tests/test-resolve.t

revlog: change generaldelta delta parent heuristic

The old generaldelta heuristic was "if p1 (or p2) was closer than the last full text,
use it, otherwise use prev". This was problematic when a repo contained multiple
branches that were very different. If commits to branch A were pushed, and the
last full text was branch B, it would generate a fulltext. Then if branch B was
pushed, it would generate another fulltext. The problem is that the last
fulltext (and delta'ing against `prev` in general) has no correlation with the
contents of the incoming revision, and therefore will always have degenerate
cases.

According to the blame, that algorithm was chosen to minimize the chain length.
Since there is already code that protects against that (the delta-vs-fulltext
code), and since it has been improved since the original generaldelta algorithm
went in (2011), I believe the chain length criteria will still be preserved.

The new algorithm always diffs against p1 (or p2 if it's closer), unless the
resulting delta will fail the delta-vs-fulltext check, in which case we delta
against prev.

Some before and after stats on manifest.d size.

internal large repo
old heuristic - 2.0 GB
new heuristic - 1.2 GB

mozilla-central
old heuristic - 242 MB
new heuristic - 261 MB

The regression in mozilla central is due to the new heuristic choosing p2r as
the delta when it's closer to the tip. Switching the algorithm to always prefer
p1r brings the size back down (242 MB). This is result of the way in which
mozilla does merges and pushes, and the result could easily swing the other
direction in other repos (depending on if they merge X into Y or Y into X), but
will never be as degenerate as before.

I future patch will address the regression by introducing an optional, even more
aggressive delta heuristic which will knock the mozilla manifest size down
dramatically.

test that a commit clears the merge state.

  $ hg init repo
  $ cd repo

  $ echo foo > file1
  $ echo foo > file2
  $ hg commit -Am 'add files'
  adding file1
  adding file2

  $ echo bar >> file1
  $ echo bar >> file2
  $ hg commit -Am 'append bar to files'

create a second head with conflicting edits

  $ hg up -C 0
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ echo baz >> file1
  $ echo baz >> file2
  $ hg commit -Am 'append baz to files'
  created new head

create a third head with no conflicting edits
  $ hg up -qC 0
  $ echo foo > file3
  $ hg commit -Am 'add non-conflicting file'
  adding file3
  created new head

failing merge

  $ hg up -qC 2
  $ hg merge --tool=internal:fail 1
  0 files updated, 0 files merged, 0 files removed, 2 files unresolved
  use 'hg resolve' to retry unresolved file merges or 'hg update -C .' to abandon
  [1]

resolve -l should contain unresolved entries

  $ hg resolve -l
  U file1
  U file2

  $ hg resolve -l --no-status
  file1
  file2

resolving an unknown path should emit a warning, but not for -l

  $ hg resolve -m does-not-exist
  arguments do not match paths that need resolving
  $ hg resolve -l does-not-exist

resolve the failure

  $ echo resolved > file1
  $ hg resolve -m file1

resolve -l should show resolved file as resolved

  $ hg resolve -l
  R file1
  U file2

  $ hg resolve -l -Tjson
  [
   {
    "path": "file1",
    "status": "R"
   },
   {
    "path": "file2",
    "status": "U"
   }
  ]

resolve -m without paths should mark all resolved

  $ hg resolve -m
  (no more unresolved files)
  $ hg commit -m 'resolved'

resolve -l should be empty after commit

  $ hg resolve -l

  $ hg resolve -l -Tjson
  [
  ]

resolve --all should abort when no merge in progress

  $ hg resolve --all
  abort: resolve command not applicable when not merging
  [255]

resolve -m should abort when no merge in progress

  $ hg resolve -m
  abort: resolve command not applicable when not merging
  [255]

set up conflict-free merge

  $ hg up -qC 3
  $ hg merge 1
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)

resolve --all should do nothing in merge without conflicts
  $ hg resolve --all
  (no more unresolved files)

resolve -m should do nothing in merge without conflicts

  $ hg resolve -m
  (no more unresolved files)

get back to conflicting state

  $ hg up -qC 2
  $ hg merge --tool=internal:fail 1
  0 files updated, 0 files merged, 0 files removed, 2 files unresolved
  use 'hg resolve' to retry unresolved file merges or 'hg update -C .' to abandon
  [1]

resolve without arguments should suggest --all
  $ hg resolve
  abort: no files or directories specified
  (use --all to remerge all files)
  [255]

resolve --all should re-merge all unresolved files
  $ hg resolve -q --all
  warning: conflicts during merge.
  merging file1 incomplete! (edit conflicts, then use 'hg resolve --mark')
  warning: conflicts during merge.
  merging file2 incomplete! (edit conflicts, then use 'hg resolve --mark')
  [1]
  $ grep '<<<' file1 > /dev/null
  $ grep '<<<' file2 > /dev/null

resolve <file> should re-merge file
  $ echo resolved > file1
  $ hg resolve -q file1
  warning: conflicts during merge.
  merging file1 incomplete! (edit conflicts, then use 'hg resolve --mark')
  [1]
  $ grep '<<<' file1 > /dev/null

resolve <file> should do nothing if 'file' was marked resolved
  $ echo resolved > file1
  $ hg resolve -m file1
  $ hg resolve -q file1
  $ cat file1
  resolved

test crashed merge with empty mergestate

  $ hg up -qC 1
  $ mkdir .hg/merge
  $ touch .hg/merge/state

resolve -l should be empty

  $ hg resolve -l

  $ cd ..