Fix scrolling issues with escape

[brrock]

fixes #344

Summary by CodeRabbit

• New Features

  • Added "Scroll escape sequence filter" — a new configurable toggle (off by default) to remove problematic terminal escape sequences and prevent unwanted scrolling; available in Misc settings and via config.

• Documentation

  • README and changelog updated with feature description, UI example, and config usage.

[coderabbitai]

📝 Walkthrough

Walkthrough

Adds a configurable filter to strip terminal escape sequences that cause unwanted console scrolling; includes a new patch implementation, settings/type additions, UI toggle, and documentation/changelog updates.

Changes

Cohort / File(s)	Summary
Configuration & Types src/defaultSettings.ts, src/types.ts	Added filterScrollEscapeSequences: boolean to default settings and MiscConfig (default false).
Patch Implementation src/patches/scrollEscapeSequenceFilter.ts, src/patches/index.ts	New patch writer writeScrollEscapeSequenceFilter implemented and registered as filter-scroll-escape-sequences; patch registered conditionally on the new setting.
UI Integration src/ui/components/MiscView.tsx	Inserted a boolean toggle in MiscView to control settings.misc.filterScrollEscapeSequences.
Documentation & Changelog README.md, CHANGELOG.md	Documented the "Scroll escape sequence filter" feature, UI/config examples, and added an Unreleased changelog entry.

Sequence Diagram(s)

(omitted)

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Possibly related PRs

• Misc fixes #440 — Modifies src/patches/index.ts and patch definitions; likely overlaps with patch registration changes in this PR.

Suggested reviewers

• bl-ue

Poem

🐰 Hopping through the terminal night,
I nibble escapes that cause a fright,
I tuck the scrolls and calm the screen,
A tidy console, neat and clean. 🥕✨

🚥 Pre-merge checks | ✅ 3 | ❌ 2

❌ Failed checks (1 warning, 1 inconclusive)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.
Title check	❓ Inconclusive	The title 'Fix scrolling issues with escape' is vague and incomplete; it mentions 'escape' without context, making it unclear that the fix addresses escape sequence filtering to prevent unwanted terminal scrolling.	Consider a more descriptive title like 'Add scroll escape sequence filter to prevent unwanted console scrolling' to clearly communicate the change.

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Linked Issues check	✅ Passed	The PR addresses the core objective of issue #344 by implementing a filter mechanism to prevent unwanted console scrolling caused by problematic ANSI escape sequences.
Out of Scope Changes check	✅ Passed	All changes are directly related to implementing the scroll escape sequence filter feature; no unrelated modifications are present in the PR.

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✨ Finishing touches

• 📝 Generate docstrings

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment

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No actionable comments were generated in the recent review. 🎉

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[coderabbitai]

Actionable comments posted: 2

🤖 Fix all issues with AI agents

In `@src/patches/scrollEscapeSequenceFilter.ts`:
- Around line 3-25: getScrollEscapeSequenceFilterLocation always returns a
number (0 or positive) so change its signature to return number (remove | null)
and update any caller that does an unnecessary null-check (e.g. the "index ===
null" check) to treat 0 as the valid injection point; alternatively, if you
prefer an explicit failure path, modify getScrollEscapeSequenceFilterLocation to
return null when no injection point is found (use -1 or a boolean flag to detect
failure) and keep callers expecting number | null—pick one approach and make the
return type and all callers (including the check against "index === null")
consistent with that choice.
- Around line 38-56: The injected stdout filter overrides process.stdout.write
(see _origStdoutWrite and the replacement function) but uses invalid/duplicate
ANSI patterns, duplicates escape forms, and coerces Buffers to strings; fix it
by only transforming when typeof chunk === 'string' (pass Buffers through
unchanged), remove redundant .replace calls for \x1b/\033/\u001b, and replace
the fragile patterns with proper CSI regexes such as /\x1b\[(?:\d+;?\d*)?H/g to
catch cursor-home variants (e.g. \x1b[H and \x1b[1;1H) and /\x1b\[\d*A/g to
catch cursor-up sequences (e.g. \x1b[A, \x1b[3A), then call _origStdoutWrite
with the original argument types and same encoding/cb parameters to preserve
binary and multi-byte correctness.

[bl-ue]

@brrock This is very cool!  Were you able to actually test that it works?

[brrock]

Yep I pasted some large text

[brrock]

@bl-ue

[bl-ue]

Okay, so I was confused about something. You're specifically fixing anthropics/claude-code#826, where the terminal scrolls around to different points when there's a very long session, but not the well known flickering issue like anthropics/claude-code#769 and anthropics/claude-code#1913, right?

[brrock]

Yes just one issue, I'm happy to fix the rest tho

[brrock]

@bl-ue

[bl-ue]

Yes just one issue, I'm happy to fix the rest tho

That would definitely be incredible. But please don't feel obligated!