[ViralBShah]

A broadcast whose function is not zero at the zeros returns a dense array, but it is computed by the sparse kernels, which store every entry in a sparse array with the index type of the arguments. When that index type cannot address every entry, the call throws although the dense result is representable.

S = sparse(Int8[1], Int8[1], [1.0], 12, 12)   # 144 entries, `Int8` indices
R = cos.(S)

Before

ERROR: InexactError: trunc(Int8, 133)

After

julia> typeof(R), R == cos.(Array(S))
(Matrix{Float64}, true)

_densenonzero now asks, from the promoted index type of the arguments and the shape of the result, whether that type addresses every entry, and otherwise hands the broadcast to _densebroadcast, as it already does for a Bool or non-concrete element type. The check is on a type and folds away, so cos.(A) for an Int-indexed matrix stays inferred as Matrix{Float64}; at 10^6 entries its time (2.0 ms) and allocations (16.0 MB) are the same as on main.

Left out: the in-place forms on the same matrix (S .= 1.0, map!), which fail for the same reason in a sparse destination and are a separate change.

Split from #1022. A bug fix with no change of result type, so a candidate for backporting.

Written by Claude Code.

🤖 Generated with Claude Code

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 94.79%. Comparing base (c0f75f0) to head (3a97dbb).
⚠️ Report is 6 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1086      +/-   ##
==========================================
+ Coverage   94.75%   94.79%   +0.03%     
==========================================
  Files          16       16              
  Lines        9885     9886       +1     
==========================================
+ Hits         9367     9371       +4     
+ Misses        518      515       -3     

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[ViralBShah]

Reviewed by Codex at 3a97dbb.

No actionable findings. Checking the promoted sparse index type against the broadcast result shape before entering the fully stored sparse kernel addresses the narrow-index failure; the fallback preserves the dense result container.