check that the file being precompiled contains a module

base/loading.jl

@@ -2246,9 +2246,41 @@ function load_path_setup_code(load_path::Bool=true)
  return code
 end
 
+"""
+ check_src_module_wrap(srcpath::String)
+
+Checks that a package entry file `srcpath` has a module declaration, and that it is before any using/import statements.
+"""
+function check_src_module_wrap(pkg::PkgId, srcpath::String)
+ module_rgx = r"^\s*(?:@\w*\s*)*(?:bare)?module\s"
+ load_rgx = r"\b(?:using|import)\s"
+ load_seen = false
+ inside_comment = false
+ for s in eachline(srcpath)
+ if contains(s, "\"\"\"")
+ # ignore module docstrings
+ inside_comment = !inside_comment
+ end
+ inside_comment && continue
+ if startswith(s, module_rgx)
+ if load_seen
+ throw(ErrorException("Package $pkg source file $srcpath has a using/import before a module declaration."))
+ end
+ return true
+ end
+ if startswith(s, load_rgx)
+ load_seen = true
+ end
+ end
+ throw(ErrorException("Package $pkg source file $srcpath does not contain a module declaration."))
+end
+
 # this is called in the external process that generates precompiled package files
 function include_package_for_output(pkg::PkgId, input::String, depot_path::Vector{String}, dl_load_path::Vector{String}, load_path::Vector{String},
  concrete_deps::typeof(_concrete_dependencies), source::Union{Nothing,String})
+
+ check_src_module_wrap(pkg, input)
+
  append!(empty!(Base.DEPOT_PATH), depot_path)
  append!(empty!(Base.DL_LOAD_PATH), dl_load_path)
  append!(empty!(Base.LOAD_PATH), load_path)

test/loading.jl

@@ -1184,3 +1184,75 @@ end
  @test success(`$(Base.julia_cmd()) --startup-file=no -e 'using DelimitedFiles'`)
  @test success(`$(Base.julia_cmd()) --startup-file=no -e 'using Statistics'`)
 end
+
+@testset "checking srcpath modules" begin
+ p = Base.PkgId("Dummy")
+ fpath, _ = mktemp()
+ @testset "valid" begin
+ write(fpath, """
+ module Foo
+ using Bar
+ end
+ """)
+ @test Base.check_src_module_wrap(p, fpath)
+
+ write(fpath, """
+ baremodule Foo
+ using Bar
+ end
+ """)
+ @test Base.check_src_module_wrap(p, fpath)
+
+ write(fpath, """
+ \"\"\"
+ Foo
+ using Foo
+ \"\"\"
+ module Foo
+ using Bar
+ end
+ """)
+ @test Base.check_src_module_wrap(p, fpath)
+
+ write(fpath, """
+ # using foo
+ module Foo
+ using Bar
+ end
+ """)
+ @test Base.check_src_module_wrap(p, fpath)
+
+ write(fpath, """
+ # using foo
+ module Foo
+ using Bar
+ end
+ """)
+ @test Base.check_src_module_wrap(p, fpath)
+ end
+ @testset "invalid" begin
+ write(fpath, """
+ # module Foo
+ using Bar
+ # end
+ """)
+ @test_throws ErrorException Base.check_src_module_wrap(p, fpath)
+
+ write(fpath, """
+ using Bar
+ module Foo
+ end
+ """)
+ @test_throws ErrorException Base.check_src_module_wrap(p, fpath)
+
+ write(fpath, """
+ using Bar
+ """)
+ @test_throws ErrorException Base.check_src_module_wrap(p, fpath)
+
+ write(fpath, """
+ x = 1
+ """)
+ @test_throws ErrorException Base.check_src_module_wrap(p, fpath)
+ end
+end