shaheeramjad opened a new issue, #37422:
URL: https://github.com/apache/beam/issues/37422
### What would you like to happen?
Currently, many exception handlers throughout the Python SDK re-raise
exceptions without using `raise ... from`, which loses the original traceback
context. This makes debugging significantly harder because developers can't see
the root cause when exceptions are wrapped.
**Example Problem:**
```python
# Current code (loses context)
try:
connection = self._engine.connect()
result = connection.execute(text(query))
except Exception as e:
raise RuntimeError(f"Database operation failed: {e}")
```
When this fails, you only see:
```
RuntimeError: Database operation failed: connection timeout
```
But you don't see the original `ConnectionTimeoutError` with its full
traceback.
**Desired Solution:**
```python
# With exception chaining (preserves context)
try:
connection = self._engine.connect()
result = connection.execute(text(query))
except Exception as e:
raise RuntimeError(f"Database operation failed: {e}") from e
```
Now you see:
```
RuntimeError: Database operation failed: connection timeout
The above exception was the direct cause of the following exception:
ConnectionTimeoutError: Failed to connect within 30 seconds
[full original traceback here]
```
I would like to systematically add exception chaining throughout the
codebase. This involves:
1. **Identifying all exception re-raises** - Find all places where
exceptions are caught and re-raised
2. **Adding `from e` clause** - Update `raise NewException(...)` to `raise
NewException(...) from e`
3. **Enabling pylint warning** - Enable the `raise-missing-from` warning in
`.pylintrc` (currently disabled with TODO)
4. **Adding tests** - Ensure exception chains are preserved in error
scenarios
5. **Incremental approach** - Start with high-traffic modules (transforms,
runners, IO)
This enhancement will significantly improve debuggability by preserving the
full exception context, making it easier to identify root causes of failures in
production pipelines.
**Note:** This is already tracked in `.pylintrc` line 139:
```python
raise-missing-from, #TODO(https://github.com/apache/beam/issues/21169)
Enable and fix warnings
```
### Issue Priority
Priority: 3 (P3 - Code quality improvement)
### Issue Components
- Component: Python SDK
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