Test missing and damaged saves safely

Worked example

A validated save contains known scalar fields and a version. An array instead of a dictionary is syntactically valid JSON but should still be rejected by the schema. Scaffold C-SAVE — Small, validated local best-score save Setup: Attach to Node SaveLab. Only saves version and integer best score to user://course_best.json. No nodes, paths from a save file, private data or scripts are loaded. Functions return safe defaults for missing/invalid data. Test in desktop editor, using a course-only filename so existing game saves are untouched. Do not edit unrelated user:// files. ```gdscript extends Node const PATH: String = "user://course_best.json" func write_best(best: int) -> bool: var file := FileAccess.open(PATH, FileAccess.WRITE) if file == null: return false file.store_string(JSON.stringify({"version": 1, "best": clampi(best, 0, 999999)})) file.close() return true func read_best() -> int: if not FileAccess.file_exists(PATH): return 0 var file := FileAccess.open(PATH, FileAccess.READ) if file == null: return 0 var text: String = file.get_as_text() file.close() var parser := JSON.new() if parser.parse(text) != OK: return 0 var parsed: Variant = parser.data if not parsed is Dictionary: return 0 var data: Dictionary = parsed if data.get("version", 0) != 1: return 0 var best: Variant = data.get("best", 0) if not (best is int or best is float): return 0 return clampi(int(best), 0, 999999) func _ready() -> void: print("Saved best: ", read_best()) ``` 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) ```

Small, validated local best-score save

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

Scene and node setup

Attach to Node SaveLab. Only saves version and integer best score to user://course_best.json. No nodes, paths from a save file, private data or scripts are loaded. Functions return safe defaults for missing/invalid data. Test in desktop editor, using a course-only filename so existing game saves are untouched. Do not edit unrelated user:// files.

extends Node
const PATH: String = "user://course_best.json"
func write_best(best: int) -> bool:
    var file := FileAccess.open(PATH, FileAccess.WRITE)
    if file == null:
        return false
    file.store_string(JSON.stringify({"version": 1, "best": clampi(best, 0, 999999)}))
    file.close()
    return true
func read_best() -> int:
    if not FileAccess.file_exists(PATH):
        return 0
    var file := FileAccess.open(PATH, FileAccess.READ)
    if file == null:
        return 0
    var text: String = file.get_as_text()
    file.close()
    var parser := JSON.new()
    if parser.parse(text) != OK:
        return 0
    var parsed: Variant = parser.data
    if not parsed is Dictionary:
        return 0
    var data: Dictionary = parsed
    if data.get("version", 0) != 1:
        return 0
    var best: Variant = data.get("best", 0)
    if not (best is int or best is float):
        return 0
    return clampi(int(best), 0, 999999)
func _ready() -> void:
    print("Saved best: ", read_best())

Checks to run in the editor

• Missing or malformed JSON returns zero without crashing.
• Write 42, stop, restart: read 42.
• String best and unknown version return zero.

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.

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.

Test missing and damaged saves safely — evidence task

1. 1. Run five corrupted/missing-data cases using the course-only path.
2. 2. Restore the valid file and verify the normal case again.

Deliverable. Save robustness log and repaired normal-save checkpoint.

Acceptance checks

• VGC-L115-T1. No case crashes or loads an arbitrary resource.
• VGC-L115-T2. The game communicates fallback versus successful restore.

Understanding question. Why test the normal save again after fault cases?

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. Use the course-specific save filenames in C-SAVE and C-STATE-SAVE. Never edit unrelated game saves or load scripts from save data. Start with the first assigned task and re-run its acceptance test before adding the remaining feature.

Optional extra. Add a new fixed scalar field with a safe default and explicit validation. Document one changed parameter, your prediction, and the observed effect; optional, not required for completion.

Turn in typed notes and a JPEG, PNG, or WebP screenshot. One https address is stored as text and is not opened, extracted, or run. An MP3, WAV, M4A, MP4, or WebM file up to 4 MB can show a demo. The demo does not replace editable source. Zip and code files are refused. If there is no private link, keep the project on the family computer and review the code in person.

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

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• Saving games: FileAccess and JSON

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