tests/test-convert.t

commit: improve the files field of changelog for merges

Currently, the files list of merge commits repeats all the deletions
(either actual deletions, or files that got renamed) that happened
between base and p2 of the merge. If p2 is the main branch, the list
can easily be much bigger than the change being merged.

This results in various problems worth improving:
- changelog is bigger than necessary
- `hg log directory` lists many unrelated merge commits, and `hg log
  -v -r commit` frequently fills multiple screens worth of files
- it possibly slows down adjustlinkrev, by forcing it to read more
  manifests, and that function can certainly be a bottleneck
- the server side of pulls can waste a lot of time simply opening the
  filelogs for pointless files (the constant factors for opening even
  a tiny filelog is apparently pretty bad)

So stop listing such files as described in the code.  Impacted merge
commits and their descendants get a different hash than they would
have without this. This doesn't seem problematic, except for
convert. The previous commit helped with that in the hg->hg case (but
if you do svn->hg twice from scratch, hashes can still change).

The rest of the description is numbers. I don't have much to report,
because recreating the files list of existing repositories is not
easy:
- debugupgradeformat and bundle/unbundle don't recreate the list
- export/import tends to choke quickly applying patches or on
  description that contain diffs,
- merge commits from the convert extension don't have the right files
  list for reasons orthogonal to the current commit
- replaying the merge with hg update/hg merge/hg revert --all/hg
  commit can end up failing in hg revert
- I wasn't sure that using debugsetparents + debugrebuilddirstate
  would really build the right thing

I measured commit time before and after this change, in a case with no
files filtered out, several files filtered out (no difference) and 5k
files filtered out (+1% time).

Recreating the 100 more recent merges in a private repo, the
concatenated uncompressed files lists goes from 1.12MB to
0.52MB. Excluding 3 merges that are not representative, then the size
goes from 570k to 15k.
I converted part of mozilla-central, and observed file list shrinking
quite a bit too, starting at the very first merge, 733641d9feaf, going
from 550 files to 10 files (although they have relatively few merges,
so they probably wouldn't care).

Differential Revision: https://phab.mercurial-scm.org/D6613

  $ cat >> $HGRCPATH <<EOF
  > [extensions]
  > convert=
  > [convert]
  > hg.saverev=False
  > EOF
  $ hg help convert
  hg convert [OPTION]... SOURCE [DEST [REVMAP]]
  
  convert a foreign SCM repository to a Mercurial one.
  
      Accepted source formats [identifiers]:
  
      - Mercurial [hg]
      - CVS [cvs]
      - Darcs [darcs]
      - git [git]
      - Subversion [svn]
      - Monotone [mtn]
      - GNU Arch [gnuarch]
      - Bazaar [bzr]
      - Perforce [p4]
  
      Accepted destination formats [identifiers]:
  
      - Mercurial [hg]
      - Subversion [svn] (history on branches is not preserved)
  
      If no revision is given, all revisions will be converted. Otherwise,
      convert will only import up to the named revision (given in a format
      understood by the source).
  
      If no destination directory name is specified, it defaults to the basename
      of the source with "-hg" appended. If the destination repository doesn't
      exist, it will be created.
  
      By default, all sources except Mercurial will use --branchsort. Mercurial
      uses --sourcesort to preserve original revision numbers order. Sort modes
      have the following effects:
  
      --branchsort  convert from parent to child revision when possible, which
                    means branches are usually converted one after the other.
                    It generates more compact repositories.
      --datesort    sort revisions by date. Converted repositories have good-
                    looking changelogs but are often an order of magnitude
                    larger than the same ones generated by --branchsort.
      --sourcesort  try to preserve source revisions order, only supported by
                    Mercurial sources.
      --closesort   try to move closed revisions as close as possible to parent
                    branches, only supported by Mercurial sources.
  
      If "REVMAP" isn't given, it will be put in a default location
      ("<dest>/.hg/shamap" by default). The "REVMAP" is a simple text file that
      maps each source commit ID to the destination ID for that revision, like
      so:
  
        <source ID> <destination ID>
  
      If the file doesn't exist, it's automatically created. It's updated on
      each commit copied, so 'hg convert' can be interrupted and can be run
      repeatedly to copy new commits.
  
      The authormap is a simple text file that maps each source commit author to
      a destination commit author. It is handy for source SCMs that use unix
      logins to identify authors (e.g.: CVS). One line per author mapping and
      the line format is:
  
        source author = destination author
  
      Empty lines and lines starting with a "#" are ignored.
  
      The filemap is a file that allows filtering and remapping of files and
      directories. Each line can contain one of the following directives:
  
        include path/to/file-or-dir
  
        exclude path/to/file-or-dir
  
        rename path/to/source path/to/destination
  
      Comment lines start with "#". A specified path matches if it equals the
      full relative name of a file or one of its parent directories. The
      "include" or "exclude" directive with the longest matching path applies,
      so line order does not matter.
  
      The "include" directive causes a file, or all files under a directory, to
      be included in the destination repository. The default if there are no
      "include" statements is to include everything. If there are any "include"
      statements, nothing else is included. The "exclude" directive causes files
      or directories to be omitted. The "rename" directive renames a file or
      directory if it is converted. To rename from a subdirectory into the root
      of the repository, use "." as the path to rename to.
  
      "--full" will make sure the converted changesets contain exactly the right
      files with the right content. It will make a full conversion of all files,
      not just the ones that have changed. Files that already are correct will
      not be changed. This can be used to apply filemap changes when converting
      incrementally. This is currently only supported for Mercurial and
      Subversion.
  
      The splicemap is a file that allows insertion of synthetic history,
      letting you specify the parents of a revision. This is useful if you want
      to e.g. give a Subversion merge two parents, or graft two disconnected
      series of history together. Each entry contains a key, followed by a
      space, followed by one or two comma-separated values:
  
        key parent1, parent2
  
      The key is the revision ID in the source revision control system whose
      parents should be modified (same format as a key in .hg/shamap). The
      values are the revision IDs (in either the source or destination revision
      control system) that should be used as the new parents for that node. For
      example, if you have merged "release-1.0" into "trunk", then you should
      specify the revision on "trunk" as the first parent and the one on the
      "release-1.0" branch as the second.
  
      The branchmap is a file that allows you to rename a branch when it is
      being brought in from whatever external repository. When used in
      conjunction with a splicemap, it allows for a powerful combination to help
      fix even the most badly mismanaged repositories and turn them into nicely
      structured Mercurial repositories. The branchmap contains lines of the
      form:
  
        original_branch_name new_branch_name
  
      where "original_branch_name" is the name of the branch in the source
      repository, and "new_branch_name" is the name of the branch is the
      destination repository. No whitespace is allowed in the new branch name.
      This can be used to (for instance) move code in one repository from
      "default" to a named branch.
  
      Mercurial Source
      ################
  
      The Mercurial source recognizes the following configuration options, which
      you can set on the command line with "--config":
  
      convert.hg.ignoreerrors
                    ignore integrity errors when reading. Use it to fix
                    Mercurial repositories with missing revlogs, by converting
                    from and to Mercurial. Default is False.
      convert.hg.saverev
                    store original revision ID in changeset (forces target IDs
                    to change). It takes a boolean argument and defaults to
                    False.
      convert.hg.startrev
                    specify the initial Mercurial revision. The default is 0.
      convert.hg.revs
                    revset specifying the source revisions to convert.
  
      Bazaar Source
      #############
  
      The following options can be used with "--config":
  
      convert.bzr.saverev
                    whether to store the original Bazaar commit ID in the
                    metadata of the destination commit. The default is True.
  
      CVS Source
      ##########
  
      CVS source will use a sandbox (i.e. a checked-out copy) from CVS to
      indicate the starting point of what will be converted. Direct access to
      the repository files is not needed, unless of course the repository is
      ":local:". The conversion uses the top level directory in the sandbox to
      find the CVS repository, and then uses CVS rlog commands to find files to
      convert. This means that unless a filemap is given, all files under the
      starting directory will be converted, and that any directory
      reorganization in the CVS sandbox is ignored.
  
      The following options can be used with "--config":
  
      convert.cvsps.cache
                    Set to False to disable remote log caching, for testing and
                    debugging purposes. Default is True.
      convert.cvsps.fuzz
                    Specify the maximum time (in seconds) that is allowed
                    between commits with identical user and log message in a
                    single changeset. When very large files were checked in as
                    part of a changeset then the default may not be long enough.
                    The default is 60.
      convert.cvsps.logencoding
                    Specify encoding name to be used for transcoding CVS log
                    messages. Multiple encoding names can be specified as a list
                    (see 'hg help config.Syntax'), but only the first acceptable
                    encoding in the list is used per CVS log entries. This
                    transcoding is executed before cvslog hook below.
      convert.cvsps.mergeto
                    Specify a regular expression to which commit log messages
                    are matched. If a match occurs, then the conversion process
                    will insert a dummy revision merging the branch on which
                    this log message occurs to the branch indicated in the
                    regex. Default is "{{mergetobranch ([-\w]+)}}"
      convert.cvsps.mergefrom
                    Specify a regular expression to which commit log messages
                    are matched. If a match occurs, then the conversion process
                    will add the most recent revision on the branch indicated in
                    the regex as the second parent of the changeset. Default is
                    "{{mergefrombranch ([-\w]+)}}"
      convert.localtimezone
                    use local time (as determined by the TZ environment
                    variable) for changeset date/times. The default is False
                    (use UTC).
      hooks.cvslog  Specify a Python function to be called at the end of
                    gathering the CVS log. The function is passed a list with
                    the log entries, and can modify the entries in-place, or add
                    or delete them.
      hooks.cvschangesets
                    Specify a Python function to be called after the changesets
                    are calculated from the CVS log. The function is passed a
                    list with the changeset entries, and can modify the
                    changesets in-place, or add or delete them.
  
      An additional "debugcvsps" Mercurial command allows the builtin changeset
      merging code to be run without doing a conversion. Its parameters and
      output are similar to that of cvsps 2.1. Please see the command help for
      more details.
  
      Subversion Source
      #################
  
      Subversion source detects classical trunk/branches/tags layouts. By
      default, the supplied "svn://repo/path/" source URL is converted as a
      single branch. If "svn://repo/path/trunk" exists it replaces the default
      branch. If "svn://repo/path/branches" exists, its subdirectories are
      listed as possible branches. If "svn://repo/path/tags" exists, it is
      looked for tags referencing converted branches. Default "trunk",
      "branches" and "tags" values can be overridden with following options. Set
      them to paths relative to the source URL, or leave them blank to disable
      auto detection.
  
      The following options can be set with "--config":
  
      convert.svn.branches
                    specify the directory containing branches. The default is
                    "branches".
      convert.svn.tags
                    specify the directory containing tags. The default is
                    "tags".
      convert.svn.trunk
                    specify the name of the trunk branch. The default is
                    "trunk".
      convert.localtimezone
                    use local time (as determined by the TZ environment
                    variable) for changeset date/times. The default is False
                    (use UTC).
  
      Source history can be retrieved starting at a specific revision, instead
      of being integrally converted. Only single branch conversions are
      supported.
  
      convert.svn.startrev
                    specify start Subversion revision number. The default is 0.
  
      Git Source
      ##########
  
      The Git importer converts commits from all reachable branches (refs in
      refs/heads) and remotes (refs in refs/remotes) to Mercurial. Branches are
      converted to bookmarks with the same name, with the leading 'refs/heads'
      stripped. Git submodules are converted to Git subrepos in Mercurial.
  
      The following options can be set with "--config":
  
      convert.git.similarity
                    specify how similar files modified in a commit must be to be
                    imported as renames or copies, as a percentage between "0"
                    (disabled) and "100" (files must be identical). For example,
                    "90" means that a delete/add pair will be imported as a
                    rename if more than 90% of the file hasn't changed. The
                    default is "50".
      convert.git.findcopiesharder
                    while detecting copies, look at all files in the working
                    copy instead of just changed ones. This is very expensive
                    for large projects, and is only effective when
                    "convert.git.similarity" is greater than 0. The default is
                    False.
      convert.git.renamelimit
                    perform rename and copy detection up to this many changed
                    files in a commit. Increasing this will make rename and copy
                    detection more accurate but will significantly slow down
                    computation on large projects. The option is only relevant
                    if "convert.git.similarity" is greater than 0. The default
                    is "400".
      convert.git.committeractions
                    list of actions to take when processing author and committer
                    values.
  
          Git commits have separate author (who wrote the commit) and committer
          (who applied the commit) fields. Not all destinations support separate
          author and committer fields (including Mercurial). This config option
          controls what to do with these author and committer fields during
          conversion.
  
          A value of "messagedifferent" will append a "committer: ..." line to
          the commit message if the Git committer is different from the author.
          The prefix of that line can be specified using the syntax
          "messagedifferent=<prefix>". e.g. "messagedifferent=git-committer:".
          When a prefix is specified, a space will always be inserted between
          the prefix and the value.
  
          "messagealways" behaves like "messagedifferent" except it will always
          result in a "committer: ..." line being appended to the commit
          message. This value is mutually exclusive with "messagedifferent".
  
          "dropcommitter" will remove references to the committer. Only
          references to the author will remain. Actions that add references to
          the committer will have no effect when this is set.
  
          "replaceauthor" will replace the value of the author field with the
          committer. Other actions that add references to the committer will
          still take effect when this is set.
  
          The default is "messagedifferent".
  
      convert.git.extrakeys
                    list of extra keys from commit metadata to copy to the
                    destination. Some Git repositories store extra metadata in
                    commits. By default, this non-default metadata will be lost
                    during conversion. Setting this config option can retain
                    that metadata. Some built-in keys such as "parent" and
                    "branch" are not allowed to be copied.
      convert.git.remoteprefix
                    remote refs are converted as bookmarks with
                    "convert.git.remoteprefix" as a prefix followed by a /. The
                    default is 'remote'.
      convert.git.saverev
                    whether to store the original Git commit ID in the metadata
                    of the destination commit. The default is True.
      convert.git.skipsubmodules
                    does not convert root level .gitmodules files or files with
                    160000 mode indicating a submodule. Default is False.
  
      Perforce Source
      ###############
  
      The Perforce (P4) importer can be given a p4 depot path or a client
      specification as source. It will convert all files in the source to a flat
      Mercurial repository, ignoring labels, branches and integrations. Note
      that when a depot path is given you then usually should specify a target
      directory, because otherwise the target may be named "...-hg".
  
      The following options can be set with "--config":
  
      convert.p4.encoding
                    specify the encoding to use when decoding standard output of
                    the Perforce command line tool. The default is default
                    system encoding.
      convert.p4.startrev
                    specify initial Perforce revision (a Perforce changelist
                    number).
  
      Mercurial Destination
      #####################
  
      The Mercurial destination will recognize Mercurial subrepositories in the
      destination directory, and update the .hgsubstate file automatically if
      the destination subrepositories contain the <dest>/<sub>/.hg/shamap file.
      Converting a repository with subrepositories requires converting a single
      repository at a time, from the bottom up.
  
      The following options are supported:
  
      convert.hg.clonebranches
                    dispatch source branches in separate clones. The default is
                    False.
      convert.hg.tagsbranch
                    branch name for tag revisions, defaults to "default".
      convert.hg.usebranchnames
                    preserve branch names. The default is True.
      convert.hg.sourcename
                    records the given string as a 'convert_source' extra value
                    on each commit made in the target repository. The default is
                    None.
      convert.hg.preserve-hash
                    only works with mercurial sources. Make convert prevent
                    performance improvement to the list of modified files in
                    commits when such an improvement would cause the hash of a
                    commit to change. The default is False.
  
      All Destinations
      ################
  
      All destination types accept the following options:
  
      convert.skiptags
                    does not convert tags from the source repo to the target
                    repo. The default is False.
  
  options ([+] can be repeated):
  
   -s --source-type TYPE source repository type
   -d --dest-type TYPE   destination repository type
   -r --rev REV [+]      import up to source revision REV
   -A --authormap FILE   remap usernames using this file
      --filemap FILE     remap file names using contents of file
      --full             apply filemap changes by converting all files again
      --splicemap FILE   splice synthesized history into place
      --branchmap FILE   change branch names while converting
      --branchsort       try to sort changesets by branches
      --datesort         try to sort changesets by date
      --sourcesort       preserve source changesets order
      --closesort        try to reorder closed revisions
  
  (some details hidden, use --verbose to show complete help)
  $ hg init a
  $ cd a
  $ echo a > a
  $ hg ci -d'0 0' -Ama
  adding a
  $ hg cp a b
  $ hg ci -d'1 0' -mb
  $ hg rm a
  $ hg ci -d'2 0' -mc
  $ hg mv b a
  $ hg ci -d'3 0' -md
  $ echo a >> a
  $ hg ci -d'4 0' -me
  $ cd ..
  $ hg convert a 2>&1 | grep -v 'subversion python bindings could not be loaded'
  assuming destination a-hg
  initializing destination a-hg repository
  scanning source...
  sorting...
  converting...
  4 a
  3 b
  2 c
  1 d
  0 e
  $ hg --cwd a-hg pull ../a
  pulling from ../a
  searching for changes
  no changes found
  5 local changesets published

conversion to existing file should fail

  $ touch bogusfile
  $ hg convert a bogusfile
  initializing destination bogusfile repository
  abort: cannot create new bundle repository
  [255]

#if unix-permissions no-root

conversion to dir without permissions should fail

  $ mkdir bogusdir
  $ chmod 000 bogusdir

  $ hg convert a bogusdir
  abort: Permission denied: *bogusdir* (glob)
  [255]

user permissions should succeed

  $ chmod 700 bogusdir
  $ hg convert a bogusdir
  initializing destination bogusdir repository
  scanning source...
  sorting...
  converting...
  4 a
  3 b
  2 c
  1 d
  0 e

#endif

test pre and post conversion actions

  $ echo 'include b' > filemap
  $ hg convert --debug --filemap filemap a partialb | \
  >     grep 'run hg'
  run hg source pre-conversion action
  run hg sink pre-conversion action
  run hg sink post-conversion action
  run hg source post-conversion action

converting empty dir should fail "nicely

  $ mkdir emptydir

override $PATH to ensure p4 not visible; use $PYTHON in case we're
running from a devel copy, not a temp installation

  $ PATH="$BINDIR" "$PYTHON" "$BINDIR"/hg convert emptydir
  assuming destination emptydir-hg
  initializing destination emptydir-hg repository
  emptydir does not look like a CVS checkout
  $TESTTMP/emptydir does not look like a Git repository
  emptydir does not look like a Subversion repository
  emptydir is not a local Mercurial repository
  emptydir does not look like a darcs repository
  emptydir does not look like a monotone repository
  emptydir does not look like a GNU Arch repository
  emptydir does not look like a Bazaar repository
  cannot find required "p4" tool
  abort: emptydir: missing or unsupported repository
  [255]

convert with imaginary source type

  $ hg convert --source-type foo a a-foo
  initializing destination a-foo repository
  abort: foo: invalid source repository type
  [255]

convert with imaginary sink type

  $ hg convert --dest-type foo a a-foo
  abort: foo: invalid destination repository type
  [255]

testing: convert must not produce duplicate entries in fncache

  $ hg convert a b
  initializing destination b repository
  scanning source...
  sorting...
  converting...
  4 a
  3 b
  2 c
  1 d
  0 e

contents of fncache file:

#if repofncache
  $ cat b/.hg/store/fncache | sort
  data/a.i (reporevlogstore !)
  data/b.i (reporevlogstore !)
#endif

test bogus URL

#if no-msys
  $ hg convert -q bzr+ssh://[e-mail]/baz baz
  abort: bzr+ssh://[e-mail]/baz: missing or unsupported repository
  [255]
#endif

test revset converted() lookup

  $ hg --config convert.hg.saverev=True convert a c
  initializing destination c repository
  scanning source...
  sorting...
  converting...
  4 a
  3 b
  2 c
  1 d
  0 e
  $ echo f > c/f
  $ hg -R c ci -d'0 0' -Amf
  adding f
  created new head
  $ hg -R c log -r "converted(09d945a62ce6)"
  changeset:   1:98c3dd46a874
  user:        test
  date:        Thu Jan 01 00:00:01 1970 +0000
  summary:     b
  
  $ hg -R c log -r "converted()"
  changeset:   0:31ed57b2037c
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     a
  
  changeset:   1:98c3dd46a874
  user:        test
  date:        Thu Jan 01 00:00:01 1970 +0000
  summary:     b
  
  changeset:   2:3b9ca06ef716
  user:        test
  date:        Thu Jan 01 00:00:02 1970 +0000
  summary:     c
  
  changeset:   3:4e0debd37cf2
  user:        test
  date:        Thu Jan 01 00:00:03 1970 +0000
  summary:     d
  
  changeset:   4:9de3bc9349c5
  user:        test
  date:        Thu Jan 01 00:00:04 1970 +0000
  summary:     e
  

test specifying a sourcename
  $ echo g > a/g
  $ hg -R a ci -d'0 0' -Amg
  adding g
  $ hg --config convert.hg.sourcename=mysource --config convert.hg.saverev=True convert a c
  scanning source...
  sorting...
  converting...
  0 g
  $ hg -R c log -r tip --template '{extras % "{extra}\n"}'
  branch=default
  convert_revision=a3bc6100aa8ec03e00aaf271f1f50046fb432072
  convert_source=mysource

  $ cat > branchmap.txt << EOF
  > old branch new_branch
  > EOF

  $ hg -R a branch -q 'old branch'
  $ echo gg > a/g
  $ hg -R a ci -m 'branch name with spaces'
  $ hg convert --branchmap branchmap.txt a d
  initializing destination d repository
  scanning source...
  sorting...
  converting...
  6 a
  5 b
  4 c
  3 d
  2 e
  1 g
  0 branch name with spaces

  $ hg -R a branches
  old branch                     6:a24a66ade009
  default                        5:a3bc6100aa8e (inactive)
  $ hg -R d branches
  new_branch                     6:64ed208b732b
  default                        5:a3bc6100aa8e (inactive)