feat: support training with JSON string tool arguments (#3136)

* feat: support training with JSON string tool arguments; fix PyArrow data type inconsistent error

* feat: raise error for tool call arguments decode

* Add test_chat_templates_tool_call_string_arguments.py

Add test for string arguments

* fix: change to correct qwen3 tokenizer

* fix: update docs to clarify arguments json

* chore: lint

* fix: duplicate

* chore: revert

* feat: add error to faq

* fix: remove duplicate fixture

---------

Co-authored-by: caoqinping <caoqinping@lixiang.com>
Co-authored-by: gamersover-blog <1611885128@qq.com>
Co-authored-by: NanoCode012 <nano@axolotl.ai>

docs/dataset-formats/conversation.qmd

@@ -212,6 +212,14 @@ Instead of passing `tools` via the system prompt, an alternative method would be
 Tools need to follow [JSON schema](https://json-schema.org/learn/getting-started-step-by-step).
 :::
 
+::: {.callout-warning}
+If you have tool arguments with same name but different dtypes (like `"time": string` and `"time": number`), please save `arguments: ` as JSON string to prevent `datasets` from having casting issues.
+
+```
+"arguments": "{\"...\": \"...\"}"
+```
+:::
+
 Example config for Llama4:
 ```yaml
 chat_template: llama4

docs/faq.qmd

@@ -140,3 +140,7 @@ description: Frequently asked questions
 **Q: `ValueError("Backward pass should have cleared tracker of all tensors")`
 
 > A: This may happen due to edge cases in using the modern OffloadActivations context manager for CUDA streams. If you encounter this error, you may have success using the naive implementation with `offload_activations: legacy` in your YAML.
+
+**Q: `Error parsing tool_calls arguments as JSON.`
+
+> A: There is an error parsing string arguments to a dict. Please check your dataset and the error message for more details.