Detect when user supplied path instead of pattern

[sharkdp]

From time to time it happens to me that I forget to supply a regex-pattern when using an explicit search path. In particular, this happens when I use --extension EXT/-e EXT because it feels like EXT is a pattern by itself:

> fd -e jpg /share/pictures    # this will not do what you expect

The right way would be to use fd -e jpg . /share/pictures or fd -e jpg "" /share/pictures.

Instead, what the command above will try to do is to search for files in the current directory that match the regular expression /share/pictures (there will be none). I was wondering whether we could detect such cases and warn the user.

A possible implementation could look like this:

If all of the following conditions are fulfilled:

• only a single argument is given (which fd normally interprets as a search pattern)
• the pattern contains a path-separation character (/ or \)
• (the pattern is an existing path in the filesystem)
• --full-path/-p has not been enabled (otherwise, we could potentially find entries that match the pattern)

... print a warning:

The search pattern "/share/pictures" looks like a path. If you want to specify a
root directory, use an empty search pattern: `fd [options] "" /share/pictures`.

[sharkdp]

In addition, we could also suggest --full-path/-p if somebody really wants to search for a part of a path.

[sharkdp]

Released as part of fd v7.0.0