Add a cexts test that all headers are warnings-free

* Some C extensions use -Werror and so the headers need to pass that.

Author: eregon

CHANGELOG.md

@@ -34,6 +34,7 @@ Compatibility:
 * Improve support of `:chomp` keyword argument in `IO` and `StringIO` methods (#2650, @andrykonchin). 
 * Implement specializations for immutable ruby objects for ObjectSpace methods (@bjfish).
 * Use `$PAGER` for `--help` and `--help*`, similar to CRuby (#2542, @Strech).
+* Ensure all headers are warnings-free (#2662, @eregon).
 
 Performance:
 

lib/cext/ABI_version.txt

@@ -1 +1 @@
-5
+6

lib/cext/include/ruby/internal/core/rarray.h

@@ -161,7 +161,11 @@ RARRAY_LENINT(VALUE ary)
 RBIMPL_ATTR_PURE_UNLESS_DEBUG()
 RBIMPL_ATTR_ARTIFICIAL()
 static inline bool
+#ifdef TRUFFLERUBY
+RARRAY_TRANSIENT_P(RB_UNUSED_VAR(VALUE ary))
+#else
 RARRAY_TRANSIENT_P(VALUE ary)
+#endif
 {
     RBIMPL_ASSERT_TYPE(ary, RUBY_T_ARRAY);
 

lib/cext/include/ruby/internal/rgengc.h

@@ -171,21 +171,27 @@ rb_obj_wb_unprotect(VALUE x, RB_UNUSED_VAR(const char *filename), RB_UNUSED_VAR(
 }
 #endif // TRUFFLERUBY
 
+#ifdef TRUFFLERUBY
+static inline VALUE
+rb_obj_written(VALUE a, RB_UNUSED_VAR(VALUE oldv), RB_UNUSED_VAR(VALUE b), RB_UNUSED_VAR(const char *filename), RB_UNUSED_VAR(int line))
+{
+    return a;
+}
+#else
 static inline VALUE
 rb_obj_written(VALUE a, RB_UNUSED_VAR(VALUE oldv), VALUE b, RB_UNUSED_VAR(const char *filename), RB_UNUSED_VAR(int line))
 {
 #if USE_RGENGC_LOGGING_WB_UNPROTECT
     RGENGC_LOGGING_OBJ_WRITTEN(a, oldv, b, filename, line);
 #endif
 
-#ifndef TRUFFLERUBY
     if (!RB_SPECIAL_CONST_P(b)) {
         rb_gc_writebarrier(a, b);
     }
-#endif
 
     return a;
 }
+#endif
 
 static inline VALUE
 rb_obj_write(VALUE a, VALUE *slot, VALUE b, RB_UNUSED_VAR(const char *filename), RB_UNUSED_VAR(int line))

lib/cext/include/ruby/internal/special_consts.h

@@ -163,7 +163,11 @@ RBIMPL_ATTR_CONST()
 RBIMPL_ATTR_CONSTEXPR(CXX11)
 RBIMPL_ATTR_ARTIFICIAL()
 static inline bool
+#ifdef TRUFFLERUBY
+RB_FLONUM_P(RB_UNUSED_VAR(VALUE obj))
+#else
 RB_FLONUM_P(VALUE obj)
+#endif
 {
 #if USE_FLONUM
     return (obj & RUBY_FLONUM_MASK) == RUBY_FLONUM_FLAG;

lib/cext/include/truffleruby/truffleruby.h

@@ -224,12 +224,12 @@ ALWAYS_INLINE(static int rb_tr_scan_args_kw_int(int kw_flag, int argc, VALUE *ar
 static inline int rb_tr_scan_args_kw_int(int kw_flag, int argc, VALUE *argv, struct rb_tr_scan_args_parse_data parse_data, VALUE *v1, VALUE *v2, VALUE *v3, VALUE *v4, VALUE *v5, VALUE *v6, VALUE *v7, VALUE *v8, VALUE *v9, VALUE *v10) {
 
   int keyword_given = 0;
-  int last_hash_keyword = 0;
+  // int last_hash_keyword = 0;
 
   switch (kw_flag) {
     case RB_SCAN_ARGS_PASS_CALLED_KEYWORDS: break;
     case RB_SCAN_ARGS_KEYWORDS: keyword_given = 1; break;
-    case RB_SCAN_ARGS_LAST_HASH_KEYWORDS: last_hash_keyword = 1; break;
+    case RB_SCAN_ARGS_LAST_HASH_KEYWORDS: /* last_hash_keyword = 1; not used currently */ break;
   }
 
   // Check we have enough arguments

test/truffle/cexts/werror/bin/werror

@@ -0,0 +1,3 @@
+#!/usr/bin/env ruby
+
+require 'werror/werror'

test/truffle/cexts/werror/expected.txt

@@ -0,0 +1 @@
+Hello!

test/truffle/cexts/werror/ext/werror/extconf.rb

@@ -0,0 +1,4 @@
+require 'mkmf'
+# No -pedantic because polyglot-impl.h fails that, and well, it's too pedantic
+$warnflags << ' -W -Wall -Wextra -Werror'
+create_makefile('werror')

test/truffle/cexts/werror/ext/werror/werror.c

@@ -0,0 +1,6 @@
+#include <stdio.h>
+#include <ruby.h>
+
+void Init_werror() {
+  printf("Hello!\n");
+}