From 786fe39b24032f832b6a2410a19b53b4618cd8e9 Mon Sep 17 00:00:00 2001
From: highlander <highlander@keepkey.com>
Date: Thu, 17 Sep 2026 19:22:01 -0600
Subject: [PATCH] feat(erc7730): compile nested arrays and NFT collections

---
 keepkeylib/erc7730_compiler.py | 50 ++++++++++++++++++++++++++--------
 tests/test_erc7730_compiler.py | 25 +++++++++++++++++
 2 files changed, 64 insertions(+), 11 deletions(-)

diff --git a/keepkeylib/erc7730_compiler.py b/keepkeylib/erc7730_compiler.py
index 6fef8bdd..b62cdb70 100644
--- a/keepkeylib/erc7730_compiler.py
+++ b/keepkeylib/erc7730_compiler.py
@@ -638,6 +638,31 @@ def intern_path(steps):
                     literals.append((9, _u16(len(references)) + b"".join(
                         _u16(index) for index in references)))
                     arguments.append((22, 2, len(literals) - 1))
+            elif kind == 4:
+                collection = params.get("collectionPath")
+                if collection is None:
+                    collection = params.get("collection")
+                collection = descriptor_value(collection)
+                if isinstance(collection, str) and collection.startswith("0x"):
+                    literals.append((5, _hex_address(collection)))
+                    collection_path = intern_path(
+                        (("literal", len(literals) - 1),))
+                elif isinstance(collection, str):
+                    collection_path = intern_path(_resolve_path(root, collection))
+                else:
+                    raise ValueError("nftName requires collection or collectionPath")
+                arguments.append((3, 1, collection_path))
+                chain = params.get("chainIdPath", params.get("chainId"))
+                if chain is not None:
+                    chain = descriptor_value(chain)
+                    if isinstance(chain, int):
+                        literals.append((7, _unsigned_literal(chain)))
+                        arguments.append((11, 2, len(literals) - 1))
+                    elif isinstance(chain, str):
+                        arguments.append((11, 1,
+                                          intern_path(_resolve_path(root, chain))))
+                    else:
+                        raise ValueError("invalid nftName chainId")
             elif kind == 5:
                 encoding = params.get("encoding", "timestamp")
                 arguments.append((9, 3, string_index[encoding]))
@@ -704,21 +729,24 @@ def intern_path(steps):
                                    value_path, len(literals) - 1))
             all_positions = [i for i, step in enumerate(steps)
                              if step[0] == 2]
-            if len(all_positions) > 1:
-                raise ValueError("nested array iteration requires a field group")
             if all_positions:
-                prefix = steps[:all_positions[0]]
-                array_path = intern_path(prefix)
-                begin = len(displays)
-                displays.append([7, array_path, condition, 0])
+                begins = []
+                for position in all_positions:
+                    array_path = intern_path(steps[:position + 1])
+                    begin = len(displays)
+                    begins.append(begin)
+                    displays.append([7, array_path, condition, 0])
                 displays.append([4, string_index[field["label"]],
                                  formatter_index, ABSENT])
-                end = len(displays)
                 separator = field.get("separator")
-                displays.append([8, begin,
-                                 string_index[separator] if separator else ABSENT,
-                                 ABSENT])
-                displays[begin][3] = end
+                for depth, begin in enumerate(reversed(begins)):
+                    end = len(displays)
+                    displays.append([
+                        8, begin,
+                        (string_index[separator]
+                         if separator and depth == len(begins) - 1 else ABSENT),
+                        ABSENT])
+                    displays[begin][3] = end
             else:
                 displays.append([4, string_index[field["label"]],
                                  formatter_index, condition])
diff --git a/tests/test_erc7730_compiler.py b/tests/test_erc7730_compiler.py
index 1a10aadb..f108eff0 100644
--- a/tests/test_erc7730_compiler.py
+++ b/tests/test_erc7730_compiler.py
@@ -244,6 +244,31 @@ def test_compiles_array_iteration_separator_and_optional_visibility():
             subprocess.check_call([validator, output.name])
 
 
+def test_compiles_recursive_array_iteration_frames():
+    descriptor = {"display": {"formats": {
+        "matrix(uint256[][] values)": {
+            "intent": "Review matrix",
+            "fields": [{"path": "values.[].[]", "label": "Value",
+                        "format": "raw", "separator": "Next row"}],
+        }
+    }}}
+    compiled = compile_calldata(
+        descriptor, "matrix(uint256[][] values)", 1,
+        "0x1111111111111111111111111111111111111111")
+    display = _sections(compiled)[7]
+    count = int.from_bytes(display[:2], "big")
+    instructions = [display[2 + i * 8:10 + i * 8] for i in range(count)]
+    assert [item[0] for item in instructions] == [1, 7, 7, 4, 8, 8, 10]
+    assert int.from_bytes(instructions[1][6:8], "big") == 5
+    assert int.from_bytes(instructions[2][6:8], "big") == 4
+    validator = os.environ.get("ERC7730_FIRMWARE_VALIDATOR")
+    if validator:
+        with tempfile.NamedTemporaryFile() as output:
+            output.write(compiled)
+            output.flush()
+            subprocess.check_call([validator, output.name])
+
+
 def test_compiles_typed_if_not_in_and_must_match_conditions():
     descriptor = {"display": {"formats": {
         "guard(uint256 mode,address recipient)": {