== Description ==

[[http://meldmerge.org/|Meld]] is a tool for making manual merges. It is a 3-way editor with visualization and propagation of differences.

Meld is available for Linux, MacOS, and Windows. On MacOS, Meld is available from [[https://www.macports.org/|MacPorts]], Fink, and [[https://brew.sh/|Homebrew]]. There are some notes available on [[https://wiki.gnome.org/Apps/Meld/Windows|how to get Meld running on Windows]].

== Usage notes and tips ==

 * "Arrows" for propagation mode are toggled somehow with shift and control and alt
 * All 3 panes can be edited individually and must be saved individually
 * One way of working with Meld is to work towards making all 3 files equal - that forces you to review and rethink your merges in both contexts
 * Mercurial by default puts "file" is to the left, then "file~base", and finally "file~other"
 * By default then the left pane is the merge result
 * Enjoy that it is easy to see how the base version has diverged into two different versions
 * Changes from the new parent in "file~other" (to the right) can be propagated to "file" (to the left) through "file~base"
 * You could (and should?) start by copying everything from "file~other" to "file~base" in order to work with the two parents side-by-side - but then it is just a two-way merge...
 * Or, to change the order and which panes are displayed add a section "[merge-tools]" with "meld.args = $base $local $other" to your ~/.hgrc, specifying the order you prefer (since Meld's default order is different from some other diff tools)
 * To not see base at all set it to "meld.args = $local $other". You merge to the local copy, which in this arrangement is still the left pane

== Example .hgrc config ==
{{{
[merge-tools]
meld.priority = 1
meld.args = $base $local $other
}}}

== Using meld for viewing diffs ==
Adding this to your {{{.hgrc}}} will give you a {{{hg meldiff}}} command to view diffs in Meld (of course you can call it what you like).
{{{
[extensions]
hgext.extdiff=

[extdiff]
cmd.meldiff = meld
}}}