fix: surrogate pair (emoji) handling for a, r, s, ~, ga commands#9929
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fix: surrogate pair (emoji) handling for a, r, s, ~, ga commands#9929k1832 wants to merge 1 commit intoVSCodeVim:masterfrom
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`position.getRight()` increments by 1 UTF-16 code unit, but emojis outside the Basic Multilingual Plane are encoded as 2 code units (a surrogate pair). Moving by 1 code unit lands between the pair, and VSCode's `validatePosition` clamps it back to the start — so the cursor effectively goes backward. Add `getSurrogateAwareRight()`/`getSurrogateAwareLeft()` helpers on the Position prototype that skip past surrogate pairs, and use them in the affected commands: - `a` (Append): cursor now lands after the emoji - `r` (ReplaceCharacter): replaces the full emoji, not half - `s` (ChangeOperator): deletes the full emoji before entering insert - `~` (ToggleCase): advances past the emoji without corrupting it - `ga` (UnicodeInfo): shows full codepoint (e.g. U+1F604) via codePointAt() instead of the half-surrogate from charCodeAt() Commands already protected (no changes needed): x/X (DeleteOperator), l/h (MoveRight/MoveLeft), y (YankOperator).
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This was referenced Feb 10, 2026
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What this PR does / why we need it:
When the cursor is on a character encoded as a UTF-16 surrogate pair — emojis (
😄), rare CJK characters (𩸽), mathematical symbols (𝒟,𝔸), musical symbols (𝄞), etc. — several character-level commands break.position.getRight()increments by 1 UTF-16 code unit, but these characters are 2 code units. Moving by 1 lands between the pair, and VSCode'svalidatePositionclamps it back to the start — so the cursor effectively goes backward.a(Append)r(Replace)s(Change char)~(Toggle case)ga(Unicode info)Previous fixes addressed insert mode (PR #7977 / #6046) and motions (
l/h) and operators (x/X/y), but these 5 commands were missed. This PR completes the surrogate pair handling for character-level commands and adds 12 regression tests to prevent future breakage.Adds
getSurrogateAwareRight()/getSurrogateAwareLeft()helpers on the Position prototype that skip past surrogate pairs, following the same pattern already used byMoveRight(l) /MoveLeft(h). Uses these helpers in the 5 affected commands. Also switchesgafromcharCodeAt()tocodePointAt()to report the full Unicode codepoint.Which issue(s) this PR fixes
Fixes #9931
Partially addresses #8321 — this PR fixes
rand other character-level commands reported there. Remaining issues not addressed: easymotion uses raw character arithmetic for match positioning and marker decorations;xp(transpose) on surrogate pairs is also still broken (TODO added input.ts).Special notes for your reviewer: