cli: add headless command-line layer (bal_* commands for the daemon, cmdline entry point, manifest 'cmdline' support, offline controller tests)

bal/__init__.py

@@ -24,11 +24,18 @@ distinct sub-packages:
                 lists.py     Tree/list views (heirs, preview, will-executors)
                 window.py    BalWindow controller (per-wallet GUI state)
                 plugin.py    Plugin class wiring Electrum @hooks to the GUI
+        cli/             Headless command-line layer (no Qt)
+            commands.py     The @plugin_command transport layer (registers
+                            the ``bal_*`` commands)
+            controller.py   Headless replica of the Qt flows (later phases)
+            plugin.py       Plugin(BalPlugin) entry point for the daemon
         qt.py            Thin loader shim re-exporting `Plugin` for Electrum
+        cmdline.py       Thin loader shim re-exporting `Plugin` for the daemon
 
 Electrum discovers the plugin through ``manifest.json`` and loads the GUI
 entry point from ``qt.py`` (the shim), which imports the real ``Plugin``
-from ``gui.qt.plugin``.
+from ``gui.qt.plugin``; the command-line/daemon entry point is ``cmdline.py``
+(the shim), which imports ``Plugin`` from ``cli.plugin``.
 
 The plugin supports Electrum 4.7.2 and 4.8.0 with PyQt6.  Electrum 4.8.0 removed
 ``json_db.register_dict`` and replaced it with the path-based
@@ -40,3 +47,85 @@ available and adapts, so both releases keep working.
 # (the single source of truth) and is read at runtime via ``get_version()`` in
 # ``bal/core/plugin_base.py`` (exposed as the ``BalPlugin.version`` property).
 # Keeping a hardcoded ``__version__`` here would just be a stale duplicate.
+
+# --------------------------------------------------------------------------- #
+# CLI command registration
+# --------------------------------------------------------------------------- #
+# Electrum's CLI pre-parse (run_electrum calls ``Plugins(config, cmd_only=True)``)
+# only imports the plugin package ``__init__`` to discover its commands.
+# Importing ``bal.cli.commands`` here registers every ``bal_*`` command with
+# ``electrum.commands`` (``known_commands`` + the ``Commands`` class), so the
+# commands become available on the command line and over JSON-RPC without any Qt.
+#
+# The import must be zip-safe: when the plugin is loaded as an external zip,
+# Electrum registers the package under the synthetic name
+# ``electrum_external_plugins.bal``, but the module's ``__package__`` is only
+# ``bal`` (the zip-internal directory name), which is not present in
+# ``sys.modules`` and cannot be used for sub-module imports.  We therefore
+# resolve the real package name and import through ``importlib`` (the same
+# trick as ``qt.py``).
+import importlib
+import sys as _sys
+
+
+def _resolve_package_name() -> str:
+    """Return the name this package is registered under in ``sys.modules``.
+
+    Internal plugins are imported as ``electrum.plugins.bal`` (a normal import,
+    so ``__package__`` is already correct).  External zip plugins are imported
+    under the synthetic name ``electrum_external_plugins.bal`` with
+    ``__package__`` set to just the zip-internal directory name (``bal``); only
+    the synthetic name is present in ``sys.modules``.
+    """
+    pkg = __package__ or "bal"
+    if pkg in _sys.modules:
+        return pkg
+    synthetic = "electrum_external_plugins." + __name__
+    if synthetic in _sys.modules:
+        return synthetic
+    return pkg
+
+
+def _ensure_parent_packages(pkg_name: str) -> None:
+    """Backfill missing ancestor packages in ``sys.modules``.
+
+    When loaded from a zip as an external plugin, Electrum only executes the
+    package ``__init__``; the synthetic root package (``electrum_external_plugins``)
+    may be missing, which would break sub-module imports.  We stub it out as a
+    namespace package so ``importlib`` can still resolve its children (same
+    helper as ``qt.py``).
+    """
+    parts = pkg_name.split(".")
+    for i in range(1, len(parts)):
+        ancestor = ".".join(parts[:i])
+        if ancestor in _sys.modules:
+            continue
+        try:
+            importlib.import_module(ancestor)
+        except Exception:
+            import types
+
+            module = types.ModuleType(ancestor)
+            module.__path__ = []  # mark as a (namespace) package
+            _sys.modules[ancestor] = module
+
+
+def _register_cli_commands() -> None:
+    """Import ``bal.cli.commands`` so Electrum registers the ``bal_*`` commands.
+
+    Guarded so a dual install (internal package AND external zip) cannot
+    register the same command names twice, which would make
+    ``electrum.commands.plugin_command`` raise
+    "Command name bal_... already exists".
+    """
+    from electrum import commands as _electrum_commands
+
+    if getattr(_electrum_commands, "_bal_cli_commands_registered", False):
+        return
+    pkg = _resolve_package_name()
+    _ensure_parent_packages(pkg)
+    importlib.import_module(pkg + ".cli.commands")
+    _electrum_commands._bal_cli_commands_registered = True
+
+
+_register_cli_commands()