[MacPorts] #48562: Update qwt to 6.1.2

[MacPorts]

#48562: Update qwt to 6.1.2
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  Reporter:  ghweber@…  |      Owner:  macports-tickets@…
      Type:  update     |     Status:  new
  Priority:  Normal     |  Milestone:
 Component:  ports      |    Version:  2.3.3
Resolution:             |   Keywords:  haspatch
      Port:  qwt        |
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Comment (by ghweber@…):

 Replying to [comment:1 ryandesign@…]:
 > Replying to [ticket:48562 ghweber@…]:
 > > The attached Portfile adds a qwt61 variant (replacing the qwt-devel
 variant that installs an outdated release 6.1 release candidate), which
 installs the current Qwt 6.1.2
 >
 > You mean subport, not variant.
 Yes, I did.
 >
 > > - I am not sure if I need to add something to ensure that existing
 installations of qwt-devel get upgraded to qwt61.
 >
 > Yes, you do: you need to retain a qwt-devel subport, which contains the
 line `replaced_by qwt61`. The version or revision of qwt-devel also needs
 to be increased to cause the replacement to occur. See
 https://guide.macports.org/chunked/development.practices.html#development.practices
 .rename-replace-port

 I tried to modify the Portfile accordingly. However, I cannot figure out
 how to make this work properly with subports. I am attaching a diff and
 the Portfile for my attempt. When I try to install qwt-develp, it still
 tries to download the distfiles (even though I have an empty distfiles
 line as indicated in the instruction) and does not print the error message
 listed in pre-configure.

 How do I make this work with a subport?

 Gunther

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Ticket URL: <https://trac.macports.org/ticket/48562#comment:2>
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