protect $@ whenever a block using $@ is non-trivial

As noted in the Try::Tiny man page, eval/$@ can be quite awkward in
corner cases, because $@ has the same properties and problems as C's
errno. While writing a regression test for definetemplate
in which it couldn't find an appropriate template, I received

    <span class="error">Error: failed to process template
    <span class="createlink">deftmpl</span> </span>

instead of the intended

    <span class="error">Error: failed to process template
    <span class="createlink">deftmpl</span> template deftmpl not
    found</span>

which turned out to be because the "catch"-analogous block called
gettext before it used $@, and gettext can call define_gettext,
which uses eval.

This commit alters all current "catch"-like blocks that use $@, except
those that just do trivial things with $@ (string interpolation, string
concatenation) and call a function (die, error, print, etc.)

1 files changed, 2 insertions, 1 deletions

diff --git a/IkiWiki/CGI.pm b/IkiWiki/CGI.pm
index 5baa6c179..c0d8f598b 100644
--- a/IkiWiki/CGI.pm
+++ b/IkiWiki/CGI.pm
@@ -351,7 +351,8 @@ sub cgi_getsession ($) {
 			{ FileName => "$config{wikistatedir}/sessions.db" })
 	};
 	if (! $session || $@) {
-		error($@." ".CGI::Session->errstr());
+		my $error = $@;
+		error($error." ".CGI::Session->errstr());
 	}
 	
 	umask($oldmask);