Wrong evaluation in sparse/higherorderfns.jl fix#23857 (#24806)

* wrong evaluation in sparse/higherorderfns.jl fix#23857

* `_broadcast_nonzeropre` fixed all branches of if-statement

Author: KlausC

stdlib/SparseArrays/src/higherorderfns.jl

@@ -688,7 +688,7 @@ function _broadcast_notzeropres!(f::Tf, fillvalue, C::SparseVecOrMat, A::SparseV
             Bk, stopBk = numcols(B) == 1 ? (colstartind(B, 1), colboundind(B, 1)) : (colstartind(B, j), colboundind(B, j))
             Ax = Ak < stopAk ? storedvals(A)[Ak] : zero(eltype(A))
             fvAzB = f(Ax, zero(eltype(B)))
-            if _iszero(fvAzB)
+            if fvAzB == fillvalue
                 while Bk < stopBk
                     Cx = f(Ax, storedvals(B)[Bk])
                     Cx != fillvalue && (storedvals(C)[jo + storedinds(B)[Bk]] = Cx)
@@ -713,7 +713,7 @@ function _broadcast_notzeropres!(f::Tf, fillvalue, C::SparseVecOrMat, A::SparseV
             Bk, stopBk = numcols(B) == 1 ? (colstartind(B, 1), colboundind(B, 1)) : (colstartind(B, j), colboundind(B, j))
             Bx = Bk < stopBk ? storedvals(B)[Bk] : zero(eltype(B))
             fzAvB = f(zero(eltype(A)), Bx)
-            if _iszero(fzAvB)
+            if fzAvB == fillvalue
                 while Ak < stopAk
                     Cx = f(storedvals(A)[Ak], Bx)
                     Cx != fillvalue && (storedvals(C)[jo + storedinds(A)[Ak]] = Cx)

stdlib/SparseArrays/test/higherorderfns.jl

@@ -215,8 +215,21 @@ end
             end
         end
     end
+
+    # fix#23857
+    @test sparse([1; 0]) ./ [1] == sparse([1.0; 0.0])
+    @test isequal(sparse([1 2; 1 0]) ./ [1; 0], sparse([1.0 2; Inf NaN]))
+    @test sparse([1  0]) ./ [1] == sparse([1.0 0.0])
+    @test isequal(sparse([1 2; 1 0]) ./ [1 0], sparse([1.0 Inf; 1 NaN]))
+
+    @test sparse([1]) .\ sparse([1; 0]) == sparse([1.0; 0.0])
+    @test isequal(sparse([1; 0]) .\ sparse([1 2; 1 0]), sparse([1.0 2; Inf NaN]))
+    @test sparse([1]) .\ sparse([1  0]) == sparse([1.0 0.0])
+    @test isequal(sparse([1 0]) .\ sparse([1 2; 1 0]), sparse([1.0 Inf; 1 NaN]))
+
 end
 
+
 @testset "broadcast[!] implementation capable of handling >2 (input) sparse vectors/matrices" begin
     N, M, p = 10, 12, 0.3
     f(x, y, z) = x + y + z + 1