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Item7166: TOC variable has potential infinite recursion

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AppliesTo: Component: Priority: CurrentState: WaitingFor: TargetRelease ReleasedIn
Engine   Normal Closed   major 6.0.0

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Released In:


TWikibug:Item6864 expands variables when handling %TOC%, but this exposes potential infinite recursion possibility.
To reproduce it, just create two pages, "TestPage1" and "TestPage2". These two pages have exactly the same content as
---++ %TOPIC%
---++ %WEB%
Then neither "TestPage1" nor "TestPage2" can be opened until timeout.

I escape TOC variables before TOC handler expands variables again.
$ svn diff TWiki.pm
Index: TWiki.pm
--- TWiki.pm    (revision 25187)
+++ TWiki.pm    (working copy)
@@ -2599,7 +2599,8 @@
         my $meta;
         ( $meta, $text ) = $this->{store}->readTopic( $this->{user}, $web, $topic );
+        # Item7166: Escape %TOC% to avoid infinite recursion.
+        $text =~ s/%(TOC[{%])/%<nop>$1/g;
         # Item6864: 2012-03-29 TWiki:Main.GertjanVanOosten, gertjan at west dot nl:
         #   Handle common tags, as the text may contain variables etc. that need
         #   to be expanded before generating the TOC for another topic.
         $text = $this->handleCommonTags( $text, $web, $topic, $meta );

-- TWiki:Main/YaojunFei - 2013-02-26

This is now fixed differently in Item7286. There was still an infinite loop possible if an INCLUDEd topic had a TOC.

-- TWiki:Main.PeterThoeny - 2013-06-28

Summary TOC variable has potential infinite recursion
ReportedBy TWiki:Main.YaojunFei
Codebase ~twiki4, 5.1.4, 5.1.3, 5.1.2
SVN Range TWiki-5.1.3-trunk, Wed, 20 Feb 2013, build 25123
AppliesTo Engine

Priority Normal
CurrentState Closed

Checkins TWikirev:25206 TWikirev:25211 TWikirev:25236
TargetRelease major
ReleasedIn 6.0.0
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Topic revision: r11 - 2013-10-15 - PeterThoeny
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