tests/test-convert-authormap.t

log: add -L/--line-range option to follow file history by line range

We add an experimental -L/--line-range option to 'hg log' taking file patterns
along with a line range using the (new) FILE,FROMLINE-TOLINE syntax where FILE
may be a pattern (matching exactly one file). The resulting history is similar
to what the "followlines" revset except that, if --patch is specified,
only diff hunks within specified line range are shown.

Basically, this brings the CLI on par with what currently only exists in hgweb
through line selection in "file" and "annotate" views resulting in a file log
with filtered patch to only display followed line range.

The option may be specified multiple times and can be combined with --rev and
regular file patterns to further restrict revisions. Usage of this option
requires --follow; revisions are shown in descending order and renames are
followed. Only the --graph option is currently not supported.

The UI is the result of a consensus from review feedback at:

  https://www.mercurial-scm.org/pipermail/mercurial-devel/2017-October/106749.html


The implementation spreads between commands.log() and cmdutil module.
In commands.log(), the main loop may now use a "hunksfilter" factory (similar
to "filematcher") that, for a given "rev", produces a filtering function
for diff hunks for a given file context object.
The logic to build revisions from -L/--line-range options lives in
cmdutil.getloglinerangerevs() which produces "revs", "filematcher" and
"hunksfilter" information. Revisions obtained by following files' line range
are filtered if they do not match the revset specified by --rev option. If
regular FILE arguments are passed along with -L options, both filematchers are
combined into a new matcher.

.. feature::

   Add an experimental -L/--line-range FILE,FROMLINE-TOLINE option to 'hg log'
   command to follow the history of files by line range. In combination with
   -p/--patch option, only diff hunks within specified line range will be
   displayed. Feedback, especially on UX aspects, is welcome.

  $ cat >> $HGRCPATH <<EOF
  > [extensions]
  > convert=
  > EOF

Prepare orig repo

  $ hg init orig
  $ cd orig
  $ echo foo > foo
  $ HGUSER='user name' hg ci -qAm 'foo'
  $ cd ..

Explicit --authors

  $ cat > authormap.txt <<EOF
  > user name = Long User Name
  > 
  > # comment
  > this line is ignored
  > EOF
  $ hg convert --authors authormap.txt orig new
  initializing destination new repository
  ignoring bad line in author map file authormap.txt: this line is ignored
  scanning source...
  sorting...
  converting...
  0 foo
  writing author map file $TESTTMP/new/.hg/authormap (glob)
  $ cat new/.hg/authormap
  user name=Long User Name
  $ hg -Rnew log
  changeset:   0:d89716e88087
  tag:         tip
  user:        Long User Name
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     foo
  
  $ rm -rf new

Implicit .hg/authormap

  $ hg init new
  $ mv authormap.txt new/.hg/authormap
  $ hg convert orig new
  ignoring bad line in author map file $TESTTMP/new/.hg/authormap: this line is ignored (glob)
  scanning source...
  sorting...
  converting...
  0 foo
  $ hg -Rnew log
  changeset:   0:d89716e88087
  tag:         tip
  user:        Long User Name
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     foo