pass warning state into nexted compilecache workers to conform warnings

Author: IanButterworth

base/loading.jl

@@ -1028,8 +1028,8 @@ function require(into::Module, mod::Symbol)
                                "future warnings for $(where.name) are suppressed.")
                     ) _module = nothing _file = nothing _group = nothing
                     push!(modules_warned_for, where)
+                    full_warning_showed[] = true
                 end
-                full_warning_showed[] = true
             end
         end
         if _track_dependencies[]
@@ -1393,6 +1393,8 @@ function create_expr_cache(pkg::PkgId, input::String, output::String, concrete_d
             "Base.PkgId(Base.UUID(\"$(_pkg.uuid)\"), $(repr(_pkg.name)))"
         end
     end
+    repr_modules_warned_for() = string("Base.PkgId[", join(pkg_str.(collect(Base.modules_warned_for)), ", "), "]")
+
     for (pkg, build_id) in concrete_deps
         push!(deps_strs, "$(pkg_str(pkg)) => $(repr(build_id))")
     end
@@ -1406,10 +1408,13 @@ function create_expr_cache(pkg::PkgId, input::String, output::String, concrete_d
                        $trace
                        --eval 'eval(Meta.parse(read(stdin,String)))'`, stderr = internal_stderr, stdout = internal_stdout),
               "w", stdout)
-    # write data over stdin to avoid the (unlikely) case of exceeding max command line size
+    # write data over stdin to avoid the (unlikely) case of exceeding max command line size.
+    # Pass warning state into workers to avoid excessive warnings from nested precompilation
+    # TODO: consider passing warning state back from workers also, so that warning state traverses the precompilation tree
     write(io.in, """
-        Base.include_package_for_output($(pkg_str(pkg)), $(repr(abspath(input))), $(repr(depot_path)), $(repr(dl_load_path)),
-            $(repr(load_path)), $deps, $(repr(source_path(nothing))))
+        Base.full_warning_showed[] = $(Base.full_warning_showed[]); (isempty($(repr_modules_warned_for())) || push!(
+            empty!(Base.modules_warned_for), $(repr_modules_warned_for())...)); Base.include_package_for_output($(pkg_str(pkg)),
+            $(repr(abspath(input))), $(repr(depot_path)), $(repr(dl_load_path)), $(repr(load_path)), $deps, $(repr(source_path(nothing))))
         """)
     close(io.in)
     return io