extdiff: allow a preconfigured merge-tool to be invoked
There are three ways to configure an extdiff tool:
1) cmd.tool = (/path/to/exe optional)
2) tool = (path/to/exe optional)
3) tool = sometool someargs
Previously, if no executable is specified in the first two forms, the named tool
must be in $PATH, or the invocation fails. Since the [merge-tools] section
already has the path to the diff executable, and/or the registry keys to find
the executable on Windows, reuse that configuration for forms 1 and 2 instead of
failing. We already fallback to [diff-tools] and then [merge-tools] for program
arguments if they aren't specified in the [extdiff] section.
Since this additional lookup only occurs if an executable is not on the $PATH
for the named tool, this is backwards compatible. For now, we assume the user
knows what he is doing if a path is provided.
This change allows a configuration file like this (assuming beyondcompare3 is
configured in merge-tools), instead of hardcoding system specific a path:
[extdiff]
beyondcompare3 =
$ hg init
$ echo a > a
$ hg ci -qAm 'add a'
$ echo b > b
$ hg ci -qAm 'add b'
$ hg up -qC 0
$ hg rm a
$ hg ci -m 'rm a'
created new head
$ hg up -qC 1
$ rm a
Local deleted a file, remote removed
Should fail, since there are deleted files:
$ hg merge
abort: uncommitted changes
(use 'hg status' to list changes)
[255]
Should succeed with --force:
$ hg -v merge --force
resolving manifests
removing a
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
(branch merge, don't forget to commit)
Should show 'a' as removed:
$ hg status
R a
$ hg ci -m merge
Should not show 'a':
$ hg manifest
b