filemerge: add config knob to check capabilities of internal merge tools
For historical reason, Mercurial assumes capabilities of internal
merge tools as below while examining rules to decide merge tool,
regardless of actual capabilities of them.
=============== ====== ========
specified via binary symlinks
=============== ====== ========
--tool o o
HGMERGE o o
merge-patterns o (*) x (*)
ui.merge x (*) x (*)
=============== ====== ========
This causes:
- unintentional internal merge tool is chosen for binary files via
merge-patterns section of configuration file
- explicit configuration of internal merge tool for symlinks is
ignored unintentionally
But on the other hand, simple "check capability strictly" might break
backward compatibility (e.g. existing merge automations), because it
changes the result of merge tool selection.
Therefore, this patch adds config knob "merge.strict-capability-check"
to control whether capabilities of internal merge tools should be
checked strictly or not.
If this configuration is true, capabilities of internal merge tools
are checked strictly in (*) cases above.
Mercurial's documentation is kept in reStructuredText format, which is
a simple plain text format that's easy to read and edit:
http://docutils.sourceforge.net/rst.html
It's also convertible to a variety of other formats including standard
UNIX man page format and HTML. You'll need to install Docutils:
http://docutils.sourceforge.net/
Use the Makefile in this directory to generate the man and HTML pages.