fix: skip $$-prefixed inputs in cache signature computation

[bigcat88]

Frontend now sends $$node-text-preview in node inputs with values that change between runs (e.g. execution timing). The cache signature was computed over all input keys, causing cache misses on identical re-runs.

Skip $$-prefixed keys in get_immediate_node_signature - these are frontend metadata already ignored during execution.

[coderabbitai]

📝 Walkthrough

Walkthrough

The get_immediate_node_signature function in comfy_execution/caching.py has been modified to skip input keys that begin with "$$" during signature construction. This change filters out internal or annotation-marked inputs from both the ancestor-derived and direct inputs portions of the resulting node signature. The modification adds two lines and does not alter any other logic or control flow in the function.

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately describes the main change: skipping $$-prefixed inputs in cache signature computation to fix cache invalidation issues.
Description check	✅ Passed	The pull request description clearly explains the problem (cache misses due to changing $$-prefixed inputs) and the solution (skip these keys in signature computation).

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[coderabbitai]

🧹 Nitpick comments (1)

comfy_execution/caching.py (1)

119-128: LGTM — fix is correct and minimal.

Skipping $$-prefixed keys in the signature loop directly addresses the cache-miss regression. Because these keys carry metadata strings (not link tuples), is_link() returns False for them in get_ordered_ancestry_internal, so no parallel change is needed there — they were already a no-op in ancestry traversal.

One minor thing worth being aware of: if the frontend ever sends a $$-prefixed input that is a link (unlikely per the current contract, but possible in future), get_ordered_ancestry_internal would still walk it into order_mapping, while the signature loop would silently skip it. That asymmetry could produce incorrect cache hits in that hypothetical case. A defensive guard in get_ordered_ancestry_internal would future-proof this:

🛡️ Optional defensive guard for future-proofing

     input_keys = sorted(inputs.keys())
     for key in input_keys:
+        if key.startswith("$$"):
+            continue
         if is_link(inputs[key]):

🤖 Prompt for AI Agents

Verify each finding against the current code and only fix it if needed.

In `@comfy_execution/caching.py` around lines 119 - 128, Add a defensive guard to
get_ordered_ancestry_internal so it ignores inputs whose keys start with "$$"
before treating them as links: check the input key prefix early in the loop (the
same "$$" check used in the signature builder) and skip processing/adding to
ancestor/order mappings for those keys; this keeps behavior symmetric with the
signature construction and prevents future mismatches if a $$-prefixed value
ever appears as a link, while still using is_link(...) for normal keys.

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Nitpick comments:
In `@comfy_execution/caching.py`:
- Around line 119-128: Add a defensive guard to get_ordered_ancestry_internal so
it ignores inputs whose keys start with "$$" before treating them as links:
check the input key prefix early in the loop (the same "$$" check used in the
signature builder) and skip processing/adding to ancestor/order mappings for
those keys; this keeps behavior symmetric with the signature construction and
prevents future mismatches if a $$-prefixed value ever appears as a link, while
still using is_link(...) for normal keys.

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ℹ️ Review info

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📥 Commits

Reviewing files that changed from the base of the PR and between 3ebe1ac and 6505622.

📒 Files selected for processing (1)

• comfy_execution/caching.py