[MacPorts] #60564: Make setting known_fail yes also prevent looking for archives

[MacPorts]

#60564: Make setting known_fail yes also prevent looking for archives
--------------------------+-----------------------------
  Reporter:  ryandesign   |      Owner:  (none)
      Type:  enhancement  |     Status:  new
  Priority:  Normal       |  Milestone:  MacPorts Future
 Component:  base         |    Version:  2.6.2
Resolution:               |   Keywords:
      Port:               |
--------------------------+-----------------------------
Description changed by ryandesign:

Old description:

> Some ports do this (this is from gcc49):
>
> {{{
> if {${os.platform} eq "darwin" && ([vercmp $xcodeversion 9.0] > 0)} {
>     known_fail      yes
>     depends_lib
>     depends_run
>     archive_sites
>     pre-fetch {
>         ui_error "building ${name} is not supported with Xcode 9 or
> greater"
>         return -code error {unsupported platform}
>     }
> }
> }}}
>
> In other words in addition to setting `known_fail yes` and printing an
> error message, it clears `archive_sites`. This is probably intended to
> stop MacPorts from spending time checking for an archive that we already
> know does not exist. Maybe MacPorts base could arrange for
> `archive_sites` to be cleared automatically when `known_fail yes` is
> used, or it could use some other method to prevent checking for the
> presence of archives.
>
> I'll file a separate ticket about clearing dependencies.

New description:

 Some ports do this (this is from gcc49):

 {{{
 if {${os.platform} eq "darwin" && ([vercmp $xcodeversion 9.0] > 0)} {
     known_fail      yes
     depends_lib
     depends_run
     archive_sites
     pre-fetch {
         ui_error "building ${name} is not supported with Xcode 9 or
 greater"
         return -code error {unsupported platform}
     }
 }
 }}}

 In other words in addition to setting `known_fail yes` and printing an
 error message, it clears `archive_sites`. This is probably intended to
 stop MacPorts from spending time checking for an archive that we already
 know does not exist. Maybe MacPorts base could arrange for `archive_sites`
 to be cleared automatically when `known_fail yes` is used, or it could use
 some other method to prevent checking for the presence of archives.

 A [ticket:60565 separate ticket] tracks clearing dependencies.

--

-- 
Ticket URL: <https://trac.macports.org/ticket/60564#comment:1>
MacPorts <https://www.macports.org/>
Ports system for macOS