rm d2/a1

rename a file using a relative path

  $ (cd d1/d11; hg rename ../../d2/b e)
  $ hg status -C
  A d1/d11/e
    d2/b
  R d2/b
  $ hg update -C
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ rm d1/d11/e

rename --after a file using a relative path

  $ (cd d1/d11; mv ../../d2/b e; hg rename --after ../../d2/b e)
  $ hg status -C
  A d1/d11/e
    d2/b
  R d2/b
  $ hg update -C
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ rm d1/d11/e

rename directory d1 as d3

  $ hg rename d1/ d3
  moving d1/a to d3/a
  moving d1/b to d3/b
  moving d1/ba to d3/ba
  moving d1/d11/a1 to d3/d11/a1
  $ hg status -C
  A d3/a
    d1/a
  A d3/b
    d1/b
  A d3/ba
    d1/ba
  A d3/d11/a1
    d1/d11/a1
  R d1/a
  R d1/b
  R d1/ba
  R d1/d11/a1
  $ hg update -C
  4 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ rm -rf d3

rename --after directory d1 as d3

  $ mv d1 d3
  $ hg rename --after d1 d3
  moving d1/a to d3/a
  moving d1/b to d3/b
  moving d1/ba to d3/ba
  moving d1/d11/a1 to d3/d11/a1
  $ hg status -C
  A d3/a
    d1/a
  A d3/b
    d1/b
  A d3/ba
    d1/ba
  A d3/d11/a1
    d1/d11/a1
  R d1/a
  R d1/b
  R d1/ba
  R d1/d11/a1
  $ hg update -C
  4 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ rm -rf d3

move a directory using a relative path

  $ (cd d2; mkdir d3; hg rename ../d1/d11 d3)
  moving ../d1/d11/a1 to d3/d11/a1
  $ hg status -C
  A d2/d3/d11/a1
    d1/d11/a1
  R d1/d11/a1
  $ hg update -C
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ rm -rf d2/d3

move --after a directory using a relative path

  $ (cd d2; mkdir d3; mv ../d1/d11 d3; hg rename --after ../d1/d11 d3)
  moving ../d1/d11/a1 to d3/d11/a1
  $ hg status -C
  A d2/d3/d11/a1
    d1/d11/a1
  R d1/d11/a1
  $ hg update -C
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ rm -rf d2/d3

move directory d1/d11 to an existing directory d2 (removes empty d1)

  $ hg rename d1/d11/ d2
  moving d1/d11/a1 to d2/d11/a1
  $ hg status -C
  A d2/d11/a1
    d1/d11/a1
  R d1/d11/a1
  $ hg update -C
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ rm -rf d2/d11

move directories d1 and d2 to a new directory d3

  $ mkdir d3
  $ hg rename d1 d2 d3
  moving d1/a to d3/d1/a
  moving d1/b to d3/d1/b
  moving d1/ba to d3/d1/ba
  moving d1/d11/a1 to d3/d1/d11/a1
  moving d2/b to d3/d2/b
  $ hg status -C
  A d3/d1/a
    d1/a
  A d3/d1/b
    d1/b
  A d3/d1/ba
    d1/ba
  A d3/d1/d11/a1
    d1/d11/a1
  A d3/d2/b
    d2/b
  R d1/a
  R d1/b
  R d1/ba
  R d1/d11/a1
  R d2/b
  $ hg update -C
  5 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ rm -rf d3

move --after directories d1 and d2 to a new directory d3

  $ mkdir d3
  $ mv d1 d2 d3
  $ hg rename --after d1 d2 d3
  moving d1/a to d3/d1/a
  moving d1/b to d3/d1/b
  moving d1/ba to d3/d1/ba
  moving d1/d11/a1 to d3/d1/d11/a1
  moving d2/b to d3/d2/b
  $ hg status -C
  A d3/d1/a
    d1/a
  A d3/d1/b
    d1/b
  A d3/d1/ba
    d1/ba
  A d3/d1/d11/a1
    d1/d11/a1
  A d3/d2/b
    d2/b
  R d1/a
  R d1/b
  R d1/ba
  R d1/d11/a1
  R d2/b
  $ hg update -C
  5 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ rm -rf d3

move everything under directory d1 to existing directory d2, do not
overwrite existing files (d2/b)

  $ hg rename d1/* d2
  d2/b: not overwriting - file already committed
  ('hg rename --force' to replace the file by recording a rename)
  moving d1/d11/a1 to d2/d11/a1
  [1]
  $ hg status -C
  A d2/a
    d1/a
  A d2/ba
    d1/ba
  A d2/d11/a1
    d1/d11/a1
  R d1/a
  R d1/ba
  R d1/d11/a1
  $ diff -u d1/b d2/b
  --- d1/b	* (glob)
  +++ d2/b	* (glob)
  @@ * (glob)
  -d1/b
  +d2/b
  [1]
  $ hg update -C
  3 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ rm d2/a d2/ba d2/d11/a1

attempt to move one file into a non-existent directory

  $ hg rename d1/a dx/
  abort: destination dx/ is not a directory
  [255]
  $ hg status -C
  $ hg update -C
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved

attempt to move potentially more than one file into a non-existent directory

  $ hg rename 'glob:d1/**' dx
  abort: with multiple sources, destination must be an existing directory
  [255]

move every file under d1 to d2/d21

  $ mkdir d2/d21
  $ hg rename 'glob:d1/**' d2/d21
  moving d1/a to d2/d21/a
  moving d1/b to d2/d21/b
  moving d1/ba to d2/d21/ba
  moving d1/d11/a1 to d2/d21/a1
  $ hg status -C
  A d2/d21/a
    d1/a
  A d2/d21/a1
    d1/d11/a1
  A d2/d21/b
    d1/b
  A d2/d21/ba
    d1/ba
  R d1/a
  R d1/b
  R d1/ba
  R d1/d11/a1
  $ hg update -C
  4 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ rm -rf d2/d21

move --after some files under d1 to d2/d21

  $ mkdir d2/d21
  $ mv d1/a d1/d11/a1 d2/d21
  $ hg rename --after 'glob:d1/**' d2/d21
  moving d1/a to d2/d21/a
  d1/b: not recording move - d2/d21/b does not exist
  d1/ba: not recording move - d2/d21/ba does not exist
  moving d1/d11/a1 to d2/d21/a1
  [1]
  $ hg status -C
  A d2/d21/a
    d1/a
  A d2/d21/a1
    d1/d11/a1
  R d1/a
  R d1/d11/a1
  $ hg update -C
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ rm -rf d2/d21

move every file under d1 starting with an 'a' to d2/d21 (regexp)

  $ mkdir d2/d21
  $ hg rename 're:d1/([^a][^/]*/)*a.*' d2/d21
  moving d1/a to d2/d21/a
  moving d1/d11/a1 to d2/d21/a1
  $ hg status -C
  A d2/d21/a
    d1/a
  A d2/d21/a1
    d1/d11/a1
  R d1/a
  R d1/d11/a1
  $ hg update -C
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ rm -rf d2/d21

attempt to overwrite an existing file

  $ echo "ca" > d1/ca
  $ hg rename d1/ba d1/ca
  d1/ca: not overwriting - file exists
  ('hg rename --after' to record the rename)
  [1]
  $ hg status -C
  ? d1/ca
  $ hg update -C
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved

forced overwrite of an existing file

  $ echo "ca" > d1/ca
  $ hg rename --force d1/ba d1/ca
  $ hg status -C
  A d1/ca
    d1/ba
  R d1/ba
  $ hg update -C
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ rm d1/ca

attempt to overwrite an existing broken symlink

#if symlink
  $ ln -s ba d1/ca
  $ hg rename --traceback d1/ba d1/ca
  d1/ca: not overwriting - file exists
  ('hg rename --after' to record the rename)
  [1]
  $ hg status -C
  ? d1/ca
  $ hg update -C
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ rm d1/ca

replace a symlink with a file

  $ ln -s ba d1/ca
  $ hg rename --force d1/ba d1/ca
  $ hg status -C
  A d1/ca
    d1/ba
  R d1/ba
  $ hg update -C
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ rm d1/ca
#endif

do not copy more than one source file to the same destination file

  $ mkdir d3
  $ hg rename d1/* d2/* d3
  moving d1/d11/a1 to d3/d11/a1
  d3/b: not overwriting - d2/b collides with d1/b
  [1]
  $ hg status -C
  A d3/a
    d1/a
  A d3/b
    d1/b
  A d3/ba
    d1/ba
  A d3/d11/a1
    d1/d11/a1
  R d1/a
  R d1/b
  R d1/ba
  R d1/d11/a1
  $ hg update -C
  4 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ rm -rf d3

move a whole subtree with "hg rename ."

  $ mkdir d3
  $ (cd d1; hg rename . ../d3)
  moving a to ../d3/d1/a
  moving b to ../d3/d1/b
  moving ba to ../d3/d1/ba
  moving d11/a1 to ../d3/d1/d11/a1
  $ hg status -C
  A d3/d1/a
    d1/a
  A d3/d1/b
    d1/b
  A d3/d1/ba
    d1/ba
  A d3/d1/d11/a1
    d1/d11/a1
  R d1/a
  R d1/b
  R d1/ba
  R d1/d11/a1
  $ hg update -C
  4 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ rm -rf d3

move a whole subtree with "hg rename --after ."

  $ mkdir d3
  $ mv d1/* d3
  $ (cd d1; hg rename --after . ../d3)
  moving a to ../d3/a
  moving b to ../d3/b
  moving ba to ../d3/ba
  moving d11/a1 to ../d3/d11/a1
  $ hg status -C
  A d3/a
    d1/a
  A d3/b
    d1/b
  A d3/ba
    d1/ba
  A d3/d11/a1
    d1/d11/a1
  R d1/a
  R d1/b
  R d1/ba
  R d1/d11/a1
  $ hg update -C
  4 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ rm -rf d3

move the parent tree with "hg rename .."

  $ (cd d1/d11; hg rename .. ../../d3)
  moving ../a to ../../d3/a
  moving ../b to ../../d3/b
  moving ../ba to ../../d3/ba
  moving a1 to ../../d3/d11/a1
  $ hg status -C
  A d3/a
    d1/a
  A d3/b
    d1/b
  A d3/ba
    d1/ba
  A d3/d11/a1
    d1/d11/a1
  R d1/a
  R d1/b
  R d1/ba
  R d1/d11/a1
  $ hg update -C
  4 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ rm -rf d3

skip removed files

  $ hg remove d1/b
  $ hg rename d1 d3
  moving d1/a to d3/a
  moving d1/ba to d3/ba
  moving d1/d11/a1 to d3/d11/a1
  $ hg status -C
  A d3/a
    d1/a
  A d3/ba
    d1/ba
  A d3/d11/a1
    d1/d11/a1
  R d1/a
  R d1/b
  R d1/ba
  R d1/d11/a1
  $ hg update -C
  4 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ rm -rf d3

transitive rename

  $ hg rename d1/b d1/bb
  $ hg rename d1/bb d1/bc
  $ hg status -C
  A d1/bc
    d1/b
  R d1/b
  $ hg update -C
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ rm d1/bc

transitive rename --after

  $ hg rename d1/b d1/bb
  $ mv d1/bb d1/bc
  $ hg rename --after d1/bb d1/bc
  $ hg status -C
  A d1/bc
    d1/b
  R d1/b
  $ hg update -C
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ rm d1/bc

  $ echo "# idempotent renames (d1/b -> d1/bb followed by d1/bb -> d1/b)"
  # idempotent renames (d1/b -> d1/bb followed by d1/bb -> d1/b)
  $ hg rename d1/b d1/bb
  $ echo "some stuff added to d1/bb" >> d1/bb
  $ hg rename d1/bb d1/b
  $ hg status -C
  M d1/b
  $ hg update -C
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

overwriting with renames (issue1959)

  $ hg rename d1/a d1/c
  $ hg rename d1/b d1/a
  $ hg status -C
  M d1/a
    d1/b
  A d1/c
    d1/a
  R d1/b
  $ hg diff --git
  diff --git a/d1/a b/d1/a
  --- a/d1/a
  +++ b/d1/a
  @@ -1,1 +1,1 @@
  -d1/a
  +d1/b
  diff --git a/d1/b b/d1/b
  deleted file mode 100644
  --- a/d1/b
  +++ /dev/null
  @@ -1,1 +0,0 @@
  -d1/b
  diff --git a/d1/a b/d1/c
  copy from d1/a
  copy to d1/c
  $ hg update -C
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ rm d1/c # The file was marked as added, so 'hg update' action  was 'forget'

check illegal path components

  $ hg rename d1/d11/a1 .hg/foo
  abort: path contains illegal component: .hg/foo
  [255]
  $ hg status -C
  $ hg rename d1/d11/a1 ../foo
  abort: ../foo not under root '$TESTTMP'
  [255]
  $ hg status -C

  $ mv d1/d11/a1 .hg/foo
  $ hg rename --after d1/d11/a1 .hg/foo
  abort: path contains illegal component: .hg/foo
  [255]
  $ hg status -C
  ! d1/d11/a1
  $ hg update -C
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ rm .hg/foo

  $ hg rename d1/d11/a1 .hg
  abort: path contains illegal component: .hg/a1
  [255]
  $ hg --config extensions.largefiles= rename d1/d11/a1 .hg
  The fsmonitor extension is incompatible with the largefiles extension and has been disabled. (fsmonitor !)
  abort: path contains illegal component: .hg/a1
  [255]
  $ hg status -C
  $ hg rename d1/d11/a1 ..
  abort: ../a1 not under root '$TESTTMP'
  [255]
  $ hg --config extensions.largefiles= rename d1/d11/a1 ..
  The fsmonitor extension is incompatible with the largefiles extension and has been disabled. (fsmonitor !)
  abort: ../a1 not under root '$TESTTMP'
  [255]
  $ hg status -C

  $ mv d1/d11/a1 .hg
  $ hg rename --after d1/d11/a1 .hg
  abort: path contains illegal component: .hg/a1
  [255]
  $ hg status -C
  ! d1/d11/a1
  $ hg update -C
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ rm .hg/a1

  $ (cd d1/d11; hg rename ../../d2/b ../../.hg/foo)
  abort: path contains illegal component: .hg/foo
  [255]
  $ hg status -C
  $ (cd d1/d11; hg rename ../../d2/b ../../../foo)
  abort: ../../../foo not under root '$TESTTMP'
  [255]
  $ hg status -C

check that stat information such as mtime is preserved on rename - it's unclear
whether the `touch` and `stat` commands are portable, so we mimic them using
python.  Not all platforms support precision of even one-second granularity, so
we allow a rather generous fudge factor here; 1234567890 is 2009, and the
primary thing we care about is that it's not the machine's current time;
hopefully it's really unlikely for a machine to have such a broken clock that
this test fails. :)

  $ mkdir mtime
Create the file (as empty), then update its mtime and atime to be 1234567890.
  >>> import os
  >>> filename = "mtime/f"
  >>> mtime = 1234567890
  >>> open(filename, "w").close()
  >>> os.utime(filename, (mtime, mtime))
  $ hg ci -qAm 'add mtime dir'
"hg cp" does not preserve the mtime, so it should be newer than the 2009
timestamp.
  $ hg cp -q mtime mtime_cp
  >>> from __future__ import print_function
  >>> import os
  >>> filename = "mtime_cp/f"
  >>> print(os.stat(filename).st_mtime < 1234567999)
  False
"hg mv" preserves the mtime, so it should be ~equal to the 2009 timestamp
(modulo some fudge factor due to not every system supporting 1s-level
precision).
  $ hg mv -q mtime mtime_mv
  >>> from __future__ import print_function
  >>> import os
  >>> filename = "mtime_mv/f"
  >>> print(os.stat(filename).st_mtime < 1234567999)
  True