From fd3396d592784ab0821d9183f82a5653cd998b84 Mon Sep 17 00:00:00 2001
From: Oliver Schulz <oschulz@mpp.mpg.de>
Date: Tue, 28 Mar 2023 10:17:15 +0200
Subject: [PATCH] Support Base.Broadcast.BroadcastFunction

---
 docs/src/index.md    |  2 +-
 src/inverse.jl       | 18 ++++++++++++++----
 test/test_inverse.jl | 10 ++++++++--
 3 files changed, 23 insertions(+), 7 deletions(-)

diff --git a/docs/src/index.md b/docs/src/index.md
index e1ff5b1..6d2c6b9 100644
--- a/docs/src/index.md
+++ b/docs/src/index.md
@@ -6,6 +6,6 @@ InverseFunctions
 
 This package defines the function [`inverse`](@ref). `inverse(f)` returns the inverse function of a function `f`, so that `inverse(f)(f(x)) ≈ x`.
 
-`inverse` supports mapped/broadcasted functions (via `Base.Fix1`) and (on Julia >=v1.6) function composition.
+`inverse` supports mapped/broadcasted functions (via `Base.Broadcast.BroadcastFunction` or `Base.Fix1`) and (on Julia >=v1.6) function composition.
 
 Implementations of `inverse(f)` for `identity`, `inv`, `adjoint` and `transpose` as well as for `exp`, `log`, `exp2`, `log2`, `exp10`, `log10`, `expm1`, `log1p` and `sqrt` are included.
diff --git a/src/inverse.jl b/src/inverse.jl
index ee3d1c6..67c4efa 100644
--- a/src/inverse.jl
+++ b/src/inverse.jl
@@ -5,8 +5,9 @@
 
 Return the inverse of function `f`.
 
-`inverse` supports mapped and broadcasted functions (via `Base.Fix1`) and
-function composition (requires Julia >= 1.6).
+`inverse` supports mapped and broadcasted functions (via
+`Base.Broadcast.BroadcastFunction` or `Base.Fix1`) and function composition
+(requires Julia >= 1.6).
 
 # Examples
 
@@ -27,7 +28,7 @@ true
 julia> inverse(inverse(foo)) === foo
 true
 
-julia> broadcast_foo = Base.Fix1(broadcast, foo);
+julia> broadcast_foo = VERSION >= v"1.6" ? Base.Broadcast.BroadcastFunction(foo) : Base.Fix1(broadcast, foo);
 
 julia> X = rand(10);
 
@@ -84,6 +85,15 @@ inverse(::typeof(inverse)) = inverse
             Base.ComposedFunction(inv_inner, inv_outer)
         end
     end
+
+    function inverse(bf::Base.Broadcast.BroadcastFunction)
+        inv_f_kernel = inverse(bf.f)
+        if inv_f_kernel isa NoInverse
+            NoInverse(bf)
+        else
+            Base.Broadcast.BroadcastFunction(inv_f_kernel)
+        end
+    end
 end
 
 function inverse(mapped_f::Base.Fix1{<:Union{typeof(map),typeof(broadcast)}})
@@ -91,7 +101,7 @@ function inverse(mapped_f::Base.Fix1{<:Union{typeof(map),typeof(broadcast)}})
     if inv_f_kernel isa NoInverse
         NoInverse(mapped_f)
     else
-        Base.Fix1(mapped_f.f, inverse(mapped_f.x))
+        Base.Fix1(mapped_f.f, inv_f_kernel)
     end
 end
 
diff --git a/test/test_inverse.jl b/test/test_inverse.jl
index a1a8687..0bd33f4 100644
--- a/test/test_inverse.jl
+++ b/test/test_inverse.jl
@@ -20,12 +20,18 @@ InverseFunctions.inverse(f::Bar) = Bar(inv(f.A))
 
 
 @testset "inverse" begin
+    @static if VERSION >= v"1.6"
+        _bc_func(f) = Base.Broadcast.BroadcastFunction(f)
+    else
+        _bc_func(f) = Base.Fix1(broadcast, f)
+    end
+
     f_without_inverse(x) = 1
     @test inverse(f_without_inverse) isa NoInverse
     @test_throws ErrorException inverse(f_without_inverse)(42)
     @test inverse(inverse(f_without_inverse)) === f_without_inverse
 
-    for f in (f_without_inverse ∘ exp, exp ∘ f_without_inverse, Base.Fix1(broadcast, f_without_inverse), Base.Fix1(map, f_without_inverse))
+    for f in (f_without_inverse ∘ exp, exp ∘ f_without_inverse, _bc_func(f_without_inverse), Base.Fix1(broadcast, f_without_inverse), Base.Fix1(map, f_without_inverse))
         @test inverse(f) == NoInverse(f)
         @test inverse(inverse(f)) == f
     end
@@ -96,7 +102,7 @@ InverseFunctions.inverse(f::Bar) = Bar(inv(f.A))
     end
 
     X = rand(5)
-    for f in (Base.Fix1(broadcast, foo), Base.Fix1(map, foo))
+    for f in (_bc_func(foo), Base.Fix1(broadcast, foo), Base.Fix1(map, foo))
         for x in (x, fill(x, 3), X)
             InverseFunctions.test_inverse(f, x)
         end