SocketUtils does not properly detect available port on localhost [SPR-13321]

[spring-projects-issues]

Gary Russell opened SPR-13321 and commented

Status Quo

SocketUtils attempts to find an unused socket.

This does not work (at least on OS X) if something is already bound to localhost but not to other network interfaces. Instead, the requested socket is successfully bound to other network interfaces.

Proposal

Since tests generally want to bind to localhost, SocketUtils should test the loopback interface to ensure that the port is actually available for localhost.

Further Resources

See pull request 1537 for a similar fix in Spring Integration.

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Affects: 4.0 GA

Referenced from: pull request #853, and commits f151404

[spring-projects-issues]

Sam Brannen commented

Fixed in GitHub commit f151404:

Properly detect available port on localhost in SocketUtils

SocketUtils is used to find available ports on localhost; however, prior to this commit, SocketUtils incorrectly reported a port as available on localhost if another process was already bound to localhost on the given port but not to other network interfaces. In other words, SocketUtils determined that a given port was available for some interface though not necessarily for the loopback interface.

This commit addresses this issue by refactoring SocketUtils so that it tests the loopback interface to ensure that the port is actually available for localhost.