Make exception class an actual class.

This is a long-overdue change that allows for overloading the
stringification operator to produce better error messages.
BuildException was previously not an actual module since kdesrc-build
itself was just a single script file. Now that we allow modules on disk
there is no reason to leave the exception class as a figment of Perl's
imagination.

CMakeLists.txt

@@ -19,6 +19,7 @@ if (KDESRC_BUILD_INSTALL_MODULES)
     message(STATUS "Installing component modules to ${KDESRC_BUILD_MODULE_INSTALL_PREFIX}")
     install(FILES
         modules/ksb/BuildContext.pm
+        modules/ksb/BuildException.pm
         modules/ksb/BuildSystem.pm
         modules/ksb/Debug.pm
         modules/ksb/DependencyResolver.pm

kdesrc-build

@@ -2999,7 +2999,7 @@ eval
 
 if (my $err = $@)
 {
-    if (ref $err && $err->isa('BuildException')) {
+    if (ref $err && $err->isa('ksb::BuildException')) {
         print $err->{'exception_type'}, " error: ", $err->{'message'}, "\n";
         print "\tCan't continue, so stopping now.\n";
 

kdesrc-build-test.pl

@@ -450,7 +450,7 @@ $@ = '';
 eval {
     @filtered_modules = applyModuleFilters($ctx, @conf_modules);
 };
-isa_ok($@, 'BuildException', 'resume-{from,after} combine for exception');
+isa_ok($@, 'ksb::BuildException', 'resume-{from,after} combine for exception');
 
 $ctx->deleteOption('resume-from');
 @filtered_modules = applyModuleFilters($ctx, @conf_modules);
@@ -615,7 +615,7 @@ done_testing();
 }; # eval
 
 if (my $err = $@) {
-    if (blessed ($err) && $err->isa('BuildException')) {
+    if (blessed ($err) && $err->isa('ksb::BuildException')) {
         say "Test suite failed after kdesrc-build threw the following exception:";
         say "$@->{message}";
         fail();

modules/ksb/BuildException.pm

@@ -0,0 +1,30 @@
+package ksb::BuildException;
+
+# A class to wrap 'exception' messages for the script, allowing them to be
+# dispatch based on type and automatically stringified.
+
+use v5.10; # Needed for state keyword
+use strict;
+use warnings;
+use overload
+    '""' => \&to_string;
+
+our $VERSION = '0.10';
+
+sub new
+{
+    my ($class, $type, $msg) = @_;
+
+    return bless({
+        'exception_type' => $type,
+        'message'        => $msg,
+    }, $class);
+}
+
+sub to_string
+{
+    my $exception = shift;
+    return $exception->{exception_type} . " Error: " . $exception->{message};
+}
+
+1;

modules/ksb/Module.pm

@@ -700,7 +700,7 @@ sub update
     {
         my $reason = ksb::IPC::MODULE_FAILURE;
 
-        if (ref $@ && $@->isa('BuildException')) {
+        if (ref $@ && $@->isa('ksb::BuildException')) {
             if ($@->{'exception_type'} eq 'ConflictPresent') {
                 $reason = ksb::IPC::MODULE_CONFLICT;
             }

modules/ksb/Updater/Svn.pm

@@ -666,10 +666,6 @@ sub svnInfo
 
     if($@)
     {
-        if (ref $@ && $@->isa('BuildException')) {
-            $@ = $@->{message};
-        }
-
         error ("Unable to run r[b[svn], is the Subversion program installed?");
         error (" -- Error was: r[$@]");
         return undef;

modules/ksb/Util.pm

@@ -17,6 +17,7 @@ use Digest::MD5;
 
 use ksb::Debug;
 use ksb::Version qw(scriptVersion);
+use ksb::BuildException;
 
 use Exporter qw(import); # Use Exporter's import method
 our @EXPORT = qw(list_has make_exception assert_isa assert_in any
@@ -62,10 +63,10 @@ sub absPathToExecutable
 
 # Returns a Perl object worth "die"ing for. (i.e. can be given to the die
 # function and handled appropriately later with an eval). The returned
-# reference will be an instance of BuildException. The actual exception
-# type is passed in as the first parameter (as a string), and can be
-# retrieved from the object later using the 'exception_type' key, and the
-# message is returned as 'message'
+# reference will be an instance of ksb::BuildException. The actual exception
+# type is passed in as the first parameter (as a string), and can be retrieved
+# from the object later using the 'exception_type' key, and the message is
+# returned as 'message'
 #
 # First parameter: Exception type. Recommended are one of: Config, Internal
 # (for logic errors), Runtime (other runtime errors which are not logic
@@ -82,10 +83,7 @@ sub make_exception
     local $Carp::CarpLevel = 1 + $levels;
 
     $message = Carp::cluck($message) if $exception_type eq 'Internal';
-    return bless({
-        'exception_type' => $exception_type,
-        'message'        => $message,
-    }, 'BuildException');
+    return ksb::BuildException->new($exception_type, $message);
 }
 
 # Should be used for "runtime errors" (i.e. unrecoverable runtime problems that