Add category to `rb_warn_deprecated`

PR https://github.com/ruby/ruby/pull/3418 added a category to
`rb_warn_deprecated_to_remove` but not to `rb_warn_deprecated`. This
adds the same code to `rb_warn_deprecated` so that those warnings also
get a category.

This change also adds tests for `rb_warn_deprecated` and updates the
tests for `rb_warn_deprecated_to_remove` to have clearer names.

I've fixed the call to `rb_method_entry` as we need to be using the
instance method, not singleton.

Feature: https://bugs.ruby-lang.org/issues/17122

1 files changed, 17 insertions, 2 deletions

diff --git a/error.c b/error.c
index 841ab6c97f..a9adf57162 100644
--- a/error.c
+++ b/error.c
@@ -392,7 +392,22 @@ rb_warn_deprecated(const char *fmt, const char *suggest, ...)
     rb_str_cat_cstr(mesg, " is deprecated");
     if (suggest) rb_str_catf(mesg, "; use %s instead", suggest);
     rb_str_cat_cstr(mesg, "\n");
-    rb_write_warning_str(mesg);
+
+    VALUE warn_args[2];
+    warn_args[0] = mesg;
+
+    const rb_method_entry_t * me;
+    me = rb_method_entry(rb_singleton_class(rb_mWarning), id_warn);
+
+    if (rb_method_entry_arity(me) != 1) {
+        VALUE kwargs = rb_hash_new();
+        rb_hash_aset(kwargs, ID2SYM(rb_intern("category")), ID2SYM(rb_intern("deprecated")));
+        warn_args[1] = kwargs;
+
+        rb_funcallv_kw(rb_mWarning, id_warn, 2, warn_args, RB_PASS_KEYWORDS);
+    } else {
+        rb_funcall(rb_mWarning, id_warn, 1, mesg);
+    }
 }
 
 void
@@ -411,7 +426,7 @@ rb_warn_deprecated_to_remove(const char *fmt, const char *removal, ...)
     warn_args[0] = mesg;
 
     const rb_method_entry_t * me;
-    me = rb_method_entry(rb_mWarning, id_warn);
+    me = rb_method_entry(rb_singleton_class(rb_mWarning), id_warn);
 
     if (rb_method_entry_arity(me) != 1) {
         VALUE kwargs = rb_hash_new();