Understand the failure.
Verify the repair.
Small, reproducible software failures. The broken implementation, the fix that didn’t work, and the one that passed—preserved together.
Explore the cases ↓How results are verified ↗WHAT THE ARCHIVE CONTAINS
100840 executable cases. 20168 are open.
Every case records the implementation that fails, the fix that did not work, and the repair that passed its checks—with recorded outputs and source hashes. This release adds 100840 cases across 20168 failure mechanisms and 254 domains.
The open tier gives you the failure and the unsuccessful fix for one case in every mechanism. The remaining 80672 cases, 5 variants per mechanism, are member-only: the verified repair, its recorded checks, and the full fixture suite are held in the member archive. Read the methodology ↗
A RECORD OF WHAT WENT WRONG
Browse the archive / 100840
Douglas-Peucker simplification of a topology arc: sub-arc split bounds · case 01
Vertices right after a kept vertex are judged against the wrong base segment.
Douglas-Peucker simplification of a topology arc: sub-arc split bounds · case 02
Vertices right after a kept vertex are judged against the wrong base segment.
Douglas-Peucker simplification of a topology arc: sub-arc split bounds · case 03
Vertices right after a kept vertex are judged against the wrong base segment.
Douglas-Peucker simplification of a topology arc: sub-arc split bounds · case 04
Vertices right after a kept vertex are judged against the wrong base segment.
Douglas-Peucker simplification of a topology arc: sub-arc split bounds · case 05
Vertices right after a kept vertex are judged against the wrong base segment.
Douglas-Peucker simplification of a topology arc: first maximum tie-break · case 01
Among equally distant vertices the last one is kept, changing the simplified shape.
Douglas-Peucker simplification of a topology arc: first maximum tie-break · case 02
Among equally distant vertices the last one is kept, changing the simplified shape.
Douglas-Peucker simplification of a topology arc: first maximum tie-break · case 03
Among equally distant vertices the last one is kept, changing the simplified shape.
Douglas-Peucker simplification of a topology arc: first maximum tie-break · case 04
Among equally distant vertices the last one is kept, changing the simplified shape.
Douglas-Peucker simplification of a topology arc: first maximum tie-break · case 05
Among equally distant vertices the last one is kept, changing the simplified shape.
Sliver polygon detection by thinness ratio: hole area subtraction · case 01
Donut-shaped slivers look compact because hole area is added.
Sliver polygon detection by thinness ratio: hole area subtraction · case 02
Donut-shaped slivers look compact because hole area is added.
Sliver polygon detection by thinness ratio: hole area subtraction · case 03
Donut-shaped slivers look compact because hole area is added.
Sliver polygon detection by thinness ratio: hole area subtraction · case 04
Donut-shaped slivers look compact because hole area is added.
Sliver polygon detection by thinness ratio: hole area subtraction · case 05
Donut-shaped slivers look compact because hole area is added.
Sliver polygon detection by thinness ratio: hole perimeter · case 01
Thin rims around large holes are not flagged.
Sliver polygon detection by thinness ratio: hole perimeter · case 02
Thin rims around large holes are not flagged.
Sliver polygon detection by thinness ratio: hole perimeter · case 03
Thin rims around large holes are not flagged.
Sliver polygon detection by thinness ratio: hole perimeter · case 04
Thin rims around large holes are not flagged.
Sliver polygon detection by thinness ratio: hole perimeter · case 05
Thin rims around large holes are not flagged.
Sliver polygon detection by thinness ratio: exterior orientation · case 01
Clockwise polygons are always reported as degenerate.
Sliver polygon detection by thinness ratio: exterior orientation · case 02
Clockwise polygons are always reported as degenerate.
Sliver polygon detection by thinness ratio: exterior orientation · case 03
Clockwise polygons are always reported as degenerate.
Sliver polygon detection by thinness ratio: exterior orientation · case 04
Clockwise polygons are always reported as degenerate.
Sliver polygon detection by thinness ratio: exterior orientation · case 05
Clockwise polygons are always reported as degenerate.
Sliver polygon detection by thinness ratio: threshold strictness · case 01
Polygons exactly at the threshold are flagged as slivers.
Sliver polygon detection by thinness ratio: threshold strictness · case 02
Polygons exactly at the threshold are flagged as slivers.
Sliver polygon detection by thinness ratio: threshold strictness · case 03
Polygons exactly at the threshold are flagged as slivers.
Sliver polygon detection by thinness ratio: threshold strictness · case 04
Polygons exactly at the threshold are flagged as slivers.
Sliver polygon detection by thinness ratio: threshold strictness · case 05
Polygons exactly at the threshold are flagged as slivers.
Sliver polygon detection by thinness ratio: degenerate guard · case 01
Collapsed or fully-holed polygons get a negative or zero thinness and are reported as slivers.
Sliver polygon detection by thinness ratio: degenerate guard · case 02
Collapsed or fully-holed polygons get a negative or zero thinness and are reported as slivers.
Sliver polygon detection by thinness ratio: degenerate guard · case 03
Collapsed or fully-holed polygons get a negative or zero thinness and are reported as slivers.
Sliver polygon detection by thinness ratio: degenerate guard · case 04
Collapsed or fully-holed polygons get a negative or zero thinness and are reported as slivers.
Sliver polygon detection by thinness ratio: degenerate guard · case 05
Collapsed or fully-holed polygons get a negative or zero thinness and are reported as slivers.
Area-weighted centroid of a multipolygon with holes: hole weight · case 01
Centroids of polygons with holes move toward the hole.
Area-weighted centroid of a multipolygon with holes: hole weight · case 02
Centroids of polygons with holes move toward the hole.
Area-weighted centroid of a multipolygon with holes: hole weight · case 03
Centroids of polygons with holes move toward the hole.
Area-weighted centroid of a multipolygon with holes: hole weight · case 04
Centroids of polygons with holes move toward the hole.
Area-weighted centroid of a multipolygon with holes: hole weight · case 05
Centroids of polygons with holes move toward the hole.
Area-weighted centroid of a multipolygon with holes: orientation normalisation · case 01
Clockwise parts pull the centroid away instead of toward themselves.
Area-weighted centroid of a multipolygon with holes: orientation normalisation · case 02
Clockwise parts pull the centroid away instead of toward themselves.
Area-weighted centroid of a multipolygon with holes: orientation normalisation · case 03
Clockwise parts pull the centroid away instead of toward themselves.
Area-weighted centroid of a multipolygon with holes: orientation normalisation · case 04
Clockwise parts pull the centroid away instead of toward themselves.
Area-weighted centroid of a multipolygon with holes: orientation normalisation · case 05
Clockwise parts pull the centroid away instead of toward themselves.
Area-weighted centroid of a multipolygon with holes: multipart accumulation · case 01
The centroid of a multipolygon equals the centroid of its last part.
Area-weighted centroid of a multipolygon with holes: multipart accumulation · case 02
The centroid of a multipolygon equals the centroid of its last part.
Area-weighted centroid of a multipolygon with holes: multipart accumulation · case 03
The centroid of a multipolygon equals the centroid of its last part.
Area-weighted centroid of a multipolygon with holes: multipart accumulation · case 04
The centroid of a multipolygon equals the centroid of its last part.
Area-weighted centroid of a multipolygon with holes: multipart accumulation · case 05
The centroid of a multipolygon equals the centroid of its last part.
Area-weighted centroid of a multipolygon with holes: edge moment terms · case 01
Centroid x coordinates drift along the edge direction.
Area-weighted centroid of a multipolygon with holes: edge moment terms · case 02
Centroid x coordinates drift along the edge direction.
Area-weighted centroid of a multipolygon with holes: edge moment terms · case 03
Centroid x coordinates drift along the edge direction.
Area-weighted centroid of a multipolygon with holes: edge moment terms · case 04
Centroid x coordinates drift along the edge direction.
Area-weighted centroid of a multipolygon with holes: edge moment terms · case 05
Centroid x coordinates drift along the edge direction.
Coverage gap and overlap areas: interior containment · case 01
Rectangles that merely share an edge are reported as overlapping.
Coverage gap and overlap areas: interior containment · case 02
Rectangles that merely share an edge are reported as overlapping.
Coverage gap and overlap areas: interior containment · case 03
Rectangles that merely share an edge are reported as overlapping.
Coverage gap and overlap areas: interior containment · case 04
Rectangles that merely share an edge are reported as overlapping.
Coverage gap and overlap areas: interior containment · case 05
Rectangles that merely share an edge are reported as overlapping.
Coverage gap and overlap areas: overlap multiplicity · case 01
Triple overlaps are counted twice.
Coverage gap and overlap areas: overlap multiplicity · case 02
Triple overlaps are counted twice.
Coverage gap and overlap areas: overlap multiplicity · case 03
Triple overlaps are counted twice.
Coverage gap and overlap areas: overlap multiplicity · case 04
Triple overlaps are counted twice.
Coverage gap and overlap areas: overlap multiplicity · case 05
Triple overlaps are counted twice.
Coverage gap and overlap areas: extent clipping · case 01
Gaps and overlaps outside the study area are reported.
Coverage gap and overlap areas: extent clipping · case 02
Gaps and overlaps outside the study area are reported.
Coverage gap and overlap areas: extent clipping · case 03
Gaps and overlaps outside the study area are reported.
Coverage gap and overlap areas: extent clipping · case 04
Gaps and overlaps outside the study area are reported.
Coverage gap and overlap areas: extent clipping · case 05
Gaps and overlaps outside the study area are reported.
Coverage gap and overlap areas: extent breakpoints · case 01
Uncovered strips along the extent edge are missing from the gap total.
Coverage gap and overlap areas: extent breakpoints · case 02
Uncovered strips along the extent edge are missing from the gap total.
Coverage gap and overlap areas: extent breakpoints · case 03
Uncovered strips along the extent edge are missing from the gap total.
Coverage gap and overlap areas: extent breakpoints · case 04
Uncovered strips along the extent edge are missing from the gap total.
Coverage gap and overlap areas: extent breakpoints · case 05
Uncovered strips along the extent edge are missing from the gap total.
Shapefile part rings assembled into polygons: exterior winding convention · case 01
Every shapefile polygon comes out inside-out.
Shapefile part rings assembled into polygons: exterior winding convention · case 02
Every shapefile polygon comes out inside-out.
Shapefile part rings assembled into polygons: exterior winding convention · case 03
Every shapefile polygon comes out inside-out.
Shapefile part rings assembled into polygons: exterior winding convention · case 04
Every shapefile polygon comes out inside-out.
Shapefile part rings assembled into polygons: exterior winding convention · case 05
Every shapefile polygon comes out inside-out.
Shapefile part rings assembled into polygons: smallest containing exterior · case 01
Holes in islands inside lakes are attached to the outer mainland ring.
Shapefile part rings assembled into polygons: smallest containing exterior · case 02
Holes in islands inside lakes are attached to the outer mainland ring.
Shapefile part rings assembled into polygons: smallest containing exterior · case 03
Holes in islands inside lakes are attached to the outer mainland ring.
Shapefile part rings assembled into polygons: smallest containing exterior · case 04
Holes in islands inside lakes are attached to the outer mainland ring.
Shapefile part rings assembled into polygons: smallest containing exterior · case 05
Holes in islands inside lakes are attached to the outer mainland ring.
Shapefile part rings assembled into polygons: orphan hole promotion · case 01
Holes with no enclosing exterior vanish from the output.
Shapefile part rings assembled into polygons: orphan hole promotion · case 02
Holes with no enclosing exterior vanish from the output.
Shapefile part rings assembled into polygons: orphan hole promotion · case 03
Holes with no enclosing exterior vanish from the output.
Shapefile part rings assembled into polygons: orphan hole promotion · case 04
Holes with no enclosing exterior vanish from the output.
Shapefile part rings assembled into polygons: orphan hole promotion · case 05
Holes with no enclosing exterior vanish from the output.
Shapefile part rings assembled into polygons: containment test · case 01
Holes in the notch of an L-shaped parcel are attached to that parcel.
Shapefile part rings assembled into polygons: containment test · case 02
Holes in the notch of an L-shaped parcel are attached to that parcel.
Shapefile part rings assembled into polygons: containment test · case 03
Holes in the notch of an L-shaped parcel are attached to that parcel.
Shapefile part rings assembled into polygons: containment test · case 04
Holes in the notch of an L-shaped parcel are attached to that parcel.
Shapefile part rings assembled into polygons: containment test · case 05
Holes in the notch of an L-shaped parcel are attached to that parcel.
Shapefile part rings assembled into polygons: output exterior ordering · case 01
Promoted orphan rings appear after all regular exteriors regardless of their index.
Shapefile part rings assembled into polygons: output exterior ordering · case 02
Promoted orphan rings appear after all regular exteriors regardless of their index.
Shapefile part rings assembled into polygons: output exterior ordering · case 03
Promoted orphan rings appear after all regular exteriors regardless of their index.
Shapefile part rings assembled into polygons: output exterior ordering · case 04
Promoted orphan rings appear after all regular exteriors regardless of their index.
Shapefile part rings assembled into polygons: output exterior ordering · case 05
Promoted orphan rings appear after all regular exteriors regardless of their index.
INSPECTABLE BY DESIGN
Every result has a runnable source.
Runnable implementations with recorded outputs, source hashes, and explicit contracts. Related variants share a failure mechanism and belong together in evaluation splits.
Read the methodology ↗