## Problem
`workspace_fingerprint(path)` hashes the raw path string without
canonicalization. Two equivalent paths (e.g. `/tmp/foo` vs
`/private/tmp/foo` on macOS) produce different fingerprints and
therefore different session stores. #150 fixed the test-side symptom;
this fixes the underlying product contract.
## Discovery path
#150 fix (canonicalize in test) was a workaround. Q's ack on #150
surfaced the deeper gap: the function itself is still fragile for
any caller passing a non-canonical path:
1. Embedded callers with a raw `--data-dir` path
2. Programmatic `SessionStore::from_cwd(user_path)` calls
3. NixOS store paths, Docker bind mounts, case-insensitive normalization
The REPL's default flow happens to work because `env::current_dir()`
returns canonical paths on macOS. But any caller passing a raw path
risks silent session-store divergence.
## Fix
Canonicalize inside `SessionStore::from_cwd()` and `from_data_dir()`
before computing the fingerprint. Kept `workspace_fingerprint()` itself
as a pure function for determinism — canonicalization is the entry
point's responsibility.
```rust
let canonical_cwd = fs::canonicalize(cwd).unwrap_or_else(|_| cwd.to_path_buf());
let sessions_root = canonical_cwd.join(".claw").join("sessions").join(workspace_fingerprint(&canonical_cwd));
```
Falls back to the raw path if canonicalize fails (directory doesn't
exist yet).
## Test-side updates
Three legacy-session tests expected the non-canonical base path to
match the store's workspace_root. Updated them to canonicalize
`base` after creation — same defensive pattern as #150, now
explicit across all three tests.
## Regression test
Added `session_store_from_cwd_canonicalizes_equivalent_paths` that
creates two stores from equivalent paths (raw vs canonical) and
asserts they resolve to the same sessions_dir.
## Verification
- `cargo test -p runtime session_store_` — 9/9 pass
- `cargo test --workspace` — all green, no FAILED markers
- No behavior change for existing users (REPL default flow already
used canonical paths)
## Backward compatibility
Users on macOS who always went through `env::current_dir()`:
no hash change, sessions resume identically.
Users who ever called with a non-canonical path: hash would change,
but those sessions were already broken (couldn't be resumed from a
canonical-path cwd). Net improvement.
Closes ROADMAP #151.
7bc66e86e8