Bug 351175: The WebService interface should include the error text along with the error name

Patch By Max Kanat-Alexander <mkanat@bugzilla.org> r=Wurblzap, a=myk

webtools/bugzilla/Bugzilla/Error.pm

@@ -81,16 +81,21 @@ sub _throw_error {
         $template->process($name, $vars)
           || ThrowTemplateError($template->error());
     }
-    elsif (Bugzilla->error_mode == ERROR_MODE_DIE) {
+    else {
         my $message;
         $template->process($name, $vars, \$message)
           || ThrowTemplateError($template->error());
-        die("$message\n");
-    }
-    elsif (Bugzilla->error_mode == ERROR_MODE_DIE_SOAP_FAULT) {
-        die SOAP::Fault
-            ->faultcode(ERROR_GENERAL)
-            ->faultstring($error);
+        if (Bugzilla->error_mode == ERROR_MODE_DIE) {
+            die("$message\n");
+        }
+        elsif (Bugzilla->error_mode == ERROR_MODE_DIE_SOAP_FAULT) {
+            my $code = WS_ERROR_CODE->{$error};
+            if (!$code) {
+                $code = ERROR_UNKNOWN_FATAL if $name =~ /code/i;
+                $code = ERROR_UNKNOWN_TRANSIENT if $name =~ /user/i;
+            }
+            die SOAP::Fault->faultcode($code)->faultstring($message);
+        }
     }
     exit;
 }

webtools/bugzilla/Bugzilla/WebService.pm

@@ -13,6 +13,7 @@
 # The Original Code is the Bugzilla Bug Tracking System.
 #
 # Contributor(s): Marc Schumann <wurblzap@gmail.com>
+#                 Max Kanat-Alexander <mkanat@bugzilla.org>
 
 package Bugzilla::WebService;
 
@@ -75,3 +76,39 @@ Certain parts of a method's description may be marked as B<UNSTABLE>,
 in which case those parts are not guaranteed to stay the same between
 Bugzilla versions.
 
+=head1 ERRORS
+
+If a particular webservice call fails, it will throw a standard XML-RPC
+error. There will be a numeric error code, and then the description
+field will contain descriptive text of the error. Each error that Bugzilla
+can throw has a specific code that will not change between versions of
+Bugzilla.
+
+The various errors that functions can throw are specified by the
+documentation of those functions.
+
+If your code needs to know what error Bugzilla threw, use the numeric
+code. Don't try to parse the description, because that may change
+from version to version of Bugzilla.
+
+Note that if you display the error to the user in an HTML program, make
+sure that you properly escape the error, as it will not be HTML-escaped.
+
+=head2 Transient vs. Fatal Errors
+
+If the error code is a number greater than 0, the error is considered
+"transient," which means that it was an error made by the user, not
+some problem with Bugzilla itself.
+
+If the error code is a number less than 0, the error is "fatal," which
+means that it's some error in Bugzilla itself that probably requires
+administrative attention.
+
+Negative numbers and positive numbers don't overlap. That is, if there's
+an error 302, there won't be an error -302.
+
+=head2 Unknown Errors
+
+Sometimes a function will throw an error that doesn't have a specific
+error code. In this case, the code will be C<-32000> if it's a "fatal"
+error, and C<32000> if it's a "transient" error.

webtools/bugzilla/Bugzilla/WebService/Constants.pm

@@ -13,6 +13,7 @@
 # The Original Code is the Bugzilla Bug Tracking System.
 #
 # Contributor(s): Marc Schumann <wurblzap@gmail.com>
+#                 Max Kanat-Alexander <mkanat@bugzilla.org>
 
 package Bugzilla::WebService::Constants;
 
@@ -20,11 +21,49 @@ use strict;
 use base qw(Exporter);
 
 @Bugzilla::WebService::Constants::EXPORT = qw(
+    WS_ERROR_CODE
+    ERROR_UNKNOWN_FATAL
+    ERROR_UNKNOWN_TRANSIENT
+
     ERROR_AUTH_NODATA
     ERROR_UNIMPLEMENTED
-    ERROR_GENERAL
 );
 
+# This maps the error names in global/*-error.html.tmpl to numbers.
+# Generally, transient errors should have a number above 0, and
+# fatal errors should have a number below 0.
+#
+# This hash should generally contain any error that could be thrown
+# by the WebService interface. If it's extremely unlikely that the
+# error could be thrown (like some CodeErrors), it doesn't have to
+# be listed here.
+#
+# "Transient" means "If you resubmit that request with different data,
+# it may work."
+#
+# "Fatal" means, "There's something wrong with Bugzilla, probably
+# something an administrator would have to fix."
+#
+# NOTE: Numbers must never be recycled. If you remove a number, leave a
+# comment that it was retired. Also, if an error changes its name, you'll
+# have to fix it here.
+use constant WS_ERROR_CODE => {
+    # Bug errors usually occupy the 100-200 range.
+    invalid_bug_id_or_alias     => 100,
+    invalid_bug_id_non_existent => 101,
+    bug_access_denied           => 102,
+
+    # Authentication errors are usually 300-400.
+    invalid_username_or_password => 300,
+    account_disabled             => 301,
+    auth_invalid_email           => 302,
+    extern_id_conflict           => -303,
+};
+
+# These are the fallback defaults for errors not in ERROR_CODE.
+use constant ERROR_UNKNOWN_FATAL     => -32000;
+use constant ERROR_UNKNOWN_TRANSIENT => 32000;
+
 use constant ERROR_AUTH_NODATA   => 410;
 use constant ERROR_UNIMPLEMENTED => 910;
 use constant ERROR_GENERAL       => 999;

webtools/bugzilla/t/012throwables.t

@@ -19,6 +19,7 @@
 # Rights Reserved.
 # 
 # Contributor(s): Dennis Melentyev <dennis.melentyev@infopulse.com.ua>
+#                 Max Kanat-Alexander <mkanat@bugzilla.org>
 
 
 
@@ -30,6 +31,8 @@ use strict;
 
 use lib 't';
 
+use Bugzilla::WebService::Constants;
+
 use File::Spec;
 use Support::Files;
 use Support::Templates;
@@ -63,8 +66,8 @@ foreach my $include_path (@include_paths) {
     }
 }
 
-# Count the tests
-my $tests = (scalar keys %test_modules) + (scalar keys %test_templates);
+# Count the tests. The +1 is for checking the WS_ERROR_CODE errors.
+my $tests = (scalar keys %test_modules) + (scalar keys %test_templates) + 1;
 exit 0 if !$tests;
 
 # Set requested tests counter.
@@ -162,11 +165,27 @@ foreach my $errtype (keys %Errors) {
     }
 }
 
+# And make sure that everything defined in WS_ERROR_CODE
+# is actually a valid error.
+foreach my $err_name (keys %{WS_ERROR_CODE()}) {
+    if (!defined $Errors{'code'}{$err_name} 
+        && !defined $Errors{'user'}{$err_name})
+    {
+        Register(\%test_modules, 'WS_ERROR_CODE',
+            "Error tag '$err_name' is used in WS_ERROR_CODE in"
+            . " Bugzilla/WebService/Constants.pm"
+            . " but not defined in any template, and not used in any code.");
+    }
+}
+
 # Now report modules results
 foreach my $file (sort keys %test_modules) {
     Report($file, @{$test_modules{$file}});
 }
 
+# And report WS_ERROR_CODE results
+Report('WS_ERROR_CODE', @{$test_modules{'WS_ERROR_CODE'}});
+
 # Now report templates results
 foreach my $file (sort keys %test_templates) {
     Report($file, @{$test_templates{$file}});