fix(F8): session schema versioning with migration hook + corruption diag - #83
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Track F-HIGH #8 from ROADMAP.md. ## Problem `load_session` (`storage.rs:98-104`) deserialized raw JSON with no schema versioning. Two pain points: 1. **Corrupted files** (truncated mid-write before atomic save shipped, or external mutation) surfaced as `expected ',' or '}' at line N column M` with no file path. A user with many sessions had to grep to figure out which one was broken. 2. **No migration path** for future schema bumps. Field additions so far used `#[serde(default)]` so they migrated transparently, but a real shape change (renaming a field, restructuring `tree.entries`) would silently corrupt old sessions on first load with no way to detect. ## Fix `Session` gains `pub schema_version: u32` with `#[serde(default)]` so pre-F8 files load with `schema_version = 0`. `Session::new` sets it to the current `SCHEMA_VERSION` constant (initial value: 1 — first versioned schema). `load_session` now: 1. Wraps the parse error with `path.display()` context so the user sees `failed to parse <path>: <serde error>`. 2. After successful deserialize, compares `session.schema_version` against `SCHEMA_VERSION`: - Lower → call `migrate_session(&mut session)` then bump. - Equal → no-op. - Higher (file from newer dirge) → warn via tracing but still load. Most fields default-migrate via serde; only truly new fields get default values. `migrate_session` is a single function with version gates ready for future schema work. The v0 → v1 step is a no-op (current schema is structurally identical to pre-F8; only the field introduction marks the version). ## Tests Two new tests in `session::storage::tests`: - `load_session_migrates_pre_f8_files`: writes a minimal pre-F8 session JSON (no schema_version field) to disk, loads it, asserts schema_version is bumped to SCHEMA_VERSION and the data is intact. - `load_session_corrupted_file_includes_path_in_error`: writes a truncated JSON, asserts the error mentions the path so the user can grep `dirge` logs and identify the broken file. 664 pass (was 662). All build profiles clean.
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…iag (dirge-code#83) Track F-HIGH dirge-code#8 from ROADMAP.md. ## Problem `load_session` (`storage.rs:98-104`) deserialized raw JSON with no schema versioning. Two pain points: 1. **Corrupted files** (truncated mid-write before atomic save shipped, or external mutation) surfaced as `expected ',' or '}' at line N column M` with no file path. A user with many sessions had to grep to figure out which one was broken. 2. **No migration path** for future schema bumps. Field additions so far used `#[serde(default)]` so they migrated transparently, but a real shape change (renaming a field, restructuring `tree.entries`) would silently corrupt old sessions on first load with no way to detect. ## Fix `Session` gains `pub schema_version: u32` with `#[serde(default)]` so pre-F8 files load with `schema_version = 0`. `Session::new` sets it to the current `SCHEMA_VERSION` constant (initial value: 1 — first versioned schema). `load_session` now: 1. Wraps the parse error with `path.display()` context so the user sees `failed to parse <path>: <serde error>`. 2. After successful deserialize, compares `session.schema_version` against `SCHEMA_VERSION`: - Lower → call `migrate_session(&mut session)` then bump. - Equal → no-op. - Higher (file from newer dirge) → warn via tracing but still load. Most fields default-migrate via serde; only truly new fields get default values. `migrate_session` is a single function with version gates ready for future schema work. The v0 → v1 step is a no-op (current schema is structurally identical to pre-F8; only the field introduction marks the version). ## Tests Two new tests in `session::storage::tests`: - `load_session_migrates_pre_f8_files`: writes a minimal pre-F8 session JSON (no schema_version field) to disk, loads it, asserts schema_version is bumped to SCHEMA_VERSION and the data is intact. - `load_session_corrupted_file_includes_path_in_error`: writes a truncated JSON, asserts the error mentions the path so the user can grep `dirge` logs and identify the broken file. 664 pass (was 662). All build profiles clean. Co-authored-by: Yogthos <yogthos@gmail.com>
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Track F-HIGH #8.
Sessiongainsschema_version: u32with serde default 0 for pre-F8 files.load_sessionrunsmigrate_sessionon version-lower files, warns on version-higher, and wraps corrupted-JSON errors with the file path so users can identify which session is broken. 2 new tests, 664 pass.