Re: [mp2] return value of print can break legacy apps

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Tuomo Salo wrote:
> Under mod_perl2 the return value of print seems to be the number of
> bytes printed. I run across a legacy app (a registry script), that
> frequently used the following idiom:
> 
> 
> print(CGI::redirect("url_to_error_page")) and return if $error;
> 
> 
> While this is obviously a stupid way to write, it seems ok since the
> perldoc for print says: "Prints a string or a list of strings.  Returns
> true if successful."

> Now the redirection will be performed, and an empty string is passed to
> print. print has been overridden by mod_perl2, and will now return the
> number of bytes written, that is, 0. The "and" will naturally
> short-circuit, and the "return" will never be reached.

ok, try this patch.

--Geoff

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Index: xs/maps/modperl_functions.map
===================================================================
--- xs/maps/modperl_functions.map	(revision 111510)
+++ xs/maps/modperl_functions.map	(working copy)
@@ -48,7 +48,7 @@
 
 MODULE=Apache::RequestIO   PACKAGE=Apache::RequestRec
  SV *:DEFINE_TIEHANDLE    | | SV *:stashsv, SV *:sv=Nullsv
- apr_size_t:DEFINE_PRINT  | | ...
+ SV *:DEFINE_PRINT  | | ...
  apr_size_t:DEFINE_PRINTF | | ...
  SV *:DEFINE_BINMODE  | | request_rec *:r
  SV *:DEFINE_CLOSE    | | request_rec *:r
Index: xs/Apache/RequestIO/Apache__RequestIO.h
===================================================================
--- xs/Apache/RequestIO/Apache__RequestIO.h	(revision 111510)
+++ xs/Apache/RequestIO/Apache__RequestIO.h	(working copy)
@@ -75,8 +75,8 @@
 }
 
 static MP_INLINE
-apr_size_t mpxs_Apache__RequestRec_print(pTHX_ I32 items,
-                                         SV **MARK, SV **SP)
+SV *mpxs_Apache__RequestRec_print(pTHX_ I32 items,
+                                 SV **MARK, SV **SP)
 {
     modperl_config_req_t *rcfg;
     request_rec *r;
@@ -95,7 +95,7 @@
     
     mpxs_output_flush(r, rcfg, "Apache::RequestIO::print");
     
-    return bytes;
+    return bytes ? newSVuv(bytes) : newSVpvn("0E0", 3);
 }  
 
 static MP_INLINE
Index: xs/tables/current/ModPerl/FunctionTable.pm
===================================================================
--- xs/tables/current/ModPerl/FunctionTable.pm	(revision 111510)
+++ xs/tables/current/ModPerl/FunctionTable.pm	(working copy)
@@ -6766,7 +6766,7 @@
     ]
   },
   {
-    'return_type' => 'apr_size_t',
+    'return_type' => 'SV *',
     'name' => 'mpxs_Apache__RequestRec_print',
     'args' => [
       {
Index: t/response/TestModperl/print.pm
===================================================================
--- t/response/TestModperl/print.pm	(revision 111510)
+++ t/response/TestModperl/print.pm	(working copy)
@@ -12,7 +12,7 @@
 sub handler {
     my $r = shift;
 
-    plan $r, tests => 3;
+    plan $r, tests => 6;
 
     binmode STDOUT; #Apache::RequestRec::BINMODE (noop)
 
@@ -20,8 +20,23 @@
 
     ok 2;
 
-    printf "ok %d\n", 3;
+    {
+        # print should return true on success, even
+        # if it sends no data.
+        my $rc = print '';
 
+        ok ($rc);
+        ok ($rc == 0);  # 0E0 is still numerically 0
+    }
+
+    {
+        my $rc = print "# 11 bytes\n";  # don't forget the newline
+
+        ok ($rc == 11);
+    }
+
+    printf "ok %d\n", 6;
+
     Apache::OK;
 }
 
Index: t/response/TestAPI/request_rec.pm
===================================================================
--- t/response/TestAPI/request_rec.pm	(revision 111510)
+++ t/response/TestAPI/request_rec.pm	(working copy)
@@ -95,7 +95,7 @@
     {
         local $| = 0;
         ok t_cmp $r->print("# buffered\n"), 11, "buffered print";
-        ok t_cmp $r->print(), 0, "buffered print";
+        ok t_cmp $r->print(), "0E0", "buffered print";
 
         local $| = 1;
         my $string = "# not buffered\n";


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