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4981 :: Passing openArray[(string,string)] to async proc, then to encodeQuery

• Softgate (orginal) [2019-06-30T10:45:43+02:00] view original

  I found that, in the code below, myEncodeQuery works well while myAsyncEncodeQuery isn't even compiled.

  import uri, asyncdispatch
  
  proc myAsyncEncodeQuery(query: openArray[(string, string)]) {.async.} =
    echo(encodeQuery(query))
  
  proc myEncodeQuery(query: openArray[(string, string)]) =
    echo(encodeQuery(query))
  
  echo(encodeQuery({"foo": "bar", "baz": "qux"}))
  
  myEncodeQuery({"foo": "bar", "baz": "qux"})
  
  # commenting the line below will eliminate the compile error.
  waitFor myAsyncEncodeQuery({"foo": "bar", "baz": "qux"})
  Run

  I got a compilation error something like:

  
  Error: 'query' is of type <openarray[tuple of (string, string)]> which cannot be captured as it would violate memory safety, declared here: D:\...\test.nim(3, 25)
  Run

  What kind of memory safety violation it is causing, and is there any way to avoid the error?

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• Araq (orginal) [2019-06-30T14:54:52+02:00] view original

  Workaround: Use seq[(string, string)] as the parameter type.

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