fix(svg): reject malformed 'd' that loops forever after a Z#186
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A Z/z close command consumes no operands, so a stray non-command token after it (e.g. "M0 0 Z5") made the path scanner re-apply Z indefinitely, appending a close op every pass until the heap was exhausted — a DoS reachable from the @beta SvgPath.parse / SvgIcon public surface on a single malformed path string. Add a no-progress guard to the scan loop: if an iteration consumes neither a command letter nor an operand, fail with the usual position-carrying IllegalArgumentException instead of spinning. SvgPathTest gains a regression case wrapped in assertTimeoutPreemptively so the hang can never silently return.
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Why
Senior-review audit of the v1.8 SVG workstream surfaced a confirmed DoS in the
@BetaSVG path reader: aZ/zclose command consumes no operands, so a stray non-command token after it (e.g."M0 0 Z5") made the scanner re-applyZindefinitely, appending a close op to the ops list on every iteration until the heap was exhausted. Reachable from the publicSvgPath.parse/SvgIconsurface on a single malformed (or hostile) path string.What
SvgPathParsermain loop gains a no-progress guard: if an iteration consumes neither a command letter nor an operand, it fails with the usual position-carryingIllegalArgumentExceptioninstead of spinning. Generic — covers any operand-less command followed by a stray token, not justZ.SvgPathTest.strayTokenAfterCloseIsRejectedAndDoesNotHangpins it, wrapped inassertTimeoutPreemptively(2s)so the hang can never silently return.Tests
./mvnw test -Dtest=SvgPathTest -pl .→ 15/15, BUILD SUCCESS. Valid paths ("M0 0 Z","M0 0 Z Z", implicit repeats) unaffected.Lane: canonical /
document.svg(@beta). No public-surface change.