stemedb/ai-lookup/patterns/error-handling.md
jml 9bfa626203 docs: reorganize documentation structure for clarity
Major documentation restructure to improve discoverability and reduce duplication.

## Changes

**Deleted (Archived/Consolidated)**:
- Removed duplicate getting started guides
- Archived outdated planning documents
- Consolidated corpus and configuration docs
- Removed obsolete vision/spec files (superseded by vision.md)
- Cleaned up scrapyard and old PDFs

**New Structure**:
- docs/about/ - Project overview and introduction
- docs/guides/ - User guides (moved from root)
- docs/specs/ - Technical specifications
- docs/sdk/ - SDK documentation (Go)
- docs/references/ - API references
- docs/archive/ - Archived historical docs
- applications/aphoria/docs/advanced/ - Advanced topics
- applications/aphoria/docs/reference/ - CLI reference
- applications/aphoria/docs/archive/ - Archived aphoria docs

**Updated**:
- README.md - New root README with clear navigation
- CONTRIBUTING.md - Contribution guidelines
- CLAUDE.md - Updated paths to new structure
- roadmap.md - Added recent completions

## Files Changed
- 57 files changed
- 1,977 insertions(+)
- 961 deletions(-)

**Net change**: +1,016 lines (added CONTRIBUTING.md, README.md, reorganized content)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
2026-02-11 07:33:40 +00:00

70 lines
2.1 KiB
Markdown

# Error Handling Pattern
**Last Updated:** 2026-01-31
**Confidence:** High
## Summary
StemeDB uses `thiserror` for library errors with context chains. No panics in production code. All fallible operations return `Result<T, E>`.
**Key Facts:**
- Library code: `thiserror` for custom error types — ALL error enums MUST use `#[derive(thiserror::Error)]`
- Binary code: `anyhow` for error chaining
- Never use `unwrap()`, `expect()`, `panic!()` in production
- Add context with `.context("what we were doing")?`
- NEVER use manual `impl Display` + `impl Error` for error types — use thiserror derives instead
**Error types in workspace (all use thiserror):**
- `stemedb-core/src/serde.rs``SerdeError`
- `stemedb-wal/src/error.rs``QuarantineError`
- `stemedb-storage/src/error.rs``StorageError`
- `stemedb-ingest/src/error.rs``IngestError`
- `stemedb-query/src/error.rs``QueryError`
- `stemedb-api/src/error.rs``ApiError`
## The Pattern
```rust
use thiserror::Error;
#[derive(Debug, Error)]
pub enum StemeError {
#[error("assertion not found: {0:?}")]
NotFound(Hash),
#[error("invalid signature for agent {agent:?}")]
InvalidSignature { agent: AgentId },
#[error("storage error: {0}")]
Storage(String),
#[error("serialization error: {0}")]
Serialization(String),
}
// Usage with context
fn load_assertion(&self, hash: &Hash) -> Result<Assertion, StemeError> {
let bytes = self.store
.get(hash.as_bytes())
.context("failed to read assertion from store")?
.ok_or(StemeError::NotFound(*hash))?;
rkyv::from_bytes(&bytes)
.map_err(|e| StemeError::Serialization(e.to_string()))
}
```
## Error Categories
| Type | Description | Example |
|------|-------------|---------|
| `NotFound` | Data doesn't exist | Missing assertion |
| `InvalidSignature` | Crypto verification failed | Tampered assertion |
| `Storage` | Underlying KV error | Disk full |
| `Serialization` | Encode/decode failed | Corrupt data |
## Related Topics
- [Rust Guidelines](../../.claude/guides/backend/rust-guidelines.md)
- [Coding Guidelines](../../../.claude/guides/coding-guidelines.md)