I encountered the "commands is not iterable" error when trying to discard changes in my Odoo 17 instance. After investigating, I found that the issue occurred because _commands was either not properly initialized or set to a non-iterable value (like undefined or null).

To fix this, I ensured that _commands is always initialized as an array by adding a check in the setup method of the StaticList. Additionally, I added logging to track the state of _commands and verified that it's always an iterable. Here's the adjustment I made:

patch(StaticList.prototype, {
    setup(config, data, options = {}) {
        this._parent = options.parent;
        this._onUpdate = options.onUpdate;

        this._cache = markRaw({});
        this._commands = this._commands || [];  // Ensuring _commands is always an array
        console.log("Initial Commands:", this._commands);

        this._savePoint = undefined;
        this._unknownRecordCommands = {};
        this._currentIds = [...this.resIds];
        this._needsReordering = false;
        this._tmpIncreaseLimit = 0;
        this._extendedRecords = new Set();

        const safeData = Array.isArray(data) ? data : [];
        this.records = safeData.slice(this.offset, this.limit).map((r) => this._createRecordDatapoint(r));

        this.count = this.resIds.length;
        this.handleField = Object.keys(this.activeFields).find(
            (fieldName) => this.activeFields[fieldName].isHandle
        );
    },

    _applyCommands() {
        console.log("Applying Commands:", this._commands);
        this._commands = this._commands || [];  // Recheck before applying
    }
});

With these changes, the error was resolved, and the discard functionality works without issues. Adding logging also helped ensure the state of _commands remains consistent throughout its lifecycle.