[alex-clickhouse]

What

ClaudeBackend.validate_resume_target now builds the history directory name with the same rule as the Claude CLI. Before Nerve resumes a stored SDK session, it checks that ~/.claude/projects/<encoded-cwd>/<session-id>.jsonl exists. The check encoded the cwd by replacing only / with -.

Why

The CLI replaces every character outside [a-zA-Z0-9] with -. For a workspace path that contains another character, for example _ or ., the check looks in a directory that does not exist and returns False. The engine then drops the stored session ID and starts a new conversation on each client rebuild: model change, dead client, restart. Seen with a workspace at /tmp/<name>_/ws: the CLI wrote to -tmp-<name>--ws, and the check looked in -tmp-<name>_-ws. Paths such as ~/nerve-workspace are not affected.

How

The rule comes from the CLI bundled with claude-agent-sdk 0.2.161:

function k(e){return e.replace(/[^a-zA-Z0-9]/g,"-")}
function AR(e){let n=k(e);if(n.length<=200)return n;return`${n.slice(0,200)}-${hash(e)}`}

• _encode_project_dir() applies the same regex. The JS regex works on UTF-16 code units, so a character outside the Basic Multilingual Plane becomes --. node gives the same output for the test inputs.
• When the encoded name is longer than 200 characters, the CLI cuts it and adds -<hash>. When the CLI looks up a session, it lists the projects directory and matches on the cut name plus -. _long_project_dir_names() does the same, so Nerve does not compute the hash. A missing projects directory gives False, the same as for a short name.
• The realpath-first, unresolved-path-second order and the fail-open except do not change.

Tests

tests/test_engine.py::TestValidateResumeTarget:

• New: a path with _ and . (mocked and on a real filesystem), a character outside the BMP, a name over 200 characters with a suffixed directory, a sibling that does not match, and a missing projects directory.
• The three symlink tests built the expected directory name with replace("/", "-"). pytest's tmp_path contains _, so they now use the CLI rule.
• Against the old implementation, 6 of the 13 tests fail. With the change, all pass.

Full backend suite: 5753 passed, 38 skipped.

🤖 Generated with Claude Code