tests/test-branch-tag-confict.t

log: add a "graphwidth" template variable

Wrapping text in templates for 'hg log --graph' can't be done very well,
because the template doesn't know how wide the graph drawing is. The edge
drawing function needs to know the number of lines in the template output, so
we need to also determine how wide that drawing would be before we call the
edgefn or evaluate the template.

This patch makes edgefn compute the graph width and pass it into the template
so that we can do something like this:

COLUMNS=10 hg log --graph --template "{fill(desc, termwidth - graphwidth)}"
@  a a a a
|  a a a a
|  a a a a
o    a a a
|\   a a a
| |  a a a
| |  a a a

Using extensions to do this would be relatively complicated due to a lack of
hooks in this area of the code.

In the future it may make sense to have a more generic "textwidth" that tells
you how many columns you can expect to fill without causing the terminal to
wrap your output. I'm not sure there are other situations to motivate this yet,
or if it is entirely feasible.

Differential Revision: https://phab.mercurial-scm.org/D360

Initial setup.

  $ hg init repo
  $ cd repo
  $ touch thefile
  $ hg ci -A -m 'Initial commit.'
  adding thefile

Create a tag.

  $ hg tag branchortag

Create a branch with the same name as the tag.

  $ hg branch branchortag
  marked working directory as branch branchortag
  (branches are permanent and global, did you want a bookmark?)
  $ hg ci -m 'Create a branch with the same name as a tag.'

This is what we have:

  $ hg log
  changeset:   2:10519b3f489a
  branch:      branchortag
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     Create a branch with the same name as a tag.
  
  changeset:   1:2635c45ca99b
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     Added tag branchortag for changeset f57387372b5d
  
  changeset:   0:f57387372b5d
  tag:         branchortag
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     Initial commit.
  
Update to the tag:

  $ hg up 'tag(branchortag)'
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ hg parents
  changeset:   0:f57387372b5d
  tag:         branchortag
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     Initial commit.
  
Updating to the branch:

  $ hg up 'branch(branchortag)'
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg parents
  changeset:   2:10519b3f489a
  branch:      branchortag
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     Create a branch with the same name as a tag.
  

  $ cd ..