Read lck and ulck exposure policy — Boundary detective

PART I

Warm-up

Reconnect with a useful idea before starting read lck and ulck exposure policy. In one or two sentences, describe the input, output or host boundary from the previous exercise that this lesson builds on. If you are arriving directly, skim the worked example first; there is no locked prerequisite.

A rough note is enough. You can revise it after the example.

PART II

Instruction & guided example

Find an indirect internal exposure

An exposure policy must say which surface is reachable. Read lck and ulck as the source’s exposure-policy concepts, separately from resource grants. The source does not supply a complete deployable manifest grammar here. Write policy tables and review their meaning instead of inventing a parser-verified declaration.

Public preview(target) calls internal rawRead(target). rawRead has no separate permission check. preview accepts arbitrary resource names from the mod instead of restricting them to approved preview assets.

Enumerate the public operations before reviewing permissions. Removing a UI button does not remove an API surface. A helper reachable indirectly from an exposed entry point still needs its own boundary analysis; names and namespaces do not prove isolation. Worked case: Although rawRead is not directly public, preview can act as a reachable path to its effects. The review must constrain preview targets and require resource authorization before rawRead can access them.

Compare the tempting alternative: Marking rawRead internal is insufficient when an exposed caller forwards arbitrary untrusted targets to it.

Worked reasoning and supplied artifact

// Paper trace / supplied exercise-host contract; no execution claimed.
// Public preview(target) calls internal rawRead(target). rawRead has no separate permission check. preview accepts arbitrary resource names from the mod instead of restricting them to approved preview assets.
// Although rawRead is not directly public, preview can act as a reachable path to its effects. The review must constrain preview targets and require resource authorization before rawRead can access them.

Illustrative example from the proposed WillowScript design. The language and WUIX/WMATH/WDB/WAUDIO/WTMP services are not implemented in the supplied source. This site has no interpreter, VM or native host and does not execute or certify the snippet.

Try the guided change

Reconstruct the supplied worked case first: list its inputs, intermediate decisions and final artifact. Compare each row with the explanation and identify exactly where the rejected alternative fails. Then use the changed inputs in Part IV for independent work.

• Write the supplied inputs and initial state before following the example.
• Reconstruct each intermediate calculation or host decision, then compare with the worked artifact.
• Explain why the contrasting alternative fails before attempting the changed inputs in Part IV.

PART III

Take a breather

Step back after the guided example. Look away from the screen, stretch, or reread your prediction. This is an optional learning pause, not a timer or an assessment gate.

When you return, try to name the lesson’s key idea without copying its wording. If that feels difficult, return to Part II and trace one line rather than restarting the entire lesson.

PART IV

Independent practice

Project context: Safe extension design. Build a small, understandable change around read lck and ulck exposure policy.

Draw the reachable call graph for public-preview and protected-ledger targets. Put the required validation before the internal effect.

What to produce

A two-target call graph with authorization and target-scope postconditions.

• State the intended behavior in a sentence before editing.
• Use only source-backed syntax and the host services whose contract you have been given.
• Record a normal case and a boundary or unavailable-resource case.
• Label hand predictions separately from anything actually measured in a supplied toolchain.

Syntax colors are a reading aid, not a compiler. The line you are editing stays uncolored until you move to a different line; capitalization is never changed. Drafts stay on this browser and code is not executed.

import wuix.widget;
const button = widget.Button({
    text: "Continue",
    events: {
        click: fnc() -> void {
            navigator.open("dashboard");
        }
    }
});

PART V

Self-check

Use this check to notice what to revisit. It does not award a private course grade, block another page or claim to verify compiled code. Every answer has a learning explanation.

You may keep exploring even if you are unsure. Use the hint, compare the trace, and revise your explanation.

PART VI

Recap & small task

Bring the idea back to the mod feature you are building. A useful recap connects the mechanism to a decision you can make in your own code.

• Find an indirect internal exposure
• Draw the reachable call graph for public-preview and protected-ledger targets. Put the required validation before the internal effect.
• Separate source-backed behavior, host requirements and untested predictions.

One small recap task

Mark the earliest point where the target can be constrained.

This marks your personal practice record only. It is not a certification or an official workspace assessment.