[perl #73754] Better error message for PerlIO layer implementations

please find attached a patch against blead originating from [1] ,
that improves the "Layer does not match this perl" error message by
telling the user which IO layer failed and how. I've tested the
patch against a recent bleadperl and even without the modifications
to perldiag.t all tests pass. Still, for completeness, I've patched
perldiag.t as well.

The code is not mine, it was written and posted by Tye McQueen, I've
just tested it [2] and ferry the information. I'm aware that this
patch is too late for 5.12 , but in the sense of improving Perl in
the long run, I hope the change still makes it into a version of
Perl.

-max

[1] http://perlmonks.org/?node_id=829815
[2] Certified Works On My Machine, 2010

diff --git a/perlio.c b/perlio.c
index 79b7efa..547f0b4 100644 (file)
--- a/perlio.c
+++ b/perlio.c
@@ -1211,13 +1211,18 @@ PerlIO *
 PerlIO_push(pTHX_ PerlIO *f, PERLIO_FUNCS_DECL(*tab), const char *mode, SV *arg)
 {
     if (tab->fsize != sizeof(PerlIO_funcs)) {
-      mismatch:
-       Perl_croak(aTHX_ "Layer does not match this perl");
+       Perl_croak( aTHX_
+           "%s (%d) does not match %s (%d)",
+           "PerlIO layer function table size", tab->fsize,
+           "size expected by this perl", sizeof(PerlIO_funcs) );
     }
     if (tab->size) {
        PerlIOl *l;
        if (tab->size < sizeof(PerlIOl)) {
-           goto mismatch;
+           Perl_croak( aTHX_
+               "%s (%d) smaller than %s (%d)",
+               "PerlIO layer instance size", tab->size,
+               "size expected by this perl", sizeof(PerlIOl) );
        }
        /* Real layer with a data area */
        if (f) {

diff --git a/t/porting/diag.t b/t/porting/diag.t
index 3617342..2978a5b 100644 (file)
--- a/t/porting/diag.t
+++ b/t/porting/diag.t
@@ -276,6 +276,8 @@ sub check_file {
 # PLEASE DO NOT ADD TO THIS LIST.  Instead, write an entry in
 # pod/perldiag.pod for your new (warning|error).
 __DATA__
+%s (%d) does not match %s (%d),
+%s (%d) smaller than %s (%d),
 Argument "%s" isn't numeric
 Argument "%s" isn't numeric in %s
 Attempt to clear deleted array
@@ -368,7 +370,6 @@ Invalid type ',' in %s
 It is proposed that "\c{" no longer be valid. It has historically evaluated to  ";".  If you disagree with this proposal, send email to perl5-porters@perl.org Otherwise, or in the meantime, you can work around this failure by changing "\c{" to ";"
 'j' not supported on this platform
 'J' not supported on this platform
-Layer does not match this perl
 leaving effective gid failed
 leaving effective uid failed
 List form of piped open not implemented