Add public to the @compat macro

Project.toml

@@ -1,6 +1,6 @@
 name = "Compat"
 uuid = "34da2185-b29b-5c13-b0c7-acf172513d20"
-version = "4.9.0"
+version = "4.10.0"
 
 [deps]
 Dates = "ade2ca70-3891-5945-98fb-dc099432e06a"

README.md

@@ -70,6 +70,8 @@ changes in `julia`.
 
 ## Supported features
 
+* `@compat public foo, bar` marks `foo` and `bar` as public in Julia 1.11+ and is a no-op in Julia 1.10 and earlier. ([#50105]) (since Compat 4.10.0)
+
 * `sort` for `NTuple` and other iterables. ([#46104]) (since Compat 4.9.0)
 
 * `redirect_stdio`, for simple stream redirection. ([#37978]) (since Compat 4.8.0)
@@ -172,3 +174,4 @@ Note that you should specify the correct minimum version for `Compat` in the
 [#43852]: https://github.com/JuliaLang/julia/issues/43852
 [#46104]: https://github.com/JuliaLang/julia/issues/46104
 [#48038]: https://github.com/JuliaLang/julia/issues/48038
+[#50105]: https://github.com/JuliaLang/julia/issues/50105

src/Compat.jl

@@ -389,7 +389,7 @@ end
 if VERSION < v"1.9.0-DEV.1163"
     import Base: IteratorSize, HasLength, HasShape, OneTo
     export stack
-    
+
     """
         stack(iter; [dims])
 

src/compatmacro.jl

@@ -13,11 +13,11 @@
     @static if VERSION < v"1.7.0-DEV.364"
         if Meta.isexpr(ex, :(=)) && Meta.isexpr(ex.args[1], :tuple) &&
             Meta.isexpr(ex.args[1].args[1], :parameters)
-            
+
             ex = _destructure_named_tuple(ex)
         end
     end
-    
+
     return Expr(ex.head, map(_compat, ex.args)...)
 end
 
@@ -39,3 +39,38 @@
     push!(ex.args, values)
     return ex
 end
+
+# https://github.com/JuliaLang/julia/pull/50105
+macro compat(public::Symbol, symbols_expr::Union{Expr, Symbol})
+    public == :public || throw(ArgumentError("Invalid Syntax: `@compat $public $symbols_expr`"))
+    symbols = _get_symbols(symbols_expr)
+    if VERSION >= v"1.11.0-DEV.469"
+        esc(Expr(:public, symbols...))
+    end
+end
+
+"""
+    _valid_macro(expr)
+
+Check if `expr` is a valid macro call with no arguments.
+"""
+_valid_macro(expr) = Meta.isexpr(expr, :macrocall) && length(expr.args) == 2 &&
+    expr.args[1] isa Symbol && string(expr.args[1])[1] == '@' &&
+    expr.args[2] isa LineNumberNode
+
+_get_symbols(symbol::Symbol) = [symbol]
+function _get_symbols(expr::Expr)
+    _valid_macro(expr) && return [expr.args[1]]
+    expr.head == :tuple || throw(ArgumentError("cannot mark `$expr` as public. Try `@compat public foo, bar`."))
+    symbols = Vector{Symbol}(undef, length(expr.args))
+    for (i, arg) in enumerate(expr.args)
+        if arg isa Symbol
+            symbols[i] = arg
+        elseif _valid_macro(arg)
+            symbols[i] = arg.args[1]
+        else
+            throw(ArgumentError("cannot mark `$arg` as public. Try `@compat public foo, bar`."))
+        end
+    end
+    symbols
+end

test/runtests.jl

@@ -238,7 +238,7 @@ end
 
 # https://github.com/JuliaLang/julia/pull/43852
 @testset "@assume_effects" begin
-    # ensure proper macro hygiene across versions 
+    # ensure proper macro hygiene across versions
     Compat.@assume_effects :total foo() = true
     Compat.@assume_effects bar() = true
     @test foo()
@@ -724,3 +724,33 @@ end
         @test_throws ArgumentError("1 cannot be sorted") sort(1)
     end
 end
+
+module Mod50105
+    using Compat
+    @compat public foo, var"#", baz
+    @compat public @mac1
+    @compat public f00, @mac2, @mac3
+    @compat public @mac4, @mac5
+end
+
+# https://github.com/JuliaLang/julia/pull/50105
+@testset "@compat public" begin
+    @compat public foo_50105
+    # foo_50105 = 4 # Uncommenting this line would cause errors due to https://github.com/JuliaLang/julia/issues/51325
+    @test Base.isexported(@__MODULE__, :foo_50105) === false
+    VERSION >= v"1.11.0-DEV.469" && @test Base.ispublic(@__MODULE__, :foo_50105)
+    for sym in [:foo, Symbol("#"), :baz, Symbol("@mac1"), :f00, Symbol("@mac2"), Symbol("@mac3"), Symbol("@mac4"), Symbol("@mac5")]
+        @test Base.isexported(Mod50105, sym) === false
+        VERSION >= v"1.11.0-DEV.469" && @test Base.ispublic(Mod50105, sym)
+    end
+
+    @test_throws LoadError @eval @compat public 4, bar
+    @test_throws LoadError @eval @compat public foo bar
+    @test_throws LoadError @eval @compat publac foo, bar
+    @test_throws LoadError @eval @compat public 4, @bar
+    @test_throws LoadError @eval @compat public foo @bar
+    @test_throws LoadError @eval @compat publac foo, @bar
+    @test_throws LoadError @eval @compat public @bar, 4
+    @test_throws LoadError @eval @compat public @bar foo
+    @test_throws LoadError @eval @compat publac @bar, foo
+end