Inconsistent handling of trailing dots can lead to panic

[jonasbb]

// Domain { full: "com", typ: Some(Icann), suffix: Some("com"), registrable: None }
eprintln!("{:?}", list.parse_domain("com").unwrap());
// Domain { full: "localhost", typ: None, suffix: None, registrable: None }
eprintln!("{:?}", list.parse_domain("localhost").unwrap());
// Domain { full: "test.com.", typ: None, suffix: Some("com"), registrable: Some("test.com") }
eprintln!("{:?}", list.parse_domain("test.com.").unwrap());
// Domain { full: "test.localhost.", typ: None, suffix: Some("localhost"), registrable: Some("test.localhost") }
eprintln!("{:?}", list.parse_domain("test.localhost.").unwrap());
// panicked at 'index 2 out of range for slice of length 1'
eprintln!("{:?}", list.parse_domain("com.").unwrap());
// panicked at 'index 2 out of range for slice of length 1'
eprintln!("{:?}", list.parse_domain("localhost.").unwrap());

Notice how the suffix is different for localhost and test.localhost.. I am not sure if this is the same or a different issue.

Stracktrace:

  10: <core::ops::range::Range<usize> as core::slice::SliceIndex<[T]>>::index
             at /checkout/src/libcore/slice/mod.rs:866
  11: <core::ops::range::RangeTo<usize> as core::slice::SliceIndex<[T]>>::index
             at /checkout/src/libcore/slice/mod.rs:912
  12: core::slice::<impl core::ops::index::Index<I> for [T]>::index
             at /checkout/src/libcore/slice/mod.rs:717
  13: <alloc::vec::Vec<T> as core::ops::index::Index<core::ops::range::RangeTo<usize>>>::index
             at /checkout/src/liballoc/vec.rs:1584
  14: publicsuffix::Domain::assemble
             at /cargo/registry/src/github.com-1ecc6299db9ec823/publicsuffix-1.4.0/src/lib.rs:600
  15: publicsuffix::Domain::find_match
             at /cargo/registry/src/github.com-1ecc6299db9ec823/publicsuffix-1.4.0/src/lib.rs:647
  16: publicsuffix::Domain::parse::{{closure}}
             at /cargo/registry/src/github.com-1ecc6299db9ec823/publicsuffix-1.4.0/src/lib.rs:677
  17: <core::result::Result<T, E>>::and_then
             at /checkout/src/libcore/result.rs:602
  18: publicsuffix::Domain::parse
             at /cargo/registry/src/github.com-1ecc6299db9ec823/publicsuffix-1.4.0/src/lib.rs:676
  19: publicsuffix::List::parse_dns_name
             at /cargo/registry/src/github.com-1ecc6299db9ec823/publicsuffix-1.4.0/src/lib.rs:484

Changing lib.rs:671 to

        let input = domain.trim_right_matches('.');

fixes the problem. I will provide a pull request with matching tests later.

[rushmorem]

Thank you for reporting! Will be looking forward to the pull request.

[rushmorem]

Changing lib.rs:671 to

       let input = domain.trim_right_matches('.');

fixes the problem.

Since a valid domain name can only have one trailing ., we must make sure this is the case before calling trim_right_matches otherwise a domain like test.com.. will be parsed as a valid domain name.