view tests/test-revlog-v2.t @ 37865:da083d9fafab

shortest: don't keep checking for longer prefix if node doesn't exist (API)

If revlog.shortest() is called with an invalid nodeid, we keep
checking if longer and longer prefixes are valid. We call
revlog._partialmatch() for each prefix. That function will give us
None if the node doesn't exist (and a RevlogError if it's ambiguous),
so there's no need to keep checking.

This patch instead makes revlog.shortest() raise a LookupError is the
node does not exist, and updates the caller to handle it. Before this
patch, revlog.shortest() would return the full hexnode for nonexistent
nodeids. By the same reasoning as in 7b2955624777 (scmutil: make
shortesthexnodeidprefix() take a full binary nodeid, 2018-04-14), it's
not revlog.shortest() that should decide how to present nonexistent
nodeids, so that's now moved to the template function.

This should speed up cases where {shortest()} is applied to an invalid
nodeid, but I couldn't think of a reasonable case where that would
happen.

Differential Revision: https://phab.mercurial-scm.org/D3461

#require reporevlogstore

A repo with unknown revlogv2 requirement string cannot be opened

  $ hg init invalidreq
  $ cd invalidreq
  $ echo exp-revlogv2.unknown >> .hg/requires
  $ hg log
  abort: repository requires features unknown to this Mercurial: exp-revlogv2.unknown!
  (see https://mercurial-scm.org/wiki/MissingRequirement for more information)
  [255]
  $ cd ..

Can create and open repo with revlog v2 requirement

  $ cat >> $HGRCPATH << EOF
  > [experimental]
  > revlogv2 = enable-unstable-format-and-corrupt-my-data
  > EOF

  $ hg init empty-repo
  $ cd empty-repo
  $ cat .hg/requires
  dotencode
  exp-revlogv2.0
  fncache
  store

  $ hg log

Unknown flags to revlog are rejected

  >>> with open('.hg/store/00changelog.i', 'wb') as fh:
  ...     fh.write(b'\x00\x04\xde\xad')

  $ hg log
  abort: unknown flags (0x04) in version 57005 revlog 00changelog.i!
  [255]

  $ cd ..

Writing a simple revlog v2 works

  $ hg init simple
  $ cd simple
  $ touch foo
  $ hg -q commit -A -m initial

  $ hg log
  changeset:   0:96ee1d7354c4
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     initial
  
Header written as expected (changelog always disables generaldelta)

  $ f --hexdump --bytes 4 .hg/store/00changelog.i
  .hg/store/00changelog.i:
  0000: 00 01 de ad                                     |....|

  $ f --hexdump --bytes 4 .hg/store/data/foo.i
  .hg/store/data/foo.i:
  0000: 00 03 de ad                                     |....|