Drop support for Julia 1.6

.buildkite/pipeline.yml

@@ -1,8 +1,8 @@
 steps:
-  - label: "GPU integration - julia v1.6"
+  - label: "GPU integration - julia v1.10"
     plugins:
       - JuliaCI/julia#v1:
-          version: "1.6"
+          version: "1.10"
       - JuliaCI/julia-test#v1: ~
     command:
       - mkdir -p "$${JULIA_DEPOT_PATH}/conda/3/x86_64"

.github/workflows/Downstream.yml

@@ -1,4 +1,4 @@
-  
+
 name: IntegrationTest
 on:
   push:
@@ -25,7 +25,6 @@ jobs:
           - {user: SciML, repo: DiffEqFlux.jl, group: Layers}
           - {user: SciML, repo: DiffEqFlux.jl, group: BasicNeuralDE}
           - {user: SciML, repo: NeuralPDE.jl, group: NNPDE}
-          - {user: JuliaMolSim, repo: Molly.jl, group: Zygote}
     steps:
       - uses: actions/checkout@v3
       - uses: julia-actions/setup-julia@v1

.github/workflows/ci.yml

@@ -17,7 +17,7 @@ jobs:
       fail-fast: false
       matrix:
         version:
-          - '1.6' # Replace this with the minimum Julia version that your package supports.
+          - '1.10' # Replace this with the minimum Julia version that your package supports.
           - '1'   # automatically expands to the latest stable 1.x release of Julia
           - 'nightly'
         os:

Project.toml

@@ -58,7 +58,7 @@ SpecialFunctions = "1.6, 2"
 Statistics = "1"
 Tracker = "0.2"
 ZygoteRules = "0.2.5"
-julia = "1.6"
+julia = "1.10"
 
 [extras]
 CUDA = "052768ef-5323-5732-b1bb-66c8b64840ba"

src/Zygote.jl

@@ -79,10 +79,6 @@ macro profile(ex)
 end
 
 using PrecompileTools
-# This caused freezes on early 1.8 patch versions,
-# see https://github.com/SciML/DiffEqFlux.jl/issues/783
-@static if VERSION < v"1.8" || VERSION >= v"1.8.5"
   @compile_workload precompile()
-end
 
 end # module

src/compiler/interface2.jl

@@ -31,10 +31,6 @@ function _generate_pullback(ctx, world, f, args...)
   g = try
     _generate_pullback_via_decomposition(T, world)
   catch e
-    if VERSION < v"1.8"
-      # work around Julia bug
-      rethrow(CompileError(T,e))
-    end
     return :(throw($(CompileError(T,e))))
   end
   g === nothing && return :(f(args...), Pullback{$T}((f,)))
@@ -53,10 +49,6 @@ function _generate_callable_pullback(j::Type{<:Pullback{T}}, world, Δ) where T
   g = try
     _generate_pullback_via_decomposition(T, world)
   catch e
-    if VERSION < v"1.8"
-      # work around Julia bug
-      rethrow(CompileError(T,e))
-    end
     return :(throw($(CompileError(T,e))))
   end
   if g === nothing

src/lib/lib.jl

@@ -1,13 +1,5 @@
 using Base: RefValue
-
-if VERSION > v"1.7.0-DEV.204"
-  using Base: ismutabletype
-else
-  function ismutabletype(@nospecialize(t::Type))
-    t = Base.unwrap_unionall(t)
-    return isa(t, DataType) && t.mutable
-  end
-end
+using Base: ismutabletype
 
 # Interfaces
 
@@ -87,12 +79,7 @@ unwrap(ref, x) = x
 end
 
 function global_set(ref, val)
-  @static if VERSION < v"1.9.0-DEV.265"
-    ccall(:jl_set_global, Cvoid, (Any, Any, Any),
-          ref.mod, ref.name, val)
-  else
     setglobal!(ref.mod, ref.name, val)
-  end
 end
 
 @_adjoint_keepthunks! function global_set(ref, x)

src/lib/literal_getproperty.jl

@@ -29,11 +29,7 @@ function reflect(@nospecialize(sigtypes::Tuple), world::UInt)
     end
     method_index === 0 && return nothing
     type_signature, raw_static_params, method = _methods[method_index]
-    if VERSION < v"1.8-"
-        method_instance = Core.Compiler.specialize_method(method, type_signature, raw_static_params, false)
-    else
-        method_instance = Core.Compiler.specialize_method(method, type_signature, raw_static_params; preexisting=false)
-    end
+    method_instance = Core.Compiler.specialize_method(method, type_signature, raw_static_params; preexisting=false)
     method_signature = method.sig
     static_params = Any[raw_static_params...]
     return method_instance, method_signature, static_params
@@ -47,11 +43,7 @@ function _generate_literal_getproperty(ctx, world, x, ::Type{Val{f}}) where f
     sig(x) = Tuple{x, typeof(f)}
     rrule_sig(x) = Tuple{typeof(getproperty), x, typeof(f)}
     pb_sig(x) = Tuple{ctx, typeof(getproperty), x, typeof(f)}
-    @static if VERSION >= v"1.10.0-DEV.65"
-        which(f, t) = Base._which(Base.signature_type(f, t); world).method
-    else
-        which(f, t) = Base.which(f, t)
-    end
+    which(f, t) = Base._which(Base.signature_type(f, t); world).method
 
     # either `getproperty` has a custom implementation or `_pullback(ctx, getproperty, x, f)`
     # / `rrule(getproperty, x, f) is overloaded directly
@@ -62,11 +54,7 @@ function _generate_literal_getproperty(ctx, world, x, ::Type{Val{f}}) where f
     if is_getfield_fallback
         # just copy pullback of `literal_getfield`
         mi, _sig, sparams = reflect((typeof(_pullback), ctx, typeof(literal_getfield), x, Val{f}), world)
-        ci = if VERSION >= v"1.10.0-DEV.873"
-            copy(Core.Compiler.retrieve_code_info(mi, world))
-        else
-            copy(Core.Compiler.retrieve_code_info(mi))
-        end
+        ci = copy(Core.Compiler.retrieve_code_info(mi, world))
 
         # we need to change the second arg to `_pullback` from `literal_getproperty` to
         # `literal_getfield`
@@ -100,7 +88,6 @@ function _generate_literal_getproperty(ctx, world, x, ::Type{Val{f}}) where f
     end
 end
 
-if VERSION >= v"1.10.0-DEV.873"
 
 # on Julia 1.10, generated functions need to keep track of the world age
 
@@ -116,11 +103,3 @@ end
   $(Expr(:meta, :generated, _literal_getproperty_pullback_generator))
   $(Expr(:meta, :generated_only))
 end
-
-else
-
-@generated function _pullback(ctx::AContext, ::typeof(literal_getproperty), x, f)
-    _generate_literal_getproperty(ctx, nothing, x, f)
-end
-
-end

test/compiler.jl

@@ -33,11 +33,7 @@ y, back = pullback(badly, 2)
 bt = try back(1) catch e stacktrace(catch_backtrace()) end
 
 @test trace_contains(bt, nothing, "compiler.jl", bad_def_line)
-if VERSION >= v"1.10-"
-  @test trace_contains(bt, :badly, "compiler.jl", bad_call_line)
-else
-  @test_broken trace_contains(bt, :badly, "compiler.jl", bad_call_line)
-end
+@test trace_contains(bt, :badly, "compiler.jl", bad_call_line)
 
 # Type inference checks
 
@@ -178,12 +174,11 @@ end
     @test y_explicit == y_implicit == getfield(g, :m)
 
     ∇args = ((m = [1.0, 0.0, 0.0], P = nothing),)
-    if VERSION > v"1.7-"
       # This type instability is due to the handling of non-bitstypes in `accum_param`
       @test Base.return_types(back_implicit, Tuple{Vector{Float64}}) == Any[Union{Tuple{Nothing}, typeof(∇args)}]
       # But the same should infer if implicit parameters are disabled
       @test Base.return_types(back_explicit, Tuple{Vector{Float64}}) == Any[typeof(∇args)]
-    end
+
     @test back_explicit([1., 0, 0]) == back_implicit([1., 0, 0]) == ∇args
 
     Base.getproperty(g::Gaussian, s::Symbol) = 2getfield(g, s)
@@ -282,9 +277,6 @@ function try_catch_finally(cond, x)
     x
 end
 
-if VERSION >= v"1.8"
-    # try/catch/else is invalid syntax prior to v1.8
-    eval(Meta.parse("""
         function try_catch_else(cond, x)
             x = 2x
 
@@ -299,8 +291,6 @@ if VERSION >= v"1.8"
 
             x
         end
-    """))
-end
 
 @testset "try/catch" begin
     @testset "happy path (nothrow)" begin
@@ -326,12 +316,10 @@ end
         end
     end
 
-    if VERSION >= v"1.8"
         @testset "try/catch/else" begin
             @test Zygote.gradient(try_catch_else, false, 1.0) == (nothing, 8.0)
             @test_throws ErrorException Zygote.gradient(try_catch_else, true, 1.0)
         end
-    end
 
     function foo_try(f)
       y = 1