Fix session file loading crash, deploy the native DLL, and add a README

[Skorinn]

Four changes found by running the application rather than only its tests.

Opening a session file crashed the application

STATUS_STACK_OVERFLOW, confirmed in the Windows event log, faulting in ntdll.dll. The application died about two seconds after a file was opened.

Loading a session sets the simulate toggle to match the file it came from. The handler for that toggle worked out its new state by inverting what was recorded rather than by reading the toggle, then wrote the result back to the toggle from inside its own event:

Checked = true    (the file says simulated, the toggle is clear)
  -> Simulated = !true = false -> Checked = false -> fires again
  -> Simulated = !false = true -> Checked = true  -> fires again -> without end

This is reached by opening any session recorded in a different mode to the one currently selected, which includes the ordinary case of opening a simulated session in a freshly started application. The file itself has nothing to do with it: a properly closed file and one left unfinished both brought the application down in the same way.

The handler now takes its state from the toggle and no longer writes to it, so setting it from code settles. A test covers the invariant, reaching the toggle by reflection as it is not exposed.

This blocked the recovery of unfinished session files entirely. That work went through five rounds of review on the previous pull request and could not be reached through the interface at all.

The native DLL was never deployed next to the application

Starting a session threw DllNotFoundException for TruRNGpro.dll. The build placed it in the solution bin directory and in the test output, but nothing put it beside the application in its own output directory, which is where the application runs from and so where it looks for it. The test project had been copying it into its own output all along, which is why the tests exercised the device interface while the application could not load it.

README

Describes what the application records and analyses, how to build and run it, the session file format and the recovery behaviour, the layout of the three projects, and how to run the tests. It also notes that the licensing of the third-party header in TruRNGpro has not been established, which is worth settling before the code is distributed.

CommonControls.dll

Updated to the build supplied for this work. There is no source for it here, so it is carried as a binary the same way DeviceInterfaces.dll is.

Verification

Driven through the interface with the controls operated directly, rather than against the classes behind them:

Execute tab	38 of 38
Analyze tab and recovery	13 of 13
Unit tests	207 of 207

Covering recording (average 0.499973, standard deviation 3.94e-3), pause and resume halting and continuing at the exact point counts, loading and appending 81 to 113 points, the baseline against result comparison, and recovery end to end: the application killed while recording, reopened, 50 points recovered, the recovery reported to the user, the session continued to 82 points and the file left valid.

🤖 Generated with Claude Code

https://claude.ai/code/session_0153VVkWg7DQmdaNLcvtY37w

[Copilot]

🟢 Approval recommended

The changes directly address the reported crash and deployment issue with low-risk, well-scoped edits and include a regression test for the crash scenario.

Pull request overview

Fixes a WinForms crash when loading session files by preventing recursive toggling of the Simulate checkbox, ensures the native TruRNGpro.dll is deployed alongside the application output so the app can actually P/Invoke it at runtime, and documents build/run/test and session-file details in a new README.

Changes:

• Prevent infinite recursion/stack overflow by updating the simulate-toggle handler to read from the control state (and not write back into it).
• Add a component test that exercises setting the simulate toggle from code (regression coverage for the crash path).
• Copy TruRNGpro.dll into the application output directory during the app project’s post-build step, and add a repository README with build/run/test guidance and file format notes.

File summaries

File	Description
README.md	Adds documentation for purpose, build/run steps, tests, and session XML format/recovery behavior.
RandomNumberGenerator.Test/GeneratorForm.Test.cs	Adds a regression test covering programmatic simulate-toggle setting without re-entrant toggling.
RandomNumberGenerator.csproj	Updates post-build to deploy TruRNGpro.dll into the app output folder.
GeneratorForm.cs	Fixes simulate-toggle event handling to avoid recursive CheckedChanged behavior.

Review details

• Files reviewed: 4/5 changed files
• Comments generated: 0
• Review effort level: Lite

---

💡 Add a code-review agent skill or configure MCP servers for context-aware, tailored reviews. Learn more in the docs.