[MacPorts] #55653: "sudo port upgrade outdated" fails

[MacPorts]

#55653: "sudo port upgrade outdated" fails
--------------------+-----------------
 Reporter:  jhi     |      Owner:
     Type:  defect  |     Status:  new
 Priority:  Normal  |  Milestone:
Component:  ports   |    Version:
 Keywords:          |       Port:
--------------------+-----------------
 {{{
 $ sudo port upgrade outdated
 Error: Follow https://guide.macports.org/#project.tickets to report a bug.
 $
 }}}

 And ... that's it.

 According to "selfupdate" I'm not completely broken.

 {{{

 $ sudo port selfupdate
 Password:
 --->  Updating MacPorts base sources using rsync
 MacPorts base version 2.4.2 installed,
 MacPorts base version 2.4.2 downloaded.
 --->  Updating the ports tree
 --->  MacPorts base is already the latest version

 The ports tree has been updated. To upgrade your installed ports, you
 should run
   port upgrade outdated
 }}}

 OS:

 {{{
 $ sw_vers
 ProductName:    Mac OS X
 ProductVersion: 10.13.2
 BuildVersion:   17C88
 }}}

--
Ticket URL: <https://trac.macports.org/ticket/55653>
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