[JohnCampionJr]

Some of the parser's Debug.WriteLine lines quote text taken from the output stream. A host that bridges Trace.Listeners into its logging then copies terminal data into its log. An OSC payload is program output: it can carry clipboard data (OSC 52), titles, hyperlinks, notification bodies or any text a program printed, including text from untrusted content such as cat of a file. This is the library-side counterpart of tomlm/Iciclecreek.Avalonia.Terminal#201, which stopped the control logging typed text.

Changes

I audited all 17 Debug writes in src/XTerm.NET (there are no Trace.* or Console.* calls) and changed 3, all in InputHandler.cs:

Site	Was	Now
unknown OSC	raw parts[0]: the text before the first ;, or the whole payload when there is none	the number if it parses as a plain integer, otherwise non-numeric command, N chars
unknown CSI	the full identifier (the parser collects any number of intermediates)	quoted only when 3 characters or fewer, otherwise final 'X' after N intermediates
unhandled OSC	the OscCommand enum name	(int)command, the numeric id (it was already safe; this keeps the OSC lines consistent)

Kept: the mode lines in InputHandler.cs and InputHandler.Modes.cs (unknown or unhandled modes, Meta/Alt/Win32 toggles), which log an int mode or a TerminalMode name, never stream text. BufferReflow.cs's Debug.Assert has no message. Nothing on the input-encoding side (Generate*Input, Paste, Kitty) logs anything.

Test

DiagnosticOutputTests adds a TraceListener for the test, removed in finally, and writes S3CR3T-sentinel through:

• an OSC with no number, OSC 9999, and an OSC whose number is the sentinel;
• OSC 52 (raw and base64), OSC 2 and OSC 8;
• a CSI with 32 intermediates;
• DCS, DECRQSS, APC and PM strings;
• Paste and GenerateCharInput.

It asserts that the sentinel, its base64 and the run of intermediates never appear. Under #if DEBUG it also asserts that the three redacted lines did arrive, so an empty capture can't pass. Restoring the raw OSC text turns it red, and so does lifting the CSI cap. It and the OSC, OSC passthrough, mode handling, private CSI dispatch and InputHandler tests pass 297/297. The full test project wasn't run.

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