Bug: Variables Can't be set to 0

It seems that one can't set a WebPreferences variable to zero ('0'). It always evaluates to the empty string "". There's a fix in the Answer section, below.

Test case

• Create a Set TEST = 0 bullet in WebPreferences

Fix record

TWiki::Prefs::getPrefsFromTopic uses this Perl idiom when it's evaluating preference variable values:

   $value = $2 || "";

The problem is that the assignment will fall through to the empty string ("") whenever $2 is false, which, by Perl's definition of "false", means whenever $2 is undefined, the empty string, or zero (0).

The fix is to check whether or not $2 is defined, since that's the only case for which we really want to force the empty string:

   $value = defined $2 ? $2 : "";

-- TrippLilley - 15 Nov 2001

Fixed, in TWikiAlphaRelease.

Applied same fix for %VARIABLE{name="0"}% in TWiki::extractNameValuePair

-- PeterThoeny - 16 Nov 2001

Environment

-- TrippLilley - 15 Nov 2001