Allow non-Function args to retry (#30382)

I hit this while trying to use a `PyObject`

NEWS.md

@@ -33,10 +33,11 @@ New library functions
 Standard library changes
 ------------------------
 
-  * The `extrema` function now accepts a function argument in the same manner as `minimum` and
-    `maximum` ([#30323]).
-  * `hasmethod` can now check for matching keyword argument names ([#30712]).
-  * `startswith` and `endswith` now accept a `Regex` for the second argument ([#29790]).
+* The `extrema` function now accepts a function argument in the same manner as `minimum` and
+  `maximum` ([#30323]).
+* `hasmethod` can now check for matching keyword argument names ([#30712]).
+* `startswith` and `endswith` now accept a `Regex` for the second argument ([#29790]).
+* `retry` supports arbitrary callable objects ([#30382]).
 
 #### LinearAlgebra
 
@@ -86,6 +87,7 @@ Deprecated or removed
 [#30323]: https://github.com/JuliaLang/julia/issues/30323
 [#30349]: https://github.com/JuliaLang/julia/issues/30349
 [#30372]: https://github.com/JuliaLang/julia/issues/30372
+[#30382]: https://github.com/JuliaLang/julia/issues/30382
 [#30583]: https://github.com/JuliaLang/julia/issues/30583
 [#30584]: https://github.com/JuliaLang/julia/issues/30584
 [#30593]: https://github.com/JuliaLang/julia/issues/30593

base/error.jl

@@ -221,13 +221,16 @@ length(ebo::ExponentialBackOff) = ebo.n
 eltype(::Type{ExponentialBackOff}) = Float64
 
 """
-    retry(f::Function;  delays=ExponentialBackOff(), check=nothing) -> Function
+    retry(f;  delays=ExponentialBackOff(), check=nothing) -> Function
 
 Return an anonymous function that calls function `f`.  If an exception arises,
 `f` is repeatedly called again, each time `check` returns `true`, after waiting the
 number of seconds specified in `delays`.  `check` should input `delays`'s
 current state and the `Exception`.
 
+!!! compat "Julia 1.2"
+    Before Julia 1.2 this signature was restricted to `f::Function`.
+
 # Examples
 ```julia
 retry(f, delays=fill(5.0, 3))
@@ -237,7 +240,7 @@ retry(http_get, check=(s,e)->e.status == "503")(url)
 retry(read, check=(s,e)->isa(e, IOError))(io, 128; all=false)
 ```
 """
-function retry(f::Function;  delays=ExponentialBackOff(), check=nothing)
+function retry(f;  delays=ExponentialBackOff(), check=nothing)
     (args...; kwargs...) -> begin
         y = iterate(delays)
         while y !== nothing

test/error.jl

@@ -77,4 +77,7 @@ end
     foo_kwargs(x; y=5) = x + y
     @test retry(foo_kwargs)(3) == 8
     @test retry(foo_kwargs)(3; y=4) == 7
+
+    # non-Functions
+    @test retry(Float64)(1) === 1.0
 end