feat(blocks): key normalization and weight-string parsing

src/blocks.py

@@ -0,0 +1,36 @@
+"""
+Pure logic for block-wise LoRA weighting (PM Block Selector + model block nodes).
+
+No ComfyUI or intra-package imports so this module is unit-testable in isolation.
+"""
+import logging
+import re
+from typing import Any, Dict, Iterable, List, Optional
+
+
+def normalize_key(key: Any) -> str:
+    """Return the string form of a LoRA layer key (ComfyUI keys may be tuples)."""
+    if isinstance(key, tuple):
+        return str(key[0])
+    return str(key)
+
+
+def parse_weight_list(s: Optional[str], default: float = 1.0) -> List[float]:
+    """Parse a comma-separated per-group weight string into a list of floats.
+
+    Empty or unparseable tokens fall back to ``default``. ``None`` yields ``[]``.
+    """
+    if s is None:
+        return []
+    out: List[float] = []
+    for tok in str(s).split(","):
+        tok = tok.strip()
+        if tok == "":
+            out.append(default)
+            continue
+        try:
+            out.append(float(tok))
+        except ValueError:
+            logging.warning(f"[PM Blocks] Could not parse weight '{tok}', using {default}")
+            out.append(default)
+    return out

tests/test_blocks.py

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+from blocks import normalize_key, parse_weight_list
+
+
+class TestNormalizeKey:
+    def test_string_key_unchanged(self):
+        assert normalize_key("diffusion_model.blocks.0.attn.wq.weight") == \
+            "diffusion_model.blocks.0.attn.wq.weight"
+
+    def test_tuple_key_uses_first_element(self):
+        assert normalize_key(("diffusion_model.single_blocks.0.linear1.weight", (0, 0, 9))) == \
+            "diffusion_model.single_blocks.0.linear1.weight"
+
+
+class TestParseWeightList:
+    def test_simple_list(self):
+        assert parse_weight_list("1,1,0.8,0.5,0") == [1.0, 1.0, 0.8, 0.5, 0.0]
+
+    def test_whitespace_tolerated(self):
+        assert parse_weight_list(" 1.0 , 0.5 ") == [1.0, 0.5]
+
+    def test_empty_token_uses_default(self):
+        assert parse_weight_list("1,,0.5", default=1.0) == [1.0, 1.0, 0.5]
+
+    def test_empty_string_returns_single_default(self):
+        assert parse_weight_list("", default=1.0) == [1.0]
+
+    def test_invalid_token_uses_default(self):
+        assert parse_weight_list("1,abc,0.5", default=1.0) == [1.0, 1.0, 0.5]
+
+    def test_none_returns_empty(self):
+        assert parse_weight_list(None) == []