Shell no longer accepts legacy connection strings

The MongoDB 3.4.11 shell broke the "legacy" style host[:port]/dbname connection string format.

3.4.11

$ mongo localhost/admin

MongoDB shell version v3.4.11

connecting to: mongodb://admin:27017/localhost

2018-02-01T14:16:28.467-0600 I NETWORK  [thread1] getaddrinfo("admin") failed: nodename nor servname provided, or not known

2018-02-01T14:16:28.467-0600 E QUERY    [thread1] Error: couldn't initialize connection to host admin, address is invalid :

connect@src/mongo/shell/mongo.js:240:13

@(connect):1:6

exception: connect failed

There are two workarounds for this issue:

• Use a 3.4.10 shell:

  $ mongo localhost/admin

  MongoDB shell version v3.4.10

  connecting to: mongodb://localhost/admin

  MongoDB server version: 3.4.11

  >

• Use the --host <host> <database> syntax:

  $ mongo --host localhost admin

  MongoDB shell version v3.4.11

  connecting to: mongodb://localhost:27017/admin

  MongoDB server version: 3.4.11

  >

The documentation and --help parameters both show this as a valid connection string.

mongo --help

MongoDB shell version v3.4.11

usage: mongo [options] [db address] [file names (ending in .js)]

db address can be:

  foo                   foo database on local machine

  192.168.0.5/foo       foo database on 192.168.0.5 machine