fix(clipboard): neutralize termflow OSC 52 clipboard hijacking at the source#484
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termflow's RenderFeatures.clipboard defaults to True, causing it to emit OSC 52 escape sequences that silently overwrite the user's clipboard with every rendered code block. The patch replaces Renderer._copy_to_clipboard with a no-op to prevent this behavior at the source, ensuring robust protection regardless of per-call feature flags or future code paths. - Add patch_termflow_clipboard() to monkey-patch Renderer._copy_to_clipboard as a no-op - Integrate the patch into apply_all_patches() for automatic activation - Update module docstring to reflect broader third-party library patching scope - Ensure all changes are idempotent and fail silently if dependencies are absent
- Verify that _copy_to_clipboard is a no-op and produces no output - End-to-end test confirming no OSC 52 escape sequences appear in rendered output - Guard against crashes when termflow is not installed
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Problem
termflow's
RenderFeatures.clipboarddefaults toTrue. When the rendererfinishes a code block, it emits an OSC 52 escape sequence
(
\x1b]52;c;<base64>\x07) that modern terminals (iTerm2, Kitty, Alacritty,WezTerm, tmux) silently interpret as a clipboard-write command — clobbering
whatever the user had copied, with no prompt or consent.
PR #335 added explicit
RenderFeatures(clipboard=False)at the two knownTermflowRendererinstantiation sites, but this is whack-a-mole: any futurecode path, a new termflow version with changed defaults, or a missed
instantiation site reintroduces the bug.
Fix
Added
patch_termflow_clipboard()topydantic_patches.py. It replacestermflow.render.renderer.Renderer._copy_to_clipboardwith a no-op atstartup (via the existing
apply_all_patches()call incli_runner.py).This kills the behaviour at the source regardless of:
RenderFeatures(clipboard=...)flags~/.config/termflow/config.toml)The existing per-site
clipboard=Falseflags are left in place asdefense-in-depth and for documentation value.
Testing
test_copy_to_clipboard_is_noop— confirms the patched method writes nothingtest_code_block_render_emits_no_osc52— end-to-end: renders a code blockwith
clipboard=Trueand asserts no\x1b]52sequence leaks into outputtest_patch_does_not_crash_without_termflow— verifies graceful failure iftermflow is not installed
All 26 tests in
test_pydantic_patches_full_coverage.pypass.Files Changed
code_puppy/pydantic_patches.pypatch_termflow_clipboard()no-op patch, registered inapply_all_patches()tests/test_pydantic_patches_full_coverage.pyTestPatchTermflowClipboardclass with 3 regression tests