This is still a very naive implementation and there are plenty of other
cases that we should handle (like a quoted path) - but just looking for
a tab handles the common case.
We should still add an informational message about when this happens
before we even get here - but we still shouldn't be able to locate a
place to apply a hunk as it ends up producing unexpected results where
the patch is prepended to the existing file.
It's not always important to verify what the contents of stdout are when
adding a patch test - especially if it's not exactly what we want it to
be, so make this optional when running patch for a test.
Multiple patches may be concatenated in the same patch file, such as git
commits which are changing multiple files at the same time. To handle
this, parse each patch in order in the patch file, and apply each patch
sequentially.
To determine whether we are at the end of a patch (and not just parsing
another hunk) the parser will look for a leading '@@ ' after every hunk.
If that is found, there is another hunk. Otherwise, we must be at the
end of this patch.
Previously patch would always expect the file that it was patching to
exist (even it were empty). If we know that the patch is creating a file
from nothing (i.e has a start line of '0'), then we treat a file that
doesn't exist as if it has no content lines.
Implement the patch '-p' / '--strip' option, which strips the given
number of leading components from filenames parsed in the patch header.
If not given this option defaults to the basename of that path.
