Kernel: a control result is rendered, not also dumped as text by sierragolflima · Pull Request #861 · Systemorph/MeshWeaver

sierragolflima · 2026-08-06T12:33:02Z

The defect

A cell whose last expression is a control printed the control's record ToString() into its own output pane, beside the thing it describes:

StackControl { Id = , Style = , Readonly = , Skins = System.Collections.Immutable.ImmutableList`1[MeshWeaver.Layout.Skin], Class = , IsClickable = False, DataContext = , … }
✓ Done
INFO
StackControl { Id = , Style = , … }

Reported on https://memex.meshweaver.cloud/RiskTransfer/01-GrossToNet, under the rendered "The 2025 Loss Book" grid.

The cause

KernelExecutor handled a non-null result twice:

UpdateView(viewId, returnValue);                                       // renders it — correct
scriptOutputLogger.LogInformation("{Value}", returnValue.ToString());  // …and dumps it as text

The fix

Guard the log on the result not being a control. The log line stays for everything else — for 1 + 1 it is the only output a learner sees — so this checks the type rather than removing the line. IUiControl is the interface UiControl implements, so it covers every control.

The test asserts both directions

Silencing the logger outright would suppress the dump and quietly break every scalar cell. A one-sided test would pass on that wrong fix, so KernelControlResultNotLoggedTest pins the distinction, measured on one run:

	Control cell log	Scalar cell log
Without the fix	`StackControl { Id = , Style = , … }`	`scalar-result-42-marker`
With the fix	(empty)	`scalar-result-42-marker`

One thing the test encodes deliberately

Each cell gets its own activity node, and the assertion waits for a terminal status before reading. The activity log is replaced per submission, not accumulated — two cells on one activity leaves only the second cell's log. An earlier draft of this test passed twice against a log that never contained the value under test, so that reasoning is written into the test summary rather than left to be rediscovered.

Verification

dotnet build src/MeshWeaver.Kernel.Hub -c Release -warnaserror — clean, before and after merging current main
The test fails against unfixed code and passes with the fix, re-confirmed on the merged tree
Branch merged with current main (12 commits) before opening

Not addressed here

Whether these cells should be executable on a read-only course page at all is a separate design question and is deliberately left open.

🤖 Generated with Claude Code

A cell whose last expression is a control printed the control's record ToString() into its own output pane, beside the thing it describes: StackControl { Id = , Style = , Readonly = , Skins = System.Collections. Immutable.ImmutableList`1[MeshWeaver.Layout.Skin], Class = , IsClickable = False, DataContext = , ... } Visible under the loss-book grid on RiskTransfer/01-GrossToNet. KernelExecutor handled a non-null result twice: UpdateView renders it, and then the same object was logged via ToString(). The log line is correct for every other result — for `1 + 1` it is the only output the learner sees — so this guards on the type rather than removing the line. The test asserts BOTH directions on one run, because silencing the logger outright would suppress the dump and quietly break every scalar cell: without the fix control log: StackControl { ... } scalar log: scalar-result-42-marker with the fix control log: (empty) scalar log: scalar-result-42-marker Each cell gets its own activity node and the assertion waits for a TERMINAL status before reading. That is not incidental: the activity log is REPLACED per submission, not accumulated, so two cells on one activity leaves only the second cell's log — an earlier draft of this test passed twice against a log that never contained the value under test. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

…tostring-log

Copilot

Pull request overview

Fixes kernel cell output so that when a script’s last expression returns a layout control, the control is rendered via UpdateView but not also logged as text (avoiding StackControl { ... } record dumps in the output pane). Adds an integration test that asserts the distinction between control results (no dump) and scalar results (still logged as the only learner-visible output).

Changes:

Guard KernelExecutor result-logging so IUiControl return values are not logged as ToString().
Add KernelControlResultNotLoggedTest to assert: control result produces no StackControl { ... } dump, while scalar result still produces the expected logged marker.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
test/MeshWeaver.Hosting.Monolith.Test/KernelControlResultNotLoggedTest.cs	New integration test validating control results aren’t logged while scalar results still are.
src/MeshWeaver.Kernel.Hub/KernelExecutor.cs	Prevents duplicate output by skipping the result log line when the return value is an `IUiControl`.

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github-actions · 2026-08-06T12:40:12Z