Collect names of multiple erroring parameters

Rather than stop immediately at the first failure, we can be a bit more
helpful by collecting up potentially multiple names at once.

We limit the list to 5 elements, just to limit the potential output in
the case of accidentally passing a list of hundreds or thousands of
elements into such a function.

Author: leonerd

pod/perldiag.pod

@@ -4163,9 +4163,12 @@ which is forbidden.  See L<perlvar/%{^HOOK}> and L<perlfunc/require EXPR>.
 
 =item Missing required named parameter '%s' to subroutine '%s'
 
-(F) A subroutine was invoked that uses a signature that declares a
-non-optional named parameter, but the caller did not provide a value associated
-with that name.  The caller of the subroutine is presumably at fault.
+=item Missing required named parameters '%s' to subroutine '%s'
+
+(F) A subroutine was invoked that uses a signature that declares at least
+one non-optional named parameter, but the caller did not provide a value
+associated with that name.  The caller of the subroutine is presumably at
+fault.
 
 The message attempts to include the name of the called subroutine.  If
 the subroutine has been aliased, the subroutine's original name will be
@@ -7530,10 +7533,12 @@ perl does not recognise the name of the requested attribute.
 
 =item Unrecognized named parameter '%s' to subroutine '%s'
 
-(F) A subroutine was invoked that uses a signature that declares named parameters but has no
-slurpy parameter, and the caller provided a name that did not
-match any declared named parameter.  The caller of the subroutine is
-presumably at fault.
+=item Unrecognized named parameters '%s' to subroutine '%s'
+
+(F) A subroutine was invoked that uses a signature that declares named
+parameters but has no slurpy parameter, and the caller provided at least one
+name that did not match any declared named parameter.  The caller of the
+subroutine is presumably at fault.
 
 The message attempts to include the name of the called subroutine.  If
 the subroutine has been aliased, the subroutine's original name will be

pp.c

@@ -7890,6 +7890,27 @@ PP(pp_argcheck)
     return NORMAL;
 }
 
+/* Helper function for collecting up hash key names for a human-readable
+ * error message string
+ */
+#define accumulate_error_names(n_errorsp, error_namesp, namepv, namelen)  S_accumulate_error_names(aTHX_ n_errorsp, error_namesp, namepv, namelen)
+STATIC void
+S_accumulate_error_names(pTHX_ size_t *n_errorsp, SV **error_namesp, const char *namepv, STRLEN namelen)
+{
+    size_t n_errors = ++(*n_errorsp);
+
+    SV *error_names = (*error_namesp);
+    if(!error_names)
+        error_names = (*error_namesp) = newSVpvs_flags("", SVs_TEMP);
+
+    if(n_errors <= 5) {
+        /* Only bother collecting up the first 5 */
+        if(n_errors > 1)
+            sv_catpvs(error_names, ", ");
+        sv_catpvf(error_names, "'%" UTF8f "'", UTF8fARG(true, namelen, namepv));
+    }
+}
+
 PP(pp_multiparam)
 {
     struct op_multiparam_aux *aux = (struct op_multiparam_aux *)cUNOP_AUX->op_aux;
@@ -7983,6 +8004,9 @@ PP(pp_multiparam)
             SvPADSTALE_on(PAD_SVl(named->padix));
         }
 
+        size_t n_errors = 0;
+        SV *error_names = NULL;
+
         while(argc) {
             SV **svp;
 
@@ -8060,22 +8084,32 @@ PP(pp_multiparam)
                 hv_store_ent(hv, name, newSVsv(val), 0);
             }
             else {
-                // TODO: Consider collecting up all the names of unrecognised
-                // in one string
-                croak_caller("Unrecognized named parameter '%" UTF8f "' to subroutine '%" SVf "'",
-                    UTF8fARG(true, namelen, namepv), S_find_runcv_name());
+                accumulate_error_names(&n_errors, &error_names, namepv, namelen);
             }
         }
 
+        if(n_errors) {
+            if(n_errors > 5)
+                sv_catpvs(error_names, ", ...");
+            /* diag_listed_as: Unrecognized named parameter '%s' to subroutine '%s' */
+            croak_caller("Unrecognized named parameter%s %" SVf " to subroutine '%" SVf "'",
+                n_errors > 1 ? "s" : "", SVfARG(error_names), SVfARG(S_find_runcv_name()));
+        }
+
         for(size_t namedix = 0; namedix < n_named; namedix++) {
             struct op_multiparam_named_aux *named = aux->named + namedix;
             if(!named->is_required || !SvPADSTALE(PAD_SVl(named->padix)))
                 continue;
 
-            // TODO: Consider collecting up all the names of missing
-            // parameters in one string
-            croak_caller("Missing required named parameter '%" UTF8f "' to subroutine '%" SVf "'",
-                    UTF8fARG(true, named->namelen, named->namepv), S_find_runcv_name());
+            accumulate_error_names(&n_errors, &error_names, named->namepv, named->namelen);
+        }
+
+        if(n_errors) {
+            if(n_errors > 5)
+                sv_catpvs(error_names, ", ...");
+            /* diag_listed_as: Missing required named parameter '%s' to subroutine '%s' */
+            croak_caller("Missing required named parameter%s %" SVf " to subroutine '%" SVf "'",
+                n_errors > 1 ? "s" : "", SVfARG(error_names), SVfARG(S_find_runcv_name()));
         }
     }
 

t/lib/croak/signatures

@@ -285,9 +285,30 @@ f(alpha => 123);             ## line 4
 EXPECT
 Missing required named parameter 'beta' to subroutine 'main::f' at - line 4.
 ########
+# NAME multiple missing required named
+no warnings 'experimental::signature_named_parameters';
+sub f (:$alpha, :$beta) { }  ## line 3
+f();                         ## line 4
+EXPECT
+Missing required named parameters 'alpha', 'beta' to subroutine 'main::f' at - line 4.
+########
 # NAME unrecognised named
 no warnings 'experimental::signature_named_parameters';
 sub f (:$alpha) { }             ## line 3
 f(alpha => 123, gamma => 456);  ## line 4
 EXPECT
 Unrecognized named parameter 'gamma' to subroutine 'main::f' at - line 4.
+########
+# NAME multiple unrecognised named
+no warnings 'experimental::signature_named_parameters';
+sub f (:$alpha) { }                           ## line 3
+f(alpha => 123, gamma => 456, delta => 789);  ## line 4
+EXPECT
+Unrecognized named parameters 'gamma', 'delta' to subroutine 'main::f' at - line 4.
+########
+# NAME multiple unrecognised named limiting
+no warnings 'experimental::signature_named_parameters';
+sub f (:$alpha) { }           ## line 3
+f(alpha => 123, 'a' .. 'z');  ## line 4
+EXPECT
+Unrecognized named parameters 'a', 'c', 'e', 'g', 'i', ... to subroutine 'main::f' at - line 4.