#7 (316) wasn't a bug. When someone constructs a mvim: URL, they should end up escaping the unsafe characters in the path twice: once for the file: URL (e.g. file://Users/steve/foo%20bar/baz.txt) and again for the mvim: URL.

Escaping the whole thing inside MacVim, like this fix did, breaks legit URLs. Here's an example in Python:

import urllib, webbrowser
url = "mvim://open?" + urllib.urlencode({
    "url": "file://" + urllib.pathname2url('/Users/steve/foo bar/baz.txt')
})
print(url) # -> mvim://open?url=file%3A%2F%2F%2FUsers%2Fsidney%2Ffoo%2520bar%2Fbaz.txt
webbrowser.open(url) # Should work, currently fails

In ObjC, the slashes and colon aren't escaped (equally valid as what Python does) but the space does get correctly double-escaped, so same breakage:

NSLog(@"mvim://open?url=%@", [
    [[NSURL fileURLWithPath:@"/Users/sidney/foo bar/baz.txt"] absoluteString]
    stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding
]); // -> mvim://open?url=file://localhost/Users/sidney/foo%2520bar/baz.txt