diff: add a --noprefix option See previous patch descriptions for the motivation. The tests reflect the current state of the world -- as we add support we'll see changes in the test output.

patch.diffopts: add support for noprefix In an upcoming patch we'll enable support as an option to 'hg diff' as well. The tests reflect the current state of the world -- as we add support we'll see changes in the test output.

patch.diffopts: allow a setting to be forced in plain mode Upcoming patches will add an option that will almost certainly break diff output parsers when enabled. Add support for forcing an option to something in plain mode, as a fallback. Options passed in via the CLI are not affected, though -- it is assumed that any script passing the option in explicitly knows what it is doing.

patch.diffopts: break get function into if statements We're going to add another condition here, and with the current structure that becomes just too confusing.

mdiff.diffopts: add a new noprefix option By popular demand, we introduce an option to disable the 'a/' and 'b/' prefixes in diff output. This makes copying and pasting filenames from diff output easier. This option will be implemented and documented in upcoming patches. To ensure that existing scripts that parse output don't break, we will ensure that this prefix is disabled in plain mode. A straight 'hg export | hg import' without HGPLAIN=1 will still be broken though, but there's little that can be done about that.

mdiff.diffopts: add doc comment for nobinary