precompile: add error for using require_stdlib during precompile (Jul…

…iaLang#56233)

This function could accidentally add a dependency on the stdlib in the
user's package, which would make it immediately stale. As pointed out to
me by topolarity

base/loading.jl

@@ -1564,7 +1564,6 @@ function _insert_extension_triggers(parent::PkgId, extensions::Dict{String, Any}
     end
 end
 
-precompiling_package::Bool = false
 loading_extension::Bool = false
 precompiling_extension::Bool = false
 function run_extension_callbacks(extid::ExtensionId)
@@ -2288,11 +2287,6 @@ For more details regarding code loading, see the manual sections on [modules](@r
 [parallel computing](@ref code-availability).
 """
 function require(into::Module, mod::Symbol)
-    if into === Base.__toplevel__ && precompiling_package
-        # this error type needs to match the error type compilecache throws for non-125 errors.
-        error("`using/import $mod` outside of a Module detected. Importing a package outside of a module \
-         is not allowed during package precompilation.")
-    end
     if _require_world_age[] != typemax(UInt)
         Base.invoke_in_world(_require_world_age[], __require, into, mod)
     else
@@ -2301,6 +2295,10 @@ function require(into::Module, mod::Symbol)
 end
 
 function __require(into::Module, mod::Symbol)
+    if into === Base.__toplevel__ && generating_output(#=incremental=#true)
+        error("`using/import $mod` outside of a Module detected. Importing a package outside of a module \
+         is not allowed during package precompilation.")
+    end
     @lock require_lock begin
     LOADING_CACHE[] = LoadingCache()
     try
@@ -2709,6 +2707,10 @@ end
       [2] https://github.com/JuliaLang/StyledStrings.jl/issues/91#issuecomment-2379602914
 """
 function require_stdlib(package_uuidkey::PkgId, ext::Union{Nothing, String}=nothing)
+    if generating_output(#=incremental=#true)
+        # Otherwise this would lead to awkward dependency issues by loading a package that isn't in the Project/Manifest
+        error("This interactive function requires a stdlib to be loaded, and package code should instead use it directly from that stdlib.")
+    end
     @lock require_lock begin
     # the PkgId of the ext, or package if not an ext
     this_uuidkey = ext isa String ? PkgId(uuid5(package_uuidkey.uuid, ext), ext) : package_uuidkey
@@ -3048,7 +3050,6 @@ function create_expr_cache(pkg::PkgId, input::String, output::String, output_o::
         empty!(Base.EXT_DORMITORY) # If we have a custom sysimage with `EXT_DORMITORY` prepopulated
         Base.track_nested_precomp($precomp_stack)
         Base.precompiling_extension = $(loading_extension | isext)
-        Base.precompiling_package = true
         Base.include_package_for_output($(pkg_str(pkg)), $(repr(abspath(input))), $(repr(depot_path)), $(repr(dl_load_path)),
             $(repr(load_path)), $deps, $(repr(source_path(nothing))))
         """)