[tor-bugs] #34251 [Core Tor/Tor]: Fix edge case handling in Rust protover is supported

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#34251: Fix edge case handling in Rust protover is supported
-------------------------+-------------------------------------------------
     Reporter:  teor     |      Owner:  (none)
         Type:  defect   |     Status:  new
     Priority:  Medium   |  Milestone:  Tor: 0.4.4.x-final
    Component:  Core     |    Version:  Tor: 0.3.3.5-rc
  Tor/Tor                |   Keywords:  044-should, technical-debt, rust,
     Severity:  Normal   |  protover, 042-backport, 043-backport
Actual Points:  0.1      |  Parent ID:
       Points:  0.5      |   Reviewer:
      Sponsor:           |
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 Tor's Rust FFI for protocol_list_supports_protocol_or_later() returns true
 for the empty protocol list.

 In C, the function returns false, but this behaviour is undocumented.

 This bug doesn't affect protocol_list_supports_protocol() in Rust, because
 the Rust error checks are done in a different order.

 I'll add a quick fix to #33222, but someone else will need to do the
 backport. We might want to do the Rust error checks in the same order,
 too.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/34251>
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