[MacPorts] #64353: opencv3 has undocumented dependencies

[MacPorts]

#64353: opencv3 has undocumented dependencies
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  Reporter:  mouse07410  |      Owner:  mascguy
      Type:  defect      |     Status:  assigned
  Priority:  Normal      |  Milestone:
 Component:  ports       |    Version:
Resolution:              |   Keywords:
      Port:  opencv3     |
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Comment (by mouse07410):

 Could you please help me understand what I'm missing? I'm trying to figure
 the logic of {{{default_compilers}}} behavior. 1860-lines-worth TCL script
 did not help me - last time I touched TCL was around 2003, and I does not
 seem to deal with {{{default_compilers}}} anyway.

 I thought that:
 - {{{default_compilers}}} provides a **list** of compilers to try, in
 order of preference.
 - Entries from this list are checked until a fit is found, or the list is
 exhausted;
 - "Fit" above means the compiler from the list entry satisfies all of the
 port constraints.

 Why when {{{opencv3}}} port is evaluated, if {{{macports-clang-13} is
 listed first, it is picked and listed, but if it's listed second - it is
 not listed in the "deps"?

 > {{{default_compilers}}} is picking the first default compiler you
 specified

 In that case, why is it named "compiler**s**", and contains more than one
 entry? When the first default compiler does not satisfy the "openmp"
 constraint - why does t "it" (whatever "it" means in the context) proceed
 to the **next** entry???

-- 
Ticket URL: <https://trac.macports.org/ticket/64353#comment:38>
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