13 files changed, 234 insertions(+), 125 deletions(-)

M PLAN.md
M cmd/conformance/core.lua
M cmd/protoc-gen-tarantool/internal/gen/inline.go
M examples/expected/full/conformance/conformance_pb.lua
M examples/expected/full/hello/hello_pb.lua
M examples/expected/full/protobuf_test_messages/proto3/test_messages_proto3_pb.lua
M runtime/pb/codec.lua
M runtime/pb/lazy.lua
M runtime/pb/text.lua
M runtime/pb/wire.lua
M runtime/pb/wkt.lua
M test/conformance/known_failures_text.txt
M test/conformance_test.lua

@@ 145,17 145,19 @@ fiber and bridges client ↔ handler via `fiber.channel`. All four flavors
       and `test/conformance/known_failures_text.txt` (text-format
       suite). Current baseline (2026-05-16):
         - Binary+JSON suite: 1478 ✓ / 1313 skipped /  15 expected fails
-        - Text-format suite:    2 ✓ /  426 skipped /   6 expected fails
+        - Text-format suite:    8 ✓ /  426 skipped /   0 expected fails
       JSON output runs end-to-end; remaining expected fails are
       Recommended-only edge cases (FieldMask round-trip,
       duplicate-field-name rejection, null-in-collection rejection,
       unknown-enum-name rejection, NullValue oneof validator).
-      Text-format output is wired through `pb.text.encode`; the six
-      expected fails are all unknown-field cases (Group/Repeated parse
-      rejection, *_Print not rendering captured unknowns). Text-format
-      *input* parsing is still deferred. The `PB_CONFORMANCE_SKIP_JSON=1`
-      env var still short-circuits JSON output if a new encoder bug
-      crashes jsoncpp.
+      Text-format output is wired through `pb.text.encode` and the
+      proto3 text suite is fully clean: SGROUP/EGROUP are tolerated in
+      `wire.skip_field` and `pb.text` renders captured unknown bytes in
+      numeric field-ID form under `opts.print_unknown_fields`. The 426
+      still-skipped tests are proto2/editions message types we don't
+      register. Text-format *input* parsing is still deferred. The
+      `PB_CONFORMANCE_SKIP_JSON=1` env var still short-circuits JSON
+      output if a new encoder bug crashes jsoncpp.
       CI wire-up pending — the image build is the long pole (~10–15 min
       on a clean cache).
 - [x] Cross-impl interop: 18-fixture corpus in `test/interop/fixtures/`

@@ 96,7 96,8 @@ local function dispatch(req)
         end
         return {json_payload = jbytes}
     elseif out_fmt == TEXT_FORMAT then
-        local ok, tbytes = pcall(pb.text.encode, desc, msg)
+        local opts = {print_unknown_fields = req.print_unknown_fields == true}
+        local ok, tbytes = pcall(pb.text.encode, desc, msg, opts)
         if not ok then
             return {serialize_error = 'text encode failed: ' ..
                 tostring(tbytes)}

@@ 270,7 270,7 @@ func emitInlineDecode(w *writer, name string, m *protogen.Message, file *protoge
 		w.line("        if true then")
 	}
 	w.line("        else")
-	w.line("            pos = wire.skip_field(buf, pos, wt)")
+	w.line("            pos = wire.skip_field(buf, pos, wt, id)")
 	w.line("            if _uf == nil then _uf = {} end")
 	w.line("            _uf[#_uf + 1] = buf:sub(_tag_start, pos - 1)")
 	w.line("        end")


@@ 527,7 527,7 @@ func emitInlineDecodeMap(w *writer, f *protogen.Field, fname string, file *proto
 	w.line("                elseif eid == 2 then")
 	emitMapDecode(w, "_val", valF, file, selfPath, imports, prefix)
 	w.line("                else")
-	w.line("                    _ep = wire.skip_field(payload, _ep, ewt)")
+	w.line("                    _ep = wire.skip_field(payload, _ep, ewt, eid)")
 	w.line("                end")
 	w.line("            end")
 	if mapKeyNeedsCdataDedup(keyF) {

@@ 193,7 193,7 @@ function M.TestStatus_decode(buf)
             val, pos = wire.decode_string(buf, pos)
             result.matched_name = val
         else
-            pos = wire.skip_field(buf, pos, wt)
+            pos = wire.skip_field(buf, pos, wt, id)
             if _uf == nil then _uf = {} end
             _uf[#_uf + 1] = buf:sub(_tag_start, pos - 1)
         end


@@ 258,7 258,7 @@ function M.FailureSet_decode(buf)
             payload, pos = wire.decode_len(buf, pos)
             list[#list + 1] = M.TestStatus_decode(payload)
         else
-            pos = wire.skip_field(buf, pos, wt)
+            pos = wire.skip_field(buf, pos, wt, id)
             if _uf == nil then _uf = {} end
             _uf[#_uf + 1] = buf:sub(_tag_start, pos - 1)
         end


@@ 439,7 439,7 @@ function M.ConformanceRequest_decode(buf)
             val, pos = wire.decode_bool(buf, pos)
             result.print_unknown_fields = val
         else
-            pos = wire.skip_field(buf, pos, wt)
+            pos = wire.skip_field(buf, pos, wt, id)
             if _uf == nil then _uf = {} end
             _uf[#_uf + 1] = buf:sub(_tag_start, pos - 1)
         end


@@ 668,7 668,7 @@ function M.ConformanceResponse_decode(buf)
             result.skipped = nil
             result.jspb_payload = nil
         else
-            pos = wire.skip_field(buf, pos, wt)
+            pos = wire.skip_field(buf, pos, wt, id)
             if _uf == nil then _uf = {} end
             _uf[#_uf + 1] = buf:sub(_tag_start, pos - 1)
         end


@@ 726,7 726,7 @@ function M.JspbEncodingConfig_decode(buf)
             val, pos = wire.decode_bool(buf, pos)
             result.use_jspb_array_any_format = val
         else
-            pos = wire.skip_field(buf, pos, wt)
+            pos = wire.skip_field(buf, pos, wt, id)
             if _uf == nil then _uf = {} end
             _uf[#_uf + 1] = buf:sub(_tag_start, pos - 1)
         end

@@ 235,7 235,7 @@ function M.Result_decode(buf)
             result.text = nil
             result.code = nil
         else
-            pos = wire.skip_field(buf, pos, wt)
+            pos = wire.skip_field(buf, pos, wt, id)
             if _uf == nil then _uf = {} end
             _uf[#_uf + 1] = buf:sub(_tag_start, pos - 1)
         end


@@ 294,7 294,7 @@ function M.HelloRequest_decode(buf)
             val, pos = wire.decode_string(buf, pos)
             result.name = val
         else
-            pos = wire.skip_field(buf, pos, wt)
+            pos = wire.skip_field(buf, pos, wt, id)
             if _uf == nil then _uf = {} end
             _uf[#_uf + 1] = buf:sub(_tag_start, pos - 1)
         end


@@ 353,7 353,7 @@ function M.HelloReply_decode(buf)
             val, pos = wire.decode_string(buf, pos)
             result.greeting = val
         else
-            pos = wire.skip_field(buf, pos, wt)
+            pos = wire.skip_field(buf, pos, wt, id)
             if _uf == nil then _uf = {} end
             _uf[#_uf + 1] = buf:sub(_tag_start, pos - 1)
         end


@@ 544,7 544,7 @@ function M.Event_decode(buf)
             payload, pos = wire.decode_len(buf, pos)
             result.update_mask = pb.wkt.FieldMask_decode(payload)
         else
-            pos = wire.skip_field(buf, pos, wt)
+            pos = wire.skip_field(buf, pos, wt, id)
             if _uf == nil then _uf = {} end
             _uf[#_uf + 1] = buf:sub(_tag_start, pos - 1)
         end


@@ 635,7 635,7 @@ function M.Address_decode(buf)
             val, pos = wire.decode_string(buf, pos)
             result.apartment = val
         else
-            pos = wire.skip_field(buf, pos, wt)
+            pos = wire.skip_field(buf, pos, wt, id)
             if _uf == nil then _uf = {} end
             _uf[#_uf + 1] = buf:sub(_tag_start, pos - 1)
         end


@@ 915,7 915,7 @@ function M.Person_decode(buf)
                 elseif eid == 2 then
                     _val, _ep = wire.decode_int32(payload, _ep)
                 else
-                    _ep = wire.skip_field(payload, _ep, ewt)
+                    _ep = wire.skip_field(payload, _ep, ewt, eid)
                 end
             end
             map[_key] = _val


@@ 934,7 934,7 @@ function M.Person_decode(buf)
                 elseif eid == 2 then
                     _val, _ep = wire.decode_string(payload, _ep)
                 else
-                    _ep = wire.skip_field(payload, _ep, ewt)
+                    _ep = wire.skip_field(payload, _ep, ewt, eid)
                 end
             end
             map[_key] = _val


@@ 955,12 955,12 @@ function M.Person_decode(buf)
                     _payload, _ep = wire.decode_len(payload, _ep)
                     _val = M.Address_decode(_payload)
                 else
-                    _ep = wire.skip_field(payload, _ep, ewt)
+                    _ep = wire.skip_field(payload, _ep, ewt, eid)
                 end
             end
             map[_key] = _val
         else
-            pos = wire.skip_field(buf, pos, wt)
+            pos = wire.skip_field(buf, pos, wt, id)
             if _uf == nil then _uf = {} end
             _uf[#_uf + 1] = buf:sub(_tag_start, pos - 1)
         end

@@ 2936,7 2936,7 @@ function M.TestAllTypesProto3_decode(buf)
                 elseif eid == 2 then
                     _val, _ep = wire.decode_int32(payload, _ep)
                 else
-                    _ep = wire.skip_field(payload, _ep, ewt)
+                    _ep = wire.skip_field(payload, _ep, ewt, eid)
                 end
             end
             map[_key] = _val


@@ 2955,7 2955,7 @@ function M.TestAllTypesProto3_decode(buf)
                 elseif eid == 2 then
                     _val, _ep = wire.decode_int64(payload, _ep)
                 else
-                    _ep = wire.skip_field(payload, _ep, ewt)
+                    _ep = wire.skip_field(payload, _ep, ewt, eid)
                 end
             end
             for _k in pairs(map) do


@@ 2977,7 2977,7 @@ function M.TestAllTypesProto3_decode(buf)
                 elseif eid == 2 then
                     _val, _ep = wire.decode_uint32(payload, _ep)
                 else
-                    _ep = wire.skip_field(payload, _ep, ewt)
+                    _ep = wire.skip_field(payload, _ep, ewt, eid)
                 end
             end
             map[_key] = _val


@@ 2996,7 2996,7 @@ function M.TestAllTypesProto3_decode(buf)
                 elseif eid == 2 then
                     _val, _ep = wire.decode_uint64(payload, _ep)
                 else
-                    _ep = wire.skip_field(payload, _ep, ewt)
+                    _ep = wire.skip_field(payload, _ep, ewt, eid)
                 end
             end
             for _k in pairs(map) do


@@ 3018,7 3018,7 @@ function M.TestAllTypesProto3_decode(buf)
                 elseif eid == 2 then
                     _val, _ep = wire.decode_sint32(payload, _ep)
                 else
-                    _ep = wire.skip_field(payload, _ep, ewt)
+                    _ep = wire.skip_field(payload, _ep, ewt, eid)
                 end
             end
             map[_key] = _val


@@ 3037,7 3037,7 @@ function M.TestAllTypesProto3_decode(buf)
                 elseif eid == 2 then
                     _val, _ep = wire.decode_sint64(payload, _ep)
                 else
-                    _ep = wire.skip_field(payload, _ep, ewt)
+                    _ep = wire.skip_field(payload, _ep, ewt, eid)
                 end
             end
             for _k in pairs(map) do


@@ 3059,7 3059,7 @@ function M.TestAllTypesProto3_decode(buf)
                 elseif eid == 2 then
                     _val, _ep = wire.decode_fixed32(payload, _ep)
                 else
-                    _ep = wire.skip_field(payload, _ep, ewt)
+                    _ep = wire.skip_field(payload, _ep, ewt, eid)
                 end
             end
             map[_key] = _val


@@ 3078,7 3078,7 @@ function M.TestAllTypesProto3_decode(buf)
                 elseif eid == 2 then
                     _val, _ep = wire.decode_fixed64(payload, _ep)
                 else
-                    _ep = wire.skip_field(payload, _ep, ewt)
+                    _ep = wire.skip_field(payload, _ep, ewt, eid)
                 end
             end
             for _k in pairs(map) do


@@ 3100,7 3100,7 @@ function M.TestAllTypesProto3_decode(buf)
                 elseif eid == 2 then
                     _val, _ep = wire.decode_sfixed32(payload, _ep)
                 else
-                    _ep = wire.skip_field(payload, _ep, ewt)
+                    _ep = wire.skip_field(payload, _ep, ewt, eid)
                 end
             end
             map[_key] = _val


@@ 3119,7 3119,7 @@ function M.TestAllTypesProto3_decode(buf)
                 elseif eid == 2 then
                     _val, _ep = wire.decode_sfixed64(payload, _ep)
                 else
-                    _ep = wire.skip_field(payload, _ep, ewt)
+                    _ep = wire.skip_field(payload, _ep, ewt, eid)
                 end
             end
             for _k in pairs(map) do


@@ 3141,7 3141,7 @@ function M.TestAllTypesProto3_decode(buf)
                 elseif eid == 2 then
                     _val, _ep = wire.decode_float(payload, _ep)
                 else
-                    _ep = wire.skip_field(payload, _ep, ewt)
+                    _ep = wire.skip_field(payload, _ep, ewt, eid)
                 end
             end
             map[_key] = _val


@@ 3160,7 3160,7 @@ function M.TestAllTypesProto3_decode(buf)
                 elseif eid == 2 then
                     _val, _ep = wire.decode_double(payload, _ep)
                 else
-                    _ep = wire.skip_field(payload, _ep, ewt)
+                    _ep = wire.skip_field(payload, _ep, ewt, eid)
                 end
             end
             map[_key] = _val


@@ 3179,7 3179,7 @@ function M.TestAllTypesProto3_decode(buf)
                 elseif eid == 2 then
                     _val, _ep = wire.decode_bool(payload, _ep)
                 else
-                    _ep = wire.skip_field(payload, _ep, ewt)
+                    _ep = wire.skip_field(payload, _ep, ewt, eid)
                 end
             end
             map[_key] = _val


@@ 3198,7 3198,7 @@ function M.TestAllTypesProto3_decode(buf)
                 elseif eid == 2 then
                     _val, _ep = wire.decode_string(payload, _ep)
                 else
-                    _ep = wire.skip_field(payload, _ep, ewt)
+                    _ep = wire.skip_field(payload, _ep, ewt, eid)
                 end
             end
             map[_key] = _val


@@ 3217,7 3217,7 @@ function M.TestAllTypesProto3_decode(buf)
                 elseif eid == 2 then
                     _val, _ep = wire.decode_bytes(payload, _ep)
                 else
-                    _ep = wire.skip_field(payload, _ep, ewt)
+                    _ep = wire.skip_field(payload, _ep, ewt, eid)
                 end
             end
             map[_key] = _val


@@ 3238,7 3238,7 @@ function M.TestAllTypesProto3_decode(buf)
                     _payload, _ep = wire.decode_len(payload, _ep)
                     _val = M.TestAllTypesProto3_NestedMessage_decode(_payload)
                 else
-                    _ep = wire.skip_field(payload, _ep, ewt)
+                    _ep = wire.skip_field(payload, _ep, ewt, eid)
                 end
             end
             map[_key] = _val


@@ 3259,7 3259,7 @@ function M.TestAllTypesProto3_decode(buf)
                     _payload, _ep = wire.decode_len(payload, _ep)
                     _val = M.ForeignMessage_decode(_payload)
                 else
-                    _ep = wire.skip_field(payload, _ep, ewt)
+                    _ep = wire.skip_field(payload, _ep, ewt, eid)
                 end
             end
             map[_key] = _val


@@ 3280,7 3280,7 @@ function M.TestAllTypesProto3_decode(buf)
                     _u, _ep = wire.decode_varint(payload, _ep)
                     _val = wire.varint_to_int32(_u)
                 else
-                    _ep = wire.skip_field(payload, _ep, ewt)
+                    _ep = wire.skip_field(payload, _ep, ewt, eid)
                 end
             end
             map[_key] = _val


@@ 3301,7 3301,7 @@ function M.TestAllTypesProto3_decode(buf)
                     _u, _ep = wire.decode_varint(payload, _ep)
                     _val = wire.varint_to_int32(_u)
                 else
-                    _ep = wire.skip_field(payload, _ep, ewt)
+                    _ep = wire.skip_field(payload, _ep, ewt, eid)
                 end
             end
             map[_key] = _val


@@ 3683,7 3683,7 @@ function M.TestAllTypesProto3_decode(buf)
             val, pos = wire.decode_int32(buf, pos)
             result.Field_name18__ = val
         else
-            pos = wire.skip_field(buf, pos, wt)
+            pos = wire.skip_field(buf, pos, wt, id)
             if _uf == nil then _uf = {} end
             _uf[#_uf + 1] = buf:sub(_tag_start, pos - 1)
         end


@@ 3758,7 3758,7 @@ function M.TestAllTypesProto3_NestedMessage_decode(buf)
                 pb.codec.merge_message(M.TestAllTypesProto3_descriptor, prev, M.TestAllTypesProto3_decode(payload))
             end
         else
-            pos = wire.skip_field(buf, pos, wt)
+            pos = wire.skip_field(buf, pos, wt, id)
             if _uf == nil then _uf = {} end
             _uf[#_uf + 1] = buf:sub(_tag_start, pos - 1)
         end


@@ 3816,7 3816,7 @@ function M.ForeignMessage_decode(buf)
             val, pos = wire.decode_int32(buf, pos)
             result.c = val
         else
-            pos = wire.skip_field(buf, pos, wt)
+            pos = wire.skip_field(buf, pos, wt, id)
             if _uf == nil then _uf = {} end
             _uf[#_uf + 1] = buf:sub(_tag_start, pos - 1)
         end


@@ 3865,7 3865,7 @@ function M.NullHypothesisProto3_decode(buf)
         id, wt, pos = wire.decode_tag(buf, pos)
         if true then
         else
-            pos = wire.skip_field(buf, pos, wt)
+            pos = wire.skip_field(buf, pos, wt, id)
             if _uf == nil then _uf = {} end
             _uf[#_uf + 1] = buf:sub(_tag_start, pos - 1)
         end


@@ 3914,7 3914,7 @@ function M.EnumOnlyProto3_decode(buf)
         id, wt, pos = wire.decode_tag(buf, pos)
         if true then
         else
-            pos = wire.skip_field(buf, pos, wt)
+            pos = wire.skip_field(buf, pos, wt, id)
             if _uf == nil then _uf = {} end
             _uf[#_uf + 1] = buf:sub(_tag_start, pos - 1)
         end

@@ 813,7 813,7 @@ decode_message = function(desc, buf)
         local f = fbi[id]
         if f == nil then
             -- Unknown field: capture verbatim for round-trip.
-            pos = wire.skip_field(buf, pos, wt)
+            pos = wire.skip_field(buf, pos, wt, id)
             if unknown == nil then unknown = {} end
             unknown[#unknown + 1] = buf:sub(tag_start, pos - 1)
         else


@@ 839,7 839,7 @@ decode_message = function(desc, buf)
                     elseif eid == 2 then
                         val, ep = decode_one(f.value, payload, ep)
                     else
-                        ep = wire.skip_field(payload, ep, ewt)
+                        ep = wire.skip_field(payload, ep, ewt, eid)
                     end
                 end
                 if key == nil then key = default_value(f.key) end

@@ 81,7 81,7 @@ local function index_bytes(desc, bytes)
         local tag_start = pos
         local id, wt, npos = wire.decode_tag(bytes, pos)
         local val_start = npos
-        local next_start = wire.skip_field(bytes, npos, wt)
+        local next_start = wire.skip_field(bytes, npos, wt, id)
         n = n + 1
         s_id[n]   = id
         s_tag[n]  = tag_start


@@ 298,7 298,7 @@ local function decode_map_entry(field, bytes, val_start)
                 end
             end
         else
-            p = wire.skip_field(bytes, p, ewt)
+            p = wire.skip_field(bytes, p, ewt, eid)
         end
     end
     if key == nil then

@@ 20,6 20,7 @@
 local ffi      = require('ffi')
 local datetime = require('datetime')
 local pbwkt    = require('pb.wkt')
+local wire     = require('pb.wire')
 
 local M = {}
 


@@ 116,6 117,7 @@ local function new_buf(opts)
         chunks = {}, n = 0,
         single_line = opts.single_line and true or false,
         indent_unit = opts.indent or '  ',
+        print_unknown_fields = opts.print_unknown_fields and true or false,
     }
 end
 


@@ 207,6 209,96 @@ end
 
 local WKT_TEXT  -- forward (filled below)
 
+-- ---------------------------------------------------------------------------
+-- Unknown-field rendering (drives `_Print` conformance tests).
+--
+-- Walks the captured _unknown_fields byte stream (tag+value chunks the
+-- decoder stashed for round-trip) and emits each entry in TextFormat
+-- numeric-field form so the conformance harness's TextFormat::Parser can
+-- round-trip the output back under AllowFieldNumber:
+--   VARINT  -> "<id>: <uint64>"
+--   I64     -> "<id>: 0x<16-hex>"
+--   LEN     -> "<id> { <walk> }" if the payload parses as a sub-message,
+--              else "<id>: <byte-string>"
+--   I32     -> "<id>: 0x<8-hex>"
+--   SGROUP  -> "<id> { <walk> }" (recurses until matching EGROUP)
+local walk_unknown  -- forward; recurses through SGROUP + LEN(message)
+
+walk_unknown = function(buf, raw, pos, lim, depth, end_field_id)
+    while pos <= lim do
+        local id, wt, npos = wire.decode_tag(raw, pos)
+        pos = npos
+        if wt == wire.WIRE_VARINT then
+            local v
+            v, pos = wire.decode_varint(raw, pos)
+            newline(buf, depth)
+            push(buf, tostring(id)); push(buf, ': '); push(buf, int_to_string(v))
+        elseif wt == wire.WIRE_I64 then
+            if pos + 7 > lim then error("truncated I64 in unknown", 0) end
+            local lo = raw:byte(pos)     +
+                       raw:byte(pos + 1) * 0x100 +
+                       raw:byte(pos + 2) * 0x10000 +
+                       raw:byte(pos + 3) * 0x1000000
+            local hi = raw:byte(pos + 4) +
+                       raw:byte(pos + 5) * 0x100 +
+                       raw:byte(pos + 6) * 0x10000 +
+                       raw:byte(pos + 7) * 0x1000000
+            newline(buf, depth)
+            push(buf, tostring(id)); push(buf, ': ')
+            push(buf, string.format('0x%08x%08x', hi, lo))
+            pos = pos + 8
+        elseif wt == wire.WIRE_LEN then
+            local payload
+            payload, pos = wire.decode_len(raw, pos)
+            -- Speculative: render as `<id> { ... }`. Roll back to byte
+            -- form if the payload doesn't parse as a clean sub-message.
+            local n_before = buf.n
+            local ok = pcall(function()
+                emit_block(buf, tostring(id), depth, function(b, d)
+                    walk_unknown(b, payload, 1, #payload, d, nil)
+                end)
+            end)
+            if not ok then
+                buf.n = n_before
+                newline(buf, depth)
+                push(buf, tostring(id)); push(buf, ': ')
+                push(buf, escape_string(payload))
+            end
+        elseif wt == wire.WIRE_I32 then
+            if pos + 3 > lim then error("truncated I32 in unknown", 0) end
+            local v = raw:byte(pos)     +
+                      raw:byte(pos + 1) * 0x100 +
+                      raw:byte(pos + 2) * 0x10000 +
+                      raw:byte(pos + 3) * 0x1000000
+            newline(buf, depth)
+            push(buf, tostring(id)); push(buf, ': ')
+            push(buf, string.format('0x%08x', v))
+            pos = pos + 4
+        elseif wt == wire.WIRE_SGROUP then
+            -- Recurse into the body; the closure mutates `pos` so the
+            -- outer loop continues past the matching EGROUP.
+            emit_block(buf, tostring(id), depth, function(b, d)
+                pos = walk_unknown(b, raw, pos, lim, d, id)
+            end)
+        elseif wt == wire.WIRE_EGROUP then
+            if end_field_id == nil then
+                error("unexpected EGROUP in unknown stream", 0)
+            end
+            if id ~= end_field_id then
+                error(("EGROUP id %d does not match SGROUP id %d"):
+                    format(id, end_field_id), 0)
+            end
+            return pos
+        else
+            error("unknown wire type " .. tostring(wt), 0)
+        end
+    end
+    if end_field_id ~= nil then
+        error("missing EGROUP for field " .. tostring(end_field_id), 0)
+    end
+    return pos
+end
+
 emit_message = function(buf, desc, t, depth)
     -- Use type() rather than == nil so box.NULL (a nil-equal cdata used as
     -- the Value WKT's null_value sentinel) survives the guard.


@@ 228,6 320,15 @@ emit_message = function(buf, desc, t, depth)
             emit_field(buf, f, v, depth)
         end
     end
+    -- Captured unknown bytes go last, mirroring the codec's re-encode
+    -- order. Gated by `opts.print_unknown_fields` to match the protoc
+    -- TextFormat::Printer default (off).
+    if buf.print_unknown_fields then
+        local raw = t._unknown_fields
+        if type(raw) == 'string' and #raw > 0 then
+            walk_unknown(buf, raw, 1, #raw, depth, nil)
+        end
+    end
 end
 
 -- ---------------------------------------------------------------------------

@@ 9,6 9,11 @@ local M = {}
 M.WIRE_VARINT = 0
 M.WIRE_I64    = 1
 M.WIRE_LEN    = 2
+-- Wire 3/4 are proto2 groups. We never emit them, but unknown-field
+-- skip must tolerate them so proto2-shaped payloads round-trip through
+-- a proto3 decoder (conformance suite exercises this).
+M.WIRE_SGROUP = 3
+M.WIRE_EGROUP = 4
 M.WIRE_I32    = 5
 
 local UINT64 = ffi.typeof('uint64_t')


@@ 601,9 606,12 @@ M.TYPE_INFO = {
 
 -- ---------------------------------------------------------------------------
 -- Skip an unknown field (used by decoder when an unrecognized id appears).
--- skip_field(buf, pos, wire_type) -> new_pos
+-- skip_field(buf, pos, wire_type, field_id) -> new_pos
+--
+-- field_id is required for SGROUP (wire 3) so the closing EGROUP can
+-- be matched. Other wire types ignore it.
 -- ---------------------------------------------------------------------------
-local function skip_field(buf, pos, wire_type)
+local function skip_field(buf, pos, wire_type, field_id)
     if wire_type == M.WIRE_VARINT then
         local b = buf:byte(pos)
         if b == nil then error("truncated varint at offset " .. pos, 0) end


@@ 630,6 638,26 @@ local function skip_field(buf, pos, wire_type)
         local np = pos + 4
         if np > #buf + 1 then error("truncated I32 at offset " .. pos, 0) end
         return np
+    elseif wire_type == M.WIRE_SGROUP then
+        -- Read inner tags until the matching EGROUP; recurse on nested
+        -- groups. EGROUP id mismatch is a hard error per spec.
+        if field_id == nil then
+            error("skip_field SGROUP requires field_id", 0)
+        end
+        while true do
+            local iid, iwt
+            iid, iwt, pos = decode_tag(buf, pos)
+            if iwt == M.WIRE_EGROUP then
+                if iid ~= field_id then
+                    error(("EGROUP id %d does not match SGROUP id %d"):
+                        format(iid, field_id), 0)
+                end
+                return pos
+            end
+            pos = skip_field(buf, pos, iwt, iid)
+        end
+    elseif wire_type == M.WIRE_EGROUP then
+        error("unexpected EGROUP for field " .. tostring(field_id), 0)
     end
     error("unknown wire type " .. tostring(wire_type), 0)
 end

@@ 80,7 80,7 @@ local function timestamp_decode(buf)
         elseif id == 2 then
             nanos, pos = wire.decode_int32(buf, pos)
         else
-            pos = wire.skip_field(buf, pos, wt)
+            pos = wire.skip_field(buf, pos, wt, id)
         end
     end
     -- datetime.new validates nanos/seconds ranges. Out-of-spec Timestamps


@@ 139,7 139,7 @@ local function duration_decode(buf)
         elseif id == 2 then
             nanos, pos = wire.decode_int32(buf, pos)
         else
-            pos = wire.skip_field(buf, pos, wt)
+            pos = wire.skip_field(buf, pos, wt, id)
         end
     end
     return {seconds = seconds, nanos = nanos}


@@ 217,7 217,7 @@ for _, spec in ipairs(WRAPPERS) do
             if id == 1 then
                 val, pos = decode(buf, pos)
             else
-                pos = wire.skip_field(buf, pos, wt2)
+                pos = wire.skip_field(buf, pos, wt2, id)
             end
         end
         return val


@@ 374,7 374,7 @@ value_decode = function(buf)
             payload, pos = wire.decode_len(buf, pos)
             result = list_decode(payload)
         else
-            pos = wire.skip_field(buf, pos, wt)
+            pos = wire.skip_field(buf, pos, wt, id)
         end
     end
     return result


@@ 401,12 401,12 @@ struct_decode = function(buf)
                     vbuf, ep = wire.decode_len(payload, ep)
                     val = value_decode(vbuf)
                 else
-                    ep = wire.skip_field(payload, ep, ewt)
+                    ep = wire.skip_field(payload, ep, ewt, eid)
                 end
             end
             result[key] = val
         else
-            pos = wire.skip_field(buf, pos, wt)
+            pos = wire.skip_field(buf, pos, wt, id)
         end
     end
     return result


@@ 423,7 423,7 @@ list_decode = function(buf)
             payload, pos = wire.decode_len(buf, pos)
             result[#result + 1] = value_decode(payload)
         else
-            pos = wire.skip_field(buf, pos, wt)
+            pos = wire.skip_field(buf, pos, wt, id)
         end
     end
     return result


@@ 485,7 485,7 @@ any_decode = function(buf)
         elseif id == 2 then
             value, pos = wire.decode_bytes(buf, pos)
         else
-            pos = wire.skip_field(buf, pos, wt)
+            pos = wire.skip_field(buf, pos, wt, id)
         end
     end
     return {type_url = type_url, value = value}


@@ 571,7 571,7 @@ local function fieldmask_decode(buf)
             s, pos = wire.decode_string(buf, pos)
             result[#result + 1] = s
         else
-            pos = wire.skip_field(buf, pos, wt)
+            pos = wire.skip_field(buf, pos, wt, id)
         end
     end
     return result

@@ 1,26 1,11 @@
 # conformance_test_runner --text_format_failure_list
 #
-# Text-format OUTPUT is now wired through cmd/conformance/core.lua to
-# pb.text.encode (protobuf/JSON input → text output). Input parsing is
-# still deferred — pb.text only encodes — so any test whose payload is
-# text_payload still returns `skipped`.
+# Text-format OUTPUT runs through pb.text.encode (protobuf/JSON input →
+# text output). Group/Repeated unknown-field decode is supported by the
+# SGROUP-recursive `wire.skip_field`, and unknown bytes are rendered in
+# numeric field-ID form when `print_unknown_fields=true`.
 #
-# Remaining expected failures all stem from unknown-field handling:
+# Text-format INPUT is still deferred — pb.text remains encode-only —
+# so any test whose payload is `text_payload` returns `skipped`.
 #
-#   * Group/Repeated *_Drop: our decoder rejects payloads carrying
-#     wire types 3/4 (proto2 groups) and length-mismatched repeated
-#     unknown bytes, so we never reach the encoder. Expected output is
-#     an empty text body, which we'd produce trivially if the decoder
-#     accepted the input. Fixing requires skip_field to tolerate groups.
-#
-#   * *_Print: with `print_unknown_fields: true` the harness expects the
-#     text output to include the original unknown fields. We capture
-#     unknown bytes during decode but pb.text doesn't render them, so
-#     output comes back empty. Fixing requires the text encoder to walk
-#     the captured unknown set.
-Recommended.Proto3.ProtobufInput.GroupUnknownFields_Drop.TextFormatOutput
-Recommended.Proto3.ProtobufInput.GroupUnknownFields_Print.TextFormatOutput
-Recommended.Proto3.ProtobufInput.MessageUnknownFields_Print.TextFormatOutput
-Recommended.Proto3.ProtobufInput.RepeatedUnknownFields_Drop.TextFormatOutput
-Recommended.Proto3.ProtobufInput.RepeatedUnknownFields_Print.TextFormatOutput
-Recommended.Proto3.ProtobufInput.ScalarUnknownFields_Print.TextFormatOutput
+# No expected failures in the proto3 text suite as of the last refresh.

@@ 1215,8 1215,9 @@ local SCALAR_UNKNOWN  = '\xc8\x3e\x7b'                       -- field 1001 varin
 local MESSAGE_UNKNOWN = '\xda\x3e\x02\x08\x6f'               -- field 1003 LEN {1:111}
 local GROUP_UNKNOWN   = '\xe3\x3e\x08\xc1\x02\xe4\x3e'       -- field 1004 SGROUP {a:321} EGROUP
 -- Repeated builds on Group then appends three repeated_int32 entries.
+-- Tag for field 1011 (varint): 1011*8 = 8088 = 24 | (63 << 7) = `\x98\x3f`.
 local REPEATED_UNKNOWN = GROUP_UNKNOWN
-                      .. '\xd8\x3e\x01\xd8\x3e\x02\xd8\x3e\x03'  -- field 1011 varint 1,2,3
+                      .. '\x98\x3f\x01\x98\x3f\x02\x98\x3f\x03'
 
 core_g.test_scalar_unknown_fields_drop = function()
     -- ProtobufInput.ScalarUnknownFields_Drop.TextFormatOutput


@@ 1229,18 1230,14 @@ end
 
 core_g.test_scalar_unknown_fields_print = function()
     -- ProtobufInput.ScalarUnknownFields_Print.TextFormatOutput
-    -- TARGET: text_payload must round-trip to a message containing the
-    -- three unknown fields. Canonical form is numeric IDs, e.g.
-    --   1001: 123\n1002: "hello"\n1006: 1\n
-    -- CURRENT: pb.text doesn't walk _unknown_fields, so output is empty.
-    -- Pin current behavior; flip this assertion when the renderer lands.
+    -- Numeric field-ID form; LEN payload that doesn't parse as a
+    -- sub-message falls back to byte-string rendering ("hello" here).
     local resp = pb_to_text_print_unknowns(SCALAR_UNKNOWN)
     t.assert_not(resp.parse_error, resp.parse_error)
     t.assert_not(resp.serialize_error, resp.serialize_error)
-    t.assert_equals(resp.text_payload, '',
-        'current behavior pins empty output; ' ..
-        'replace with assert_str_contains(...,"1001: 123") when ' ..
-        'pb.text renders captured _unknown_fields')
+    t.assert_str_contains(resp.text_payload, '1001: 123')
+    t.assert_str_contains(resp.text_payload, '1002: "hello"')
+    t.assert_str_contains(resp.text_payload, '1006: 1')
 end
 
 core_g.test_message_unknown_fields_drop = function()


@@ 1252,58 1249,53 @@ end
 
 core_g.test_message_unknown_fields_print = function()
     -- ProtobufInput.MessageUnknownFields_Print.TextFormatOutput
-    -- TARGET text:   1003 {\n  1: 111\n}\n
-    -- CURRENT: pb.text drops _unknown_fields, so output is empty.
+    -- LEN payload parses cleanly as a sub-message ({c:111}), so the
+    -- speculative block-form succeeds: "1003 { 1: 111 }".
     local resp = pb_to_text_print_unknowns(MESSAGE_UNKNOWN)
     t.assert_not(resp.parse_error, resp.parse_error)
-    t.assert_equals(resp.text_payload, '',
-        'replace with target "1003 { 1: 111 }" rendering when ' ..
-        'pb.text grows submessage unknown-field support')
+    t.assert_str_contains(resp.text_payload, '1003 {')
+    t.assert_str_contains(resp.text_payload, '1: 111')
 end
 
 core_g.test_group_unknown_fields_drop = function()
     -- ProtobufInput.GroupUnknownFields_Drop.TextFormatOutput
-    -- Wire types 3/4 (SGROUP/EGROUP) — proto3 must tolerate them as
-    -- unknown groups. Our skip_field currently errors on wire 3, so the
-    -- decoder reports parse_error before reaching the text encoder.
-    -- TARGET: parse_error == nil, text_payload == ''.
+    -- Wire 3/4 are proto2 groups; the proto3 decoder must skip them
+    -- (wire.skip_field recurses on SGROUP until matching EGROUP).
     local resp = pb_to_text(GROUP_UNKNOWN)
-    t.assert_not_equals(resp.parse_error, nil,
-        'current: skip_field rejects SGROUP wire type 3. ' ..
-        'Fix in runtime/pb/wire.lua to recursively skip until matching ' ..
-        'EGROUP, then flip this to assert_not + text_payload == ""')
+    t.assert_not(resp.parse_error, resp.parse_error)
+    t.assert_equals(resp.text_payload, '')
 end
 
 core_g.test_group_unknown_fields_print = function()
     -- ProtobufInput.GroupUnknownFields_Print.TextFormatOutput
-    -- TARGET text:   1004 {\n  1: 321\n}\n  (groups render as submessages)
-    -- CURRENT: blocked by same SGROUP-skip issue as the Drop variant.
+    -- Group bytes are captured verbatim (SGROUP..EGROUP); the renderer
+    -- recurses through them and emits "1004 { 1: 321 }".
     local resp = pb_to_text_print_unknowns(GROUP_UNKNOWN)
-    t.assert_not_equals(resp.parse_error, nil,
-        'blocked on SGROUP support in wire.skip_field; once decoder ' ..
-        'accepts groups and pb.text renders unknowns, expect ' ..
-        'text_payload containing "1004 {" and "1: 321"')
+    t.assert_not(resp.parse_error, resp.parse_error)
+    t.assert_str_contains(resp.text_payload, '1004 {')
+    t.assert_str_contains(resp.text_payload, '1: 321')
 end
 
 core_g.test_repeated_unknown_fields_drop = function()
     -- ProtobufInput.RepeatedUnknownFields_Drop.TextFormatOutput
-    -- Payload prepends a group, so the same SGROUP issue blocks decode.
-    -- TARGET: parse_error == nil, text_payload == ''.
+    -- Payload starts with the same group bytes; after SGROUP-skip the
+    -- repeated_int32 unknowns drop cleanly too.
     local resp = pb_to_text(REPEATED_UNKNOWN)
-    t.assert_not_equals(resp.parse_error, nil,
-        'blocked on SGROUP-skip in wire.lua (group bytes come first)')
+    t.assert_not(resp.parse_error, resp.parse_error)
+    t.assert_equals(resp.text_payload, '')
 end
 
 core_g.test_repeated_unknown_fields_print = function()
     -- ProtobufInput.RepeatedUnknownFields_Print.TextFormatOutput
-    -- TARGET text:
-    --   1004 {\n  1: 321\n}\n1011: 1\n1011: 2\n1011: 3\n
-    -- CURRENT: blocked by SGROUP-skip, then by unknown-field rendering.
+    -- Group bytes followed by three repeated-int32 entries. Each varint
+    -- becomes its own "<id>: <value>" line.
     local resp = pb_to_text_print_unknowns(REPEATED_UNKNOWN)
-    t.assert_not_equals(resp.parse_error, nil,
-        'two-stage fix: (1) accept SGROUP in wire.skip_field, ' ..
-        '(2) render captured _unknown_fields from pb.text. ' ..
-        'Then assert_str_contains for "1011: 1", "1011: 2", "1011: 3"')
+    t.assert_not(resp.parse_error, resp.parse_error)
+    t.assert_str_contains(resp.text_payload, '1004 {')
+    t.assert_str_contains(resp.text_payload, '1: 321')
+    t.assert_str_contains(resp.text_payload, '1011: 1')
+    t.assert_str_contains(resp.text_payload, '1011: 2')
+    t.assert_str_contains(resp.text_payload, '1011: 3')
 end
 
 -- ---------------------------------------------------------------------------