tests/test-manifest-merging.t

color: turn 'ui.color' into a boolean (auto or off)

Previously, 'ui.color=yes' meant "always show color", While
"ui.color=auto" meant "use color automatically when it appears
sensible".

This feels problematic to some people because if an administrator has
disabled color with "ui.color=off", and a user turn it back  on using
"color=on", it will get surprised (because it breaks their output when
redirected to a file.) This patch changes ui.color=true to only move the
default value of --color from "never" to "auto".

I'm not really in favor of this changes as I suspect the above case will
be pretty rare and I would rather keep the logic simpler. However, I'm
providing this patch to help the 4.2 release in the case were others
decide to make this changes.

Users that want to force colors without specifying --color on the
command line can use the 'ui.formatted' config knob, which had to be
enabled in a handful of tests for this patch.

Nice summary table (credit: Augie Fackler)

That is, before this patch:

+--------------------+--------------------+--------------------+
|                    | not a tty          | a tty              |
|                    | --color not set    | --color not set    |
|                    |                    |                    |
+--------------------+--------------------+--------------------+
| [ui]               |                    |                    |
| color (not set)    | no color           | no color           |
|                    |                    |                    |
+--------------------+--------------------+--------------------+
| [ui]               |                    |                    |
| color = auto       | no color           | color              |
|                    |                    |                    |
+--------------------+--------------------+--------------------+
| [ui]               |                    |                    |
| color = yes        | *color*            | color              |
|                    |                    |                    |
+--------------------+--------------------+--------------------+
| [ui]               |                    |                    |
| color = no         | no color           | no color           |
|                    |                    |                    |
+--------------------+--------------------+--------------------+
(if --color is specified, it always clobbers the setting in [ui])

and after this patch:

+--------------------+--------------------+--------------------+
|                    | not a tty          | a tty              |
|                    | --color not set    | --color not set    |
|                    |                    |                    |
+--------------------+--------------------+--------------------+
| [ui]               |                    |                    |
| color (not set)    | no color           | no color           |
|                    |                    |                    |
+--------------------+--------------------+--------------------+
| [ui]               |                    |                    |
| color = auto       | no color           | color              |
|                    |                    |                    |
+--------------------+--------------------+--------------------+
| [ui]               |                    |                    |
| color = yes        | *no color*         | color              |
|                    |                    |                    |
+--------------------+--------------------+--------------------+
| [ui]               |                    |                    |
| color = no         | no color           | no color           |
|                    |                    |                    |
+--------------------+--------------------+--------------------+
(if --color is specified, it always clobbers the setting in [ui])

  $ hg init base

  $ cd base
  $ echo 'alpha' > alpha
  $ hg ci -A -m 'add alpha'
  adding alpha
  $ cd ..

  $ hg clone base work
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

  $ cd work
  $ echo 'beta' > beta
  $ hg ci -A -m 'add beta'
  adding beta
  $ cd ..

  $ cd base
  $ echo 'gamma' > gamma
  $ hg ci -A -m 'add gamma'
  adding gamma
  $ cd ..

  $ cd work
  $ hg pull -q
  $ hg merge
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)

Update --clean to revision 1 to simulate a failed merge:

  $ rm alpha beta gamma
  $ hg update --clean 1
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved

  $ cd ..