Caspar Broekhuizen 15d558ff16 fix(core): resolve mermaid node id collisions when special chars are used (#32857) ...

### Description

* Replace the Mermaid graph node label escaping logic
(`_escape_node_label`) with `_to_safe_id`, which converts a string into
a unique, Mermaid-compatible node id. Ensures nodes with special
characters always render correctly.

**Before**
* Invalid characters (e.g. `开`) replaced with `_`. Causes collisions
between nodes with names that are the same length and contain all
non-safe characters:
```python
_escape_node_label("开") # '_'
_escape_node_label("始") # '_'  same as above, but different character passed in. not a unique mapping.
```

**After**
```python
_to_safe_id("开") # \5f00
_to_safe_id("始") # \59cb  unique!
```

### Tests
* Rename `test_graph_mermaid_escape_node_label()` to
`test_graph_mermaid_to_safe_id()` and update function logic to use
`_to_safe_id`
* Add `test_graph_mermaid_special_chars()`

### Issue

Fixes langchain-ai/langgraph#6036

2025-09-11 14:15:17 -07:00

..

benchmarks

core: make ruff rule PLW1510 unfixable (#31868)

2025-07-07 10:28:30 -04:00

integration_tests

core: Add ruff rules for PIE (#26939)

2024-09-27 12:08:35 -04:00

unit_tests

fix(core): resolve mermaid node id collisions when special chars are used (#32857)

2025-09-11 14:15:17 -07:00

__init__.py

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