Add a versioned schema change deliberately

Worked example

A reset matrix separates round score, saved progress and comfort preferences. Restarting a round may clear score while retaining a mute preference, if documented. Scaffold C-STATE-SAVE — Validated inventory and checkpoint data Setup: Attach to a Node named SaveData. This is a separate file from C-SAVE and only reads fixed known scalar fields. get_checkpoint_data returns plain data, not live node references. When applying a loaded checkpoint, the assignment maps checkpoint ID to a teacher-approved safe Marker2D, never to a filename supplied by the save. ```gdscript extends Node const PATH: String = "user://seed_station_v1.json" func defaults() -> Dictionary: return {"version": 1, "seed": 0, "water": 0, "checkpoint": "start"} func _bounded_count(value: Variant) -> int: if value is int or value is float: return clampi(int(value), 0, 99) return 0 func validate(raw: Variant) -> Dictionary: var clean := defaults() if not raw is Dictionary: return clean var data: Dictionary = raw if data.get("version", 0) != 1: return clean clean["seed"] = _bounded_count(data.get("seed", 0)) clean["water"] = _bounded_count(data.get("water", 0)) var checkpoint: Variant = data.get("checkpoint", "start") if checkpoint is String and checkpoint in ["start", "greenhouse"]: clean["checkpoint"] = checkpoint return clean func save_data(raw: Dictionary) -> bool: var file := FileAccess.open(PATH, FileAccess.WRITE) if file == null: return false file.store_string(JSON.stringify(validate(raw))) file.close() return true func load_data() -> Dictionary: if not FileAccess.file_exists(PATH): return defaults() var file := FileAccess.open(PATH, FileAccess.READ) if file == null: return defaults() var text: String = file.get_as_text() file.close() var parser := JSON.new() if parser.parse(text) != OK: return defaults() return validate(parser.data) ``` Scaffold C-WORLD-DATA — Consistent pickup/bed persistence with derived inventory Setup: Attach to a separate Node named WorldData. This is the default integrated Seed Station model after the scalar-save lab. Fixed pickup IDs are s1,s2,s3,w1,w2; fixed bed IDs are b1,b2. Manager records picked IDs only after a successful pickup and planted IDs only after validating both resource costs. Inventory is derived from these IDs, so reloading cannot keep quantities while respawning already-picked rewards. On load, hide/free picked objects, mark planted beds, set the known start/greenhouse marker, then refresh HUD. Version 1 scalar labs are intentionally not migrated: report a new-game fallback. ```gdscript extends Node const PATH: String = "user://seed_station_world_v2.json" func defaults() -> Dictionary: return {"version": 2, "picked": [], "planted": [], "seed": 0, "water": 0, "checkpoint": "start"} func _ids(raw: Variant, allowed: Array) -> Array[String]: var clean: Array[String] = [] if raw is Array: for value in raw: if value is String and value in allowed and value not in clean: clean.append(value) return clean func validate(raw: Variant) -> Dictionary: var result := defaults() if not raw is Dictionary: return result var data: Dictionary = raw if data.get("version", 0) != 2: return result var picked := _ids(data.get("picked", []), ["s1", "s2", "s3", "w1", "w2"]) var planted := _ids(data.get("planted", []), ["b1", "b2"]) var seed_total: int = 0 var water_total: int = 0 for id in picked: if id.begins_with("s"): seed_total += 1 else: water_total += 1 while planted.size() > mini(seed_total, water_total): planted.pop_back() result["picked"] = picked result["planted"] = planted result["seed"] = seed_total - planted.size() result["water"] = water_total - planted.size() result["checkpoint"] = "greenhouse" if "b1" in planted else "start" return result func save_data(raw: Dictionary) -> bool: var file := FileAccess.open(PATH, FileAccess.WRITE) if file == null: return false file.store_string(JSON.stringify(validate(raw))) file.close() return true func load_data() -> Dictionary: if not FileAccess.file_exists(PATH): return defaults() var file := FileAccess.open(PATH, FileAccess.READ) if file == null: return defaults() var text: String = file.get_as_text() file.close() var parser := JSON.new() if parser.parse(text) != OK: return defaults() return validate(parser.data) ```

Validated inventory and checkpoint data

GDScript (Godot 4, not Scratch, Python, JavaScript or C#). Scaffold C-STATE-SAVE. Copy starts from this text. The desk does not run it.

Scene and node setup

Attach to a Node named SaveData. This is a separate file from C-SAVE and only reads fixed known scalar fields. get_checkpoint_data returns plain data, not live node references. When applying a loaded checkpoint, the assignment maps checkpoint ID to a teacher-approved safe Marker2D, never to a filename supplied by the save.

extends Node
const PATH: String = "user://seed_station_v1.json"
func defaults() -> Dictionary:
    return {"version": 1, "seed": 0, "water": 0, "checkpoint": "start"}
func _bounded_count(value: Variant) -> int:
    if value is int or value is float:
        return clampi(int(value), 0, 99)
    return 0
func validate(raw: Variant) -> Dictionary:
    var clean := defaults()
    if not raw is Dictionary:
        return clean
    var data: Dictionary = raw
    if data.get("version", 0) != 1:
        return clean
    clean["seed"] = _bounded_count(data.get("seed", 0))
    clean["water"] = _bounded_count(data.get("water", 0))
    var checkpoint: Variant = data.get("checkpoint", "start")
    if checkpoint is String and checkpoint in ["start", "greenhouse"]:
        clean["checkpoint"] = checkpoint
    return clean
func save_data(raw: Dictionary) -> bool:
    var file := FileAccess.open(PATH, FileAccess.WRITE)
    if file == null:
        return false
    file.store_string(JSON.stringify(validate(raw)))
    file.close()
    return true
func load_data() -> Dictionary:
    if not FileAccess.file_exists(PATH):
        return defaults()
    var file := FileAccess.open(PATH, FileAccess.READ)
    if file == null:
        return defaults()
    var text: String = file.get_as_text()
    file.close()
    var parser := JSON.new()
    if parser.parse(text) != OK:
        return defaults()
    return validate(parser.data)

Checks to run in the editor

• Missing file returns defaults.
• Negative count becomes zero; count 1000 becomes 99.
• Unknown checkpoint becomes start.
• Malformed JSON, arrays and unsupported versions return safe defaults.

Native Godot 4.7.2.stable.official.ed1daf0bf headless compile and representative node-tree/runtime tests passed; see native-qa-results.json. Visual UI, audible output, exports and website submission still need separate checks.

Consistent pickup/bed persistence with derived inventory

GDScript (Godot 4, not Scratch, Python, JavaScript or C#). Scaffold C-WORLD-DATA. Copy starts from this text. The desk does not run it.

Scene and node setup

Attach to a separate Node named WorldData. This is the default integrated Seed Station model after the scalar-save lab. Fixed pickup IDs are s1,s2,s3,w1,w2; fixed bed IDs are b1,b2. Manager records picked IDs only after a successful pickup and planted IDs only after validating both resource costs. Inventory is derived from these IDs, so reloading cannot keep quantities while respawning already-picked rewards. On load, hide/free picked objects, mark planted beds, set the known start/greenhouse marker, then refresh HUD. Version 1 scalar labs are intentionally not migrated: report a new-game fallback.

extends Node
const PATH: String = "user://seed_station_world_v2.json"
func defaults() -> Dictionary:
    return {"version": 2, "picked": [], "planted": [], "seed": 0, "water": 0, "checkpoint": "start"}
func _ids(raw: Variant, allowed: Array) -> Array[String]:
    var clean: Array[String] = []
    if raw is Array:
        for value in raw:
            if value is String and value in allowed and value not in clean:
                clean.append(value)
    return clean
func validate(raw: Variant) -> Dictionary:
    var result := defaults()
    if not raw is Dictionary:
        return result
    var data: Dictionary = raw
    if data.get("version", 0) != 2:
        return result
    var picked := _ids(data.get("picked", []), ["s1", "s2", "s3", "w1", "w2"])
    var planted := _ids(data.get("planted", []), ["b1", "b2"])
    var seed_total: int = 0
    var water_total: int = 0
    for id in picked:
        if id.begins_with("s"):
            seed_total += 1
        else:
            water_total += 1
    while planted.size() > mini(seed_total, water_total):
        planted.pop_back()
    result["picked"] = picked
    result["planted"] = planted
    result["seed"] = seed_total - planted.size()
    result["water"] = water_total - planted.size()
    result["checkpoint"] = "greenhouse" if "b1" in planted else "start"
    return result
func save_data(raw: Dictionary) -> bool:
    var file := FileAccess.open(PATH, FileAccess.WRITE)
    if file == null:
        return false
    file.store_string(JSON.stringify(validate(raw)))
    file.close()
    return true
func load_data() -> Dictionary:
    if not FileAccess.file_exists(PATH):
        return defaults()
    var file := FileAccess.open(PATH, FileAccess.READ)
    if file == null:
        return defaults()
    var text: String = file.get_as_text()
    file.close()
    var parser := JSON.new()
    if parser.parse(text) != OK:
        return defaults()
    return validate(parser.data)

Checks to run in the editor

• Picked s1,s2,w1 and planted b1 yields seed1,water0,greenhouse.
• Duplicate s1 entries do not add extra inventory.
• No collected IDs plus two planted IDs cleans to no planted beds.
• Reload removes collected pickups and restores planted-bed state through the manager.

Native Godot 4.7.2.stable.official.ed1daf0bf headless compile and representative node-tree/runtime tests passed; see native-qa-results.json. Visual UI, audible output, exports and website submission still need separate checks.

Add a versioned schema change deliberately — evidence task

1. 1. Add one validated field and document old-version behavior.
2. 2. Test old version, current version and an unsupported future version.

Deliverable. Schema change note, validator source and three-version tests.

Acceptance checks

• VGC-L117-T1. The new field has a safe default.
• VGC-L117-T2. Unsupported versions follow the documented fallback instead of crashing.

Understanding question. Why not assume a larger version number means compatible data?

Include a downloadable project ZIP with project.godot, .tscn, .gd and original asset files when code changes. A private, teacher-accessible download link to that ZIP is equivalent. Screenshots or a playthrough do not replace editable source.

If this is still shaky. If full world persistence is too large, use the documented checkpoint-only reset policy. Do not claim unsaved flags persist. Start with the first assigned task and re-run its acceptance test before adding the remaining feature.

Optional extra. Add one small validated setting using a separate save field or configuration file. Document one changed parameter, your prediction, and the observed effect; optional, not required for completion.

• Godot step by step: nodes, scenes, GDScript, input, signals

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• Saving games: FileAccess and JSON

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