Fix VMobject.point_from_proportion crash on non-finite points#4854
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Chessing234 wants to merge 1 commit into
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Fix VMobject.point_from_proportion crash on non-finite points#4854Chessing234 wants to merge 1 commit into
Chessing234 wants to merge 1 commit into
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Non-finite points (e.g. a parametric function returning NaN) make every curve length NaN, so the length-accumulation loop never triggers and hits the internal 'Not sure how you reached here' exception (ManimCommunity#4838). Raise a clear ValueError for non-finite points, and fall back to the path endpoint for the alpha~=1 floating-point edge case. Co-authored-by: Cursor <cursoragent@cursor.com>
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Overview
Fixes #4838.
VMobject.point_from_proportioniterates over the curve pieces, accumulating arc lengths until it reachesalpha * total_length. When the mobject contains non-finite points (e.g. aParametricFunctionwhose callable returnsNaN), every length isNaN,target_lengthisNaN, and everycurrent_length + length >= target_lengthcomparison isFalse. The loop therefore completes without returning and hits the internal:which is confusing and points users at the tracker for their own data issue.
Fix
ValueErrorwhentarget_lengthis non-finite, naming the real cause (NaN/inf points).target_lengthmarginally past the accumulated lengths atalpha ≈ 1), return the path endpoint instead of raising.Test
Added
test_vmobject_point_from_proportion_non_finite_points, which reproduces the crash (a corner set toNaN) and asserts the descriptiveValueError.Made with Cursor