don't strip keyword argument names with --strip-metadata (#58412)

These are used by `hasmethod`, and in any case including keyword
argument symbols is unavoidable so there is no cost to keeping these.

(cherry picked from commit c5df018)

Author: JeffBezanson

src/staticdata.c

@@ -2612,12 +2612,12 @@ static void jl_prune_module_bindings(jl_module_t * m) JL_GC_DISABLED
     jl_gc_wb(m, jl_atomic_load_relaxed(&bindingkeyset2));
 }
 
-static void strip_slotnames(jl_array_t *slotnames)
+static void strip_slotnames(jl_array_t *slotnames, int n)
 {
     // replace slot names with `?`, except unused_sym since the compiler looks at it
     jl_sym_t *questionsym = jl_symbol("?");
-    int i, l = jl_array_len(slotnames);
-    for (i = 0; i < l; i++) {
+    int i;
+    for (i = 0; i < n; i++) {
         jl_value_t *s = jl_array_ptr_ref(slotnames, i);
         if (s != (jl_value_t*)jl_unused_sym)
             jl_array_ptr_set(slotnames, i, questionsym);
@@ -2636,7 +2636,7 @@ static jl_value_t *strip_codeinfo_meta(jl_method_t *m, jl_value_t *ci_, jl_code_
     else {
         ci = (jl_code_info_t*)ci_;
     }
-    strip_slotnames(ci->slotnames);
+    strip_slotnames(ci->slotnames, jl_array_len(ci->slotnames));
     ci->debuginfo = jl_nulldebuginfo;
     jl_gc_wb(ci, ci->debuginfo);
     jl_value_t *ret = (jl_value_t*)ci;
@@ -2710,7 +2710,11 @@ static int strip_all_codeinfos__(jl_typemap_entry_t *def, void *_env)
             }
             jl_array_t *slotnames = jl_uncompress_argnames(m->slot_syms);
             JL_GC_PUSH1(&slotnames);
-            strip_slotnames(slotnames);
+            int tostrip = jl_array_len(slotnames);
+            // for keyword methods, strip only nargs to keep the keyword names at the end for reflection
+            if (jl_tparam0(jl_unwrap_unionall(m->sig)) == jl_typeof(jl_kwcall_func))
+                tostrip = m->nargs;
+            strip_slotnames(slotnames, tostrip);
             m->slot_syms = jl_compress_argnames(slotnames);
             jl_gc_wb(m, m->slot_syms);
             JL_GC_POP();

test/cmdlineargs.jl

@@ -1271,3 +1271,13 @@ end
     timeout = 120
     @test parse(Int,read(`$exename --timeout-for-safepoint-straggler=$timeout -E "Base.JLOptions().timeout_for_safepoint_straggler_s"`, String)) == timeout
 end
+
+@testset "--strip-metadata" begin
+    mktempdir() do dir
+        @test success(pipeline(`$(Base.julia_cmd()) --strip-metadata -t1,0 --output-o $(dir)/sys.o.a -e 0`, stderr=stderr, stdout=stdout))
+        if isfile(joinpath(dir, "sys.o.a"))
+            Base.Linking.link_image(joinpath(dir, "sys.o.a"), joinpath(dir, "sys.so"))
+            @test readchomp(`$(Base.julia_cmd()) -t1,0 -J $(dir)/sys.so -E 'hasmethod(sort, (Vector{Int},), (:dims,))'`) == "true"
+        end
+    end
+end