Item11188: Internal Server Error on DBCALL

Latest Version (2.00) of SetVariablePlugin causes certain DBCALL calls to fail with an internal Server Error:

"$percntDBCALL{\"$2.$3->RenderIndexItem\"}$percnt"

A Rollback to Version 1.02 solved the Problem.

-- OliverSchaub - 20 Oct 2011

Could you please provide a bit more info to this bug report?

-- MichaelDaum - 20 Oct 2011

We have a Topic with the following Code:

%MAKEINDEX{
  "%DBQUERY{
    order="modified"
    reverse="on"
    limit="14"
    exclude="^(WebChanges|WebPreferences|WebTopicLinks|WebIndex|WebNotify|WebHome|WebTagCloud|WebLinks)"
    format="$expand(topWictitle);$web;$topic$n"
  }%"
  pattern="(.*);(.*);(.*)"
  split="\n"
  format="$percntD BCALL{\"$2.$3->RenderIndexItem\"}$percnt"
  group=""
  cols="2"
  sort="off"
}%

(I had to put a "space" here in DBCALL otherwise it gets executed even inside verbatim...)

If you save this Topic you'll get an Internal Server Error. Output from the Logfile:

FastCGI: server "/path/to/wiki/bin/foswiki.fcgi" stderr: Can't call method "fastget" on an undefined value at /path/to/wiki/lib/Foswiki/Plugins/DBCachePlugin/Core.pm line 477., referer: https://our.server.ch/foswiki113x/bin/edit/NameOfTheWeb/WebHomeCopy?t=1319105898
[Thu Oct 20 12:21:25 2011] [error] [client 129.129.194.73] FastCGI: incomplete headers (0 bytes) received from server "/path/to/wiki/bin/foswiki.fcgi", referer: https://our.server.ch/foswiki113x/bin/edit/NameOfTheWeb/WebHomeCopy?t=1319105898

-- OliverSchaub - 20 Oct 2011

Try this patch:

--- lib/Foswiki/Plugins/DBCachePlugin/Core.pm   (revision 12810)
+++ lib/Foswiki/Plugins/DBCachePlugin/Core.pm   (working copy)
@@ -262,6 +262,7 @@
   $theSkip = 0 if $theSkip < 0;
 
   my $theDB = getDB($thisWeb);
+  return '' unless $theDB;
 
   # flag the current web we evaluate this query in, used by web-specific operators
   $dbQueryCurrentWeb = $thisWeb;
@@ -351,6 +352,10 @@
 
   # get form object
   my $baseDB = getDB($thisWeb);
+  unless ($baseDB) {
+    print STDERR "can't get dbcache for '$thisWeb'\n";
+    return undef;
+  }
 
   #writeDebug("1");
 
@@ -452,7 +457,7 @@
       # last resort: lookup the method in the Applications web
       #writeDebug("last resort check for Applications.$thisTopic");
       my $appDB = getDB('Applications');
-      if ($appDB->fastget($thisTopic)) {
+      if ($appDB && $appDB->fastget($thisTopic)) {

-- MichaelDaum - 20 Oct 2011

I applied the Patch but get the same Error-Messages...

-- OliverSchaub - 21 Oct 2011

Any chance of a traceback?

-- MichaelDaum - 22 Oct 2011

I attached a more detailed Log-Entry...

-- OliverSchaub - 24 Oct 2011

Here's another patch that adds an extra check for web existence:

Index: lib/Foswiki/Plugins/DBCachePlugin/Core.pm
===================================================================
--- lib/Foswiki/Plugins/DBCachePlugin/Core.pm   (revision 12865)
+++ lib/Foswiki/Plugins/DBCachePlugin/Core.pm   (working copy)
@@ -262,6 +262,7 @@
   $theSkip = 0 if $theSkip < 0;
 
   my $theDB = getDB($thisWeb);
+  return '' unless $theDB;
 
   # flag the current web we evaluate this query in, used by web-specific operators
   $dbQueryCurrentWeb = $thisWeb;
@@ -351,6 +352,10 @@
 
   # get form object
   my $baseDB = getDB($thisWeb);
+  unless ($baseDB) {
+    print STDERR "can't get dbcache for '$thisWeb'\n";
+    return undef;
+  }
 
   #writeDebug("1");
 
@@ -452,7 +457,7 @@
       # last resort: lookup the method in the Applications web
       #writeDebug("last resort check for Applications.$thisTopic");
       my $appDB = getDB('Applications');
-      if ($appDB->fastget($thisTopic)) {
+      if ($appDB && $appDB->fastget($thisTopic)) {
         $params->{OBJECT} = $theObject;
         $thisWeb = 'Applications';
       }
@@ -474,6 +479,8 @@
 
   # get web and topic
   my $thisDB = getDB($thisWeb);
+  return inlineError("ERROR: DBALL can't find web $thisWeb") unless $thisDB;
+
   my $topicObj = $thisDB->fastget($thisTopic);
   unless ($topicObj) {
     if ($warn) {

Note that this is no SetVariablePlugin error. Moreover it is a DBCachePlugin problem not being robust enuf to eat unknown webs under certain conditions triggered by SetVariablePlugin.

-- MichaelDaum - 24 Oct 2011

This Patch solved the Problems.

Thank you for the quick Help.

-- OliverSchaub - 24 Oct 2011

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