From a38c5bb0850a0a28cb1371a8caa0dfa7f6505a32 Mon Sep 17 00:00:00 2001
From: jan <jan@orange.mpxd.net>
Date: Mon, 9 Mar 2026 01:15:42 -0700
Subject: [PATCH] [ports2data] deal with cycles better

---
 masque/utils/ports2data.py | 29 +++++++++++++++++++----------
 1 file changed, 19 insertions(+), 10 deletions(-)

diff --git a/masque/utils/ports2data.py b/masque/utils/ports2data.py
index b97b41e..889425e 100644
--- a/masque/utils/ports2data.py
+++ b/masque/utils/ports2data.py
@@ -57,11 +57,9 @@ def data_to_ports(
         name: str | None = None,     # Note: name optional, but arg order different from read(postprocess=)
         max_depth: int = 0,
         skip_subcells: bool = True,
-        # TODO missing ok?
+        visited: set[int] | None = None,
         ) -> Pattern:
     """
-    # TODO fixup documentation in ports2data
-    # TODO move to utils.file?
     Examine `pattern` for labels specifying port info, and use that info
       to fill out its `ports` attribute.
 
@@ -70,18 +68,28 @@ def data_to_ports(
 
     Args:
         layers: Search for labels on all the given layers.
+        library: Mapping from pattern names to patterns.
         pattern: Pattern object to scan for labels.
-        max_depth: Maximum hierarcy depth to search. Default 999_999.
+        name: Name of the pattern object.
+        max_depth: Maximum hierarcy depth to search. Default 0.
             Reduce this to 0 to avoid ever searching subcells.
         skip_subcells: If port labels are found at a given hierarcy level,
             do not continue searching at deeper levels. This allows subcells
             to contain their own port info without interfering with supercells'
             port data.
             Default True.
+        visited: Set of object IDs which have already been processed.
 
     Returns:
         The updated `pattern`. Port labels are not removed.
     """
+    if visited is None:
+        visited = set()
+
+    if id(pattern) in visited:
+        return pattern
+    visited.add(id(pattern))
+
     if pattern.ports:
         logger.warning(f'Pattern {name if name else pattern} already had ports, skipping data_to_ports')
         return pattern
@@ -99,12 +107,13 @@ def data_to_ports(
         if target is None:
             continue
         pp = data_to_ports(
-            layers=layers,
-            library=library,
-            pattern=library[target],
-            name=target,
-            max_depth=max_depth - 1,
-            skip_subcells=skip_subcells,
+            layers = layers,
+            library = library,
+            pattern = library[target],
+            name = target,
+            max_depth = max_depth - 1,
+            skip_subcells = skip_subcells,
+            visited = visited,
             )
         found_ports |= bool(pp.ports)