Re: [Boost-bugs] [Boost C++ Libraries] #7630: Range adaptors do not play nicely with range-based for loops

Subject: Re: [Boost-bugs] [Boost C++ Libraries] #7630: Range adaptors do not play nicely with range-based for loops
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2016-06-02 11:33:48

#7630: Range adaptors do not play nicely with range-based for loops
-------------------------------+------------------------
  Reporter:  gromer@…          |      Owner:  neilgroves
      Type:  Bugs              |     Status:  assigned
 Milestone:  To Be Determined  |  Component:  range
   Version:  Boost 1.51.0      |   Severity:  Problem
Resolution:                    |   Keywords:  range
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Comment (by rob.desbois@…):

 What's the current status of this? I have scoured Boost Trac and mailing
 lists recently and still feel uncertain whether the described pattern is
 generally safe. My typical use case is slightly different, though suffers
 from the same potentially-undefined behaviour: functions which return a
 range produced by piping a container through some adaptor chain.

 Looking through the code for some of these adaptors my best understanding
 is that it is safe based on Neil's comment:13 regarding copying of
 underlying iterators. I don't feel comfortable with that though: what if
 the implementation changes?.

 Perhaps while there is no fix (if there still isn't) could a summary of
 the issue and some advice be given in the Boost.Range docs? Even if it
 simply says "Here's the possible issue, but the implementation all of
 Boost's range adaptors means this is never UB" that would suffice: this is
 too concerning an issue regarding a common usage pattern to have no
 official recommendation for IMHO.

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/7630#comment:18>
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