nimforum mirror - Strange memory problem

mantielero (orginal) [2021-02-17T22:54:20+01:00] view original

I am reviewing some code that I did some time ago and has stopped working properlly. The code wraps a C library (vapoursynth).

What is happening is that the code works when run with --d:danger but it fails without it.

The code is pretty simple. In one hand:

import ../src/vapoursynth
discard Source("2sec.mkv").Turn180

The function Turn180 is the one that is producing the failure:

proc Turn180*(vsmap:ptr VSMap):ptr VSMap =
  echo "A: ",vsmap.len("clip")
  let plug = getPluginById("com.vapoursynth.std")
  echo "B: ",vsmap.len("clip")
  #echo repr cast[pointer](vsmap)
  #let args = createMap()
  #args.append("clip", clip)
  assert( plug != nil, "plugin \"com.vapoursynth.std\" not installed properly in your computer")
  echo "C: ",vsmap.len("clip")
  assert( vsmap.len != 0, "the vsmap should contain at least one item")
  echo "D: ",vsmap.len("clip")
  assert( vsmap.len("clip") != 1, "the vsmap should contain one node")
  echo "E: ",vsmap.len("clip")
  var clip = getFirstNode(vsmap)
  
  
  # Convert the function parameters into a VSMap (taking into account that some of them might be optional)
  let args = createMap()
  args.append("clip", clip)
  
  result = API.invoke(plug, "Turn180".cstring, args)
  API.freeMap(args)

When I run it without --d:danger:


$ nim c --threads:on --tlsSimulation:off ex01

$ ./ex01
A: 1
B: 1
C: 1
D: 1
/home/jose/src/VapourSynth.nim/test/ex01.nim(10) ex01
/home/jose/src/VapourSynth.nim/src/plugins/std.nim(1104) Turn180
/home/jose/.choosenim/toolchains/nim-1.4.2/lib/system/assertions.nim(30) failedAssertImpl
/home/jose/.choosenim/toolchains/nim-1.4.2/lib/system/assertions.nim(23) raiseAssert
/home/jose/.choosenim/toolchains/nim-1.4.2/lib/system/fatal.nim(49) sysFatal
Error: unhandled exception: /home/jose/src/VapourSynth.nim/src/plugins/std.nim(1104, 9) `vsmap.len("clip") != 1` the vsmap should contain one node [AssertionDefect]

so I don't know how can I get D: 1 and then failing in the next assertion.

Any idea about what might be going on?

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7524 :: Strange memory problem