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Lite and the Darling Viewer: every clipboard write retries instead of crashing when the clipboard is busy (#4594) - #4600
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… on a truncated single-statement copy The Windows clipboard is a shared resource; another process holding it briefly (a clipboard manager, Office, RDP) makes an unguarded write throw and crash the app, the same failure #2833 already fixed for reads. ClipboardText gains a guarded TrySetText, mirroring TryRead's bounded retry, and every Clipboard.SetText/SetDataObject call in the shared plan viewer, blocking chain, deadlock graph, and DataGrid export helpers now routes through it. Copy Query Text on a truncated single-statement plan now hands back the full query the plan was captured from instead of the plan's own 4,000-character showplan-capped copy, matching PerformanceStudio's fix. The guard counts statements the way the Statements grid counts them (descending into stored procedure and UDF bodies), not by outer batch, so a plan captured around EXEC dbo.SomeProc is correctly treated as multi-statement and never hands back the outer EXEC for a truncated body statement. Fixes #4582
…ling Viewer through the guarded writer (#4594) Adds ClipboardText.TrySetDataObject (a SetDataObject sibling to #4593's TrySetText, same bounded retry) and routes every remaining Clipboard.SetText / Clipboard.SetDataObject call in Lite and the Darling Viewer through it, so a busy clipboard retries instead of crashing the app. Sites that already showed a status line on success now show a short failure message instead of silently dropping the copy; sites with no prior status handling keep quietly swallowing a failed copy, matching TrySetText's own behavior. Adds ClipboardWriteCensusTests: no source file under Lite/, Darling/ or PerformanceMonitor.Ui/, other than ClipboardText.cs itself, may call Clipboard.SetText( or Clipboard.SetDataObject( in code.
…oard # Conflicts: # PerformanceMonitor.PlanAnalysis/PlanDisplayText.cs # PerformanceMonitor.Ui/ClipboardText.cs
…dText.TrySetText Merging dev brought in a properties-panel copy path with its own bare-try guard around Clipboard.SetText, added after #4593/#4600 branched. It didn't route through the shared ClipboardText helper, so ClipboardWriteCensusTests failed post-merge. Delegate to ClipboardText.TrySetText instead of duplicating the guard.
erikdarlingdata
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September 28, 2026 16:35
This was referenced Sep 28, 2026
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Fixes #4594. Builds on #4593.
What changed
#4593 added
ClipboardText.TrySetText(inPerformanceMonitor.Ui), a bounded-retry guard aroundClipboard.SetTextthat returnsfalseinstead of throwing when another process momentarily holds theWindows clipboard, and routed the shared plan viewer, blocking chain, deadlock graph and grid-export
copies through it. This PR routes the remaining 18 unguarded clipboard writes in Lite and the Darling
Viewer through the same guard.
ClipboardText.TrySetDataObject(object data, bool copy = false), aSetDataObjectsibling toTrySetTextwith the identical bounded retry, for call sites that useSetDataObject(the existingconvention to avoid WPF's
Clipboard.Flush()) and for the chart bitmap copy, which has no textequivalent.
TrySetText/TrySetDataObject:Helpers/ContextMenuHelper.cs(4 sites, including the chart bitmap copy),Controls/ServerTab.CopyExport.cs,Controls/RecommendationsTab.xaml.cs(2),Windows/SettingsWindow.xaml.cs,Windows/AlertDetailWindow.xaml.cs,Windows/EntraDeviceCodeWindow.xaml.cs.MainWindow.xaml.cs(3),ViewerServerTab.CopyExport.cs,ViewerServerTab.ChartContextMenu.cs,SettingsWindow.xaml.cs(2),AlertDetailWindow.xaml.cs.the MCP command/URL copy buttons), a failed copy now shows "Couldn't copy: the clipboard is in use."
instead of silently dropping it. Where a site had no prior status handling (the grid/row/cell/chart
copies, the alert detail T-SQL copy, the device-code copy), a failed copy is still swallowed quietly,
matching
TrySetText's own default behavior for those paths.Darling/Darling.Tests/ClipboardWriteCensusTests.cs: walks every.csfile underLite/,Darling/andPerformanceMonitor.Ui/(viaCSharpSourceWalker, so comments/strings can't trip orhide it;
deprecated/excluded) and fails if any file other thanClipboardText.csitself still callsClipboard.SetText(orClipboard.SetDataObject(.RED on the pre-fix code
Checked out the census test alone against
2b5d2b3fe(the #4593 tip this branch is stacked on) in athrowaway worktree. It failed, listing the 11 files carrying the 18 unguarded sites:
On this branch's code, the same test passes.
Build and test
Built (macOS,
-p:EnableWindowsTargeting=true,-v q, all 0 warnings / 0 errors):Darling.Tests,Lite/PerformanceMonitorLite.csproj,Lite.Tests,PerformanceMonitor.Darling.Viewer,PerformanceMonitor.Ui.Ran
Darling.Tests.dllin-process (strippedMicrosoft.WindowsDesktop.Appfrom the runtimeconfig):ClipboardWriteCensusTests,Viewer4582Tests,CommentFilterAdoptionTests,DocCommentHygieneTests,and every
*Census*class in the tree (DailyDeadlockWindowCensusTests,EntraProviderPackageCensusTests,FileGrowthRiseUnitCensusTests,McpPayloadContractCensusTests,McpServiceParameterDiSeatCensusTests,MeasurementContractCensusTests,MigrationDataMovingRungCensusPins,PgSettingScrubCandidateCensusTests,PlanForceActionDetailCensus,PlanForceActionDetailCensusTests,RemoteCollectorServiceCancellationCensusTests,SameStatementPileupSourceCensusTests,StoreApplicationNameCensusTests,StoreSessionTimeZonePinCensusTests,WebExceptionTextCensusTests,McpToolsListBudgetTests): Total:360, Errors: 0, Failed: 0, Skipped: 1, Not Run: 0.
Lite.Testsbuilds but does not run on macOS (net10.0-windows,PresentationFramework); no test in thisPR's scope touches Lite.Tests directly (Lite's product code changes are the clipboard call sites only, no
new members/log text), so no Lite.Tests class needed a by-hand read.
CHANGELOG
SECTION: Fixed
ENTRY: - Copying from Lite or the Darling Viewer no longer crashes when another program holds the clipboard ([#4600]) - Every remaining unguarded clipboard write (recommendation copy/AI-prompt buttons, MCP command/URL copy, grid/row/cell copy, chart image copy, alert detail T-SQL copy, sign-in device-code copy) now retries briefly instead of throwing when another process is holding the clipboard.
REF: [#4600]: #4600