v4.0.0

Version 4.0.0 changes the provider and backend model to function as plugins resolved through the NuGet package manager.

Added

• Third-party providers and backends. A PROVIDER / BACKEND block can name any plugin package with a source attribute.
• nschema init now restores plugins. init now pre-fetches the provider and backend plugins pinned in your config. Operations restore implicitly on first use; init just does it up front so the first real command is fast.
• --no-init flag. Skips the implicit plugin restore and requires the plugins to be cached already.
• lock command group. nschema lock status / lock acquire / lock release inspect, manually hold, and release the state lock. lock acquire holds a lock that outlives the command (for out-of-band checks before a migration), with an optional --ttl (e.g. 30m) and --reason, lock status surfaces any information about the currently held lock. lock release requires the lock id by default (refusing if it no longer matches the held lock), with --force to release whatever lock is held without naming it.
• --no-lock flag on apply, refresh, and destroy. Runs without taking the state lock.
• nschema state show <file> renders a state file on disk directly, without a configured backend.
• nschema db show renders the live database schema, read directly from the database via the provider — the online counterpart to state show.
• plugin command group. nschema plugin list shows the provider and backend plugins your project pins and whether each is restored; plugin show prints one plugin's detail (package, pinned version, cache status).plugin cache list/plugin cache remove [version]/plugin cache clearinspect and prune the shared plugin cache at~/.nschema/plugins`.
• --format option (text | json | markdown), selecting the output format for any command. --json is now shorthand for --format json.
• Markdown output. --format markdown renders the plan, SQL, and schema as Markdown for a PR comment or a CI job summary.

Changed

• Providers and backends are now plugins. They ship as separate NuGet packages instead of being bundled with the tool; nschema restores the one pinned in your config on first use (it shells out to the .NET SDK to do so). The local-file state backend remains built in.
• Scaffolding moved from init to nschema scaffold. Creating a starter project is now nschema scaffold (init became the restore command above). Its PROVIDER / BACKEND config blocks and the sample schema are rendered by the plugins themselves.
• PROVIDER / BACKEND blocks now require a pinned version (the plugin package version); the built-in file backend is the exception. A first-party label (postgres, sqlite, sqlserver, s3) still resolves to its package automatically.
• A PROVIDER block is now required to select a provider. NSCHEMA_POSTGRES_CONNECTION_STRING and the other connection-string variables no longer name the provider on their own — they still override the connection string set in the block.
• doctor reports plugin problems as diagnostics. A provider or backend that fails to restore or configure is now reported by doctor as a health-check finding (every such problem at once) instead of aborting on the first.
• Lock commands grouped under lock. lock-status → nschema lock status; force-unlock → nschema lock release, whose prompt is now skipped with --auto-approve/-y (consistent with apply/destroy) instead of --force. The lock-id safety check is unchanged.
• show split by what it shows. The recorded state is now nschema state show (offline; the state noun group will grow pull/push/move), and a saved plan is nschema plan show <file>. The top-level show command is gone.
• completion install / completion uninstall subcommands replace the --install-autocomplete / --uninstall-autocomplete flags. nschema completion <shell> still prints the script.
• Built on NSchema.Core 4.0.0 and the 4.0 provider/backend packages.

Fixed

• Running nschema --help in a busy directory like root would cause a performance slowdown due to the --environment arg autocomplete recursively scanning all the files in the directory. This has been fixed by removing autocomplete.
• Torn reads of the local state file. The built-in file state store now writes to a temporary sibling file and atomically renames it into place, so a command reading the recorded state while another run writes it.

Removed

• The NSCHEMA config block. destructive_action moved to the --destructive-actions flag / the NSCHEMA_DESTRUCTIVE_ACTION_POLICY environment variable; dialect and transaction_mode (never wired in) are gone. An NSCHEMA block is now rejected as an unknown configuration block.
• The top-level show, lock-status, and force-unlock commands, replaced by state show / plan show and the lock group above. The show --online live-schema view is now nschema db show (a db noun group) rather than a mode flag.