Item4692: Forking search algorithm throws error if topic is nonexistent

Example

Do a search like

%SEARCH{ "Test" web="%WEB%" topic="SomeNonExistentPage" }%

with the TWiki::Store::SearchAlgorithms::Forking algorithm. In the "rendered" page you get an error of the form

 Could not perform search. Error was: /bin/grep -F -i -l -H -- %TOKEN|U% %FILES|F% Grep for 'Test' returned error

If you choose some e.g. TWiki::Store::SearchAlgorithms::PurePerl as your search algo, you get no errors (and no hits, of course).

Reason

Taking a look at Forking.pm, you can see

throw Error::Simple("$program Grep for '$searchString' returned error")
  if $exit > 1;

But grep's return error code is 2, because the topic cannot be found.

This behaviour is new to 4.2 and differs from 4.1.2.

-- TWiki:Main/ChristianLudwig - 21 Sep 2007

Flip side of this, is that perhaps TWiki should not be calling grep on topics that don't exist - as each fork of a process is slow.

Good find!

-- TWiki:Main.SvenDowideit - 21 Sep 2007

I changed the grep command from /bin/egrep to /bin/grep -E for consistency with Windows. Looks like it may have been a bad move

A testcase is required for this.

-- TWiki:Main.CrawfordCurrie - 22 Sep 2007

Fixed

CC