[Tcl-bugs] [ tcl-Bugs-3386417 ] errorstack leaked on syntax error

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Bugs item #3386417, was opened at 2011-08-05 01:03
Message generated for change (Comment added) made by ferrieux
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Category: 47. Bytecode Compiler
Group: development: 8.6b2
Status: Open
Resolution: None
Priority: 5
Private: No
Submitted By: miguel sofer (msofer)
>Assigned to: miguel sofer (msofer)
Summary: errorstack leaked on syntax error

Initial Comment:
When the compiler bails out on a syntax error, the errorstack is leaked. For example, for the script

  namespace eval x {set syntax {}{}}

valgrind reports


  0:  malloc (vg_replace_malloc.c:236)
  1:  TclpAlloc (tclAlloc.c:705)
  2:  Tcl_Alloc (tclCkalloc.c:1046)
  3:  Tcl_NewListObj (tclListObj.c:225)
  4:  Tcl_CreateInterp (tclBasic.c:542)
  5:  Tcl_Main (tclMain.c:639)
  6:  main (tclAppInit.c:84)
-- foo: ==9070== 3,248 (48 direct, 3,200 indirect) bytes in 1 blocks are definitely lost in loss record 136 of 136


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>Comment By: Alexandre Ferrieux (ferrieux)
Date: 2011-08-06 12:46

Message:
Quick analysis shows that an extra ref (to errorstack, but also to other
return options) is kept in an options-dict computed by
CompileReturnInternal. That dict is soldered into a literal
(TclAddLiteralObj), so it looks like the lifecycle of that literal is the
culprit.

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