source: downloads/tcl8.5.2/tests/stack.test @ 45

# Tests that the stack size is big enough for the application.
#
# This file contains a collection of tests for one or more of the Tcl
# built-in commands.  Sourcing this file into Tcl runs the tests and
# generates output for errors.  No output means no errors were found.
#
# Copyright (c) 1998-2000 Ajuba Solutions.
#
# See the file "license.terms" for information on usage and redistribution
# of this file, and for a DISCLAIMER OF ALL WARRANTIES.
#
# RCS: @(#) $Id: stack.test,v 1.22 2007/12/13 15:26:07 dgp Exp $

if {[lsearch [namespace children] ::tcltest] == -1} {
    package require tcltest 2
    namespace import -force ::tcltest::*
}

# Note that a failure in this test results in a crash of the executable.
# In order to avoid that, we do a basic check of the current stacksize.
# This size can be changed with ulimit (ksh/bash/sh) or limit (csh/tcsh).

# This doesn't catch all cases, for example threads of lower stacksize
# can still squeak through.  A core check is really needed. -- JH

testConstraint minStack2400 1
if {[testConstraint unix]} {
    set stackSize [exec /bin/sh -c "ulimit -s"]
    if {[string is integer $stackSize] && ($stackSize < 2400)} {
        puts stderr "WARNING: the default application stacksize of $stackSize\
                may cause Tcl to\ncrash due to stack overflow before the\
                recursion limit is reached.\nA minimum stacksize of 2400\
                kbytes is recommended.\nSkipping infinite recursion test."
        testConstraint minStack2400 0
    }
}

#
# Custom match to detect a stack overflow independently of the mechanism that
# triggered the error.
#

customMatch stackOverflow StackOverflow
proc StackOverflow {- res} {
    set msgList [list \
            "too many nested evaluations (infinite loop?)"\
            "out of stack space (infinite loop?)"]
    expr {$res in $msgList}
}

test stack-1.1 {maxNestingDepth reached on infinite recursion} -constraints {
    minStack2400
} -body {
    # do this in a sub process in case it segfaults
    exec [interpreter] << {
        proc recurse {} { recurse }
        catch { recurse } rv
        puts $rv
    }
} -match stackOverflow

test stack-2.1 {maxNestingDepth reached on infinite recursion} -constraints {
    minStack2400
} -body {
    # do this in a sub process in case it segfaults
    exec [interpreter] << {
        interp alias {} unknown {} notaknownproc
        catch { unknown } msg
        puts $msg
    }
} -match stackOverflow 
    
# Make sure that there is enough stack to run regexp even if we're
# close to the recursion limit. [Bug 947070] [Patch 746378]
test stack-3.1 {enough room for regexp near recursion limit} -body {
    # do this in a sub process in case it segfaults
    exec [interpreter] << {
        interp recursionlimit {} 10000
        set depth 0
        proc a { max } {
            if { [info level] < $max } {
                set ::depth [info level]
                a $max
            } else {
                regexp {^ ?} x
            }
        }
        catch { a 10001 }
        set depth2 $depth
        puts [list [a $depth] [expr { $depth2 - $depth }]]
    }
} -result {1 1}

# cleanup
::tcltest::cleanupTests
return

# Local Variables:
# mode: tcl
# End: