## Summary
While fixing #16467 (IterationItem crash on `@` in user-defined output
keys), an audit of `agent/**/*.py` revealed **three additional sites**
with the same vulnerability. This PR hardens all of them with
`maxsplit=1` and adds regression tests.
This is **defense-in-depth hardening**, not a behavior change. The
current `variable_ref_patt` regex constrains `var_nm` to
`[A-Za-z0-9_.-]+`, so single-`@` templates resolve exactly as before.
The `maxsplit=1` only kicks in if the trailing side itself contains `@`
— currently unreachable from the public DSL surface, but trivially
exploitable the moment a user-defined output key happens to contain `@`
(e.g. `user@email`) or the regex is ever relaxed.
> **Note on issue scope**: The primary fix for #16467 (the
`list_tenant_added_models` `ValueError` crash on `@` in model names) is
in PR #16468. This PR is a **follow-up hardening sweep** of the same
vulnerability class found in `agent/` during that audit; it does not
duplicate or replace #16468.
## Sites hardened
| File | Line | Method |
|------|------|--------|
| `agent/canvas.py` | 206 | `Graph.get_variable_value` |
| `agent/canvas.py` | 256 | `Graph.set_variable_value` |
| `agent/component/base.py` | 533 |
`ComponentBase.get_input_elements_from_text` |
| `agent/component/iterationitem.py` | 88 |
`IterationItem.output_collation` |
All now use `split("@", 1)` with an inline comment explaining the
rationale. The trailing side keeps any embedded `@`.
## Sites already safe (audited but left alone)
| File | Reason safe |
|------|------------|
| `agent/canvas.py:708` (`is_reff`) | Pre-checks `len(arr) != 2` |
| `agent/component/categorize.py` | Uses `rsplit` |
| `agent/component/iteration.py` | Pre-validates via regex |
| Other call sites | `rsplit` or regex pre-validation |
## Regression tests
9 new tests across 2 files, all `pytest.mark.p2`:
| File | Tests |
|------|-------|
| `test/unit_test/agent/test_canvas_at_split.py` | 6 —
`get_variable_value`, `set_variable_value`, round-trip, single-`@`,
missing-component |
| `test/unit_test/agent/component/test_iterationitem_at_split.py` | 3 —
`output_collation` with `@` in var, single-`@`, non-matching cid |
Each test was **verified to fail with `ValueError: too many values to
unpack (expected 2)`** when the corresponding fix is temporarily
reverted, confirming the tests actually catch the bug rather than just
exercising the happy path.
## Test results
```
9 passed in 0.04s
```
Full agent unit suite also clean (38 passed, 3 skipped; 6 unrelated
pre-existing collection errors from missing `peewee`/`requests` in local
venv — not caused by this PR).
## Related
- Issue: #16467
- Primary fix PR: #16468 (closes the issue)
- This PR: defense-in-depth follow-up, intentionally non-blocking on
#16467
---------
Co-authored-by: skbs-eng <skbs-eng@users.noreply.github.com>
Two small fixes:
1. **iterationitem.py line 72**: Typo "interationitem" → "iterationitem"
(missing 't'). The component name check never matched IterationItem
components.
2. **raptor.py line 94**: Error message "Embedding error: " had a
trailing colon with no details. Changed to "Embedding error: empty
embeddings returned".
### What problem does this PR solve?
Add mechanism to check cancellation in Agent.
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
### What problem does this PR solve?
#9082#6365
<u> **WARNING: it's not compatible with the older version of `Agent`
module, which means that `Agent` from older versions can not work
anymore.**</u>
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
