[REPL] more reliable extension loading

base/loading.jl

@@ -2715,7 +2715,7 @@
 
 # load a serialized file directly from append_bundled_depot_path for uuidkey without stalechecks
 """
-    require_stdlib(package_uuidkey::PkgId, ext::Union{Nothing, String}=nothing)
+    require_stdlib(package_uuidkey::PkgId, [ext::String, from::Module])
 
 !!! warning "May load duplicate copies of stdlib packages."
 
@@ -2754,7 +2754,8 @@
       [1] https://github.com/JuliaLang/Pkg.jl/issues/4017#issuecomment-2377589989
       [2] https://github.com/JuliaLang/StyledStrings.jl/issues/91#issuecomment-2379602914
 """
-function require_stdlib(package_uuidkey::PkgId, ext::Union{Nothing, String}=nothing)
+require_stdlib(package_uuidkey::PkgId) = require_stdlib(package_uuidkey, nothing, Base)
+function require_stdlib(package_uuidkey::PkgId, ext::Union{Nothing, String}, from::Module)
     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.")
@@ -2766,15 +2767,29 @@
     newm = start_loading(this_uuidkey, UInt128(0), true)
     newm === nothing || return newm
     try
-        # first since this is a stdlib, try to look there directly first
-        if ext === nothing
-            sourcepath = normpath(env, this_uuidkey.name, "src", this_uuidkey.name * ".jl")
-        else
-            sourcepath = find_ext_path(normpath(joinpath(env, package_uuidkey.name)), ext)
-        end
         depot_path = append_bundled_depot_path!(empty(DEPOT_PATH))
-        set_pkgorigin_version_path(this_uuidkey, sourcepath)
-        newm = _require_search_from_serialized(this_uuidkey, sourcepath, UInt128(0), false; DEPOT_PATH=depot_path)
+        from_stdlib = true # set to false if `from` is a normal package so we do not want the internal loader for the extension either
+        if ext isa String
+            from_uuid = PkgId(from)
+            from_m = get(loaded_modules, from_uuid, nothing)
+            if from_m === from
+                # if from_uuid is either nothing or points to something else, assume we should use require_stdlib
+                # otherwise check cachepath for from to see if it looks like it is from depot_path, since try_build_ids
+                cachepath = get(PkgOrigin, pkgorigins, from_uuid).cachepath
+                entrypath, entryfile = cache_file_entry(from_uuid)
+                from_stdlib = any(x -> startswith(entrypath, x), depot_path)
+            end
+        end
+        if from_stdlib
+            # first since this is a stdlib, try to look there directly first
+            if ext === nothing
+                sourcepath = normpath(env, this_uuidkey.name, "src", this_uuidkey.name * ".jl")
+            else
+                sourcepath = find_ext_path(normpath(joinpath(env, package_uuidkey.name)), ext)
+            end
+            set_pkgorigin_version_path(this_uuidkey, sourcepath)
+            newm = _require_search_from_serialized(this_uuidkey, sourcepath, UInt128(0), false; DEPOT_PATH=depot_path)
+        end
     finally
         end_loading(this_uuidkey, newm)
     end
@@ -2784,10 +2799,12 @@
         run_package_callbacks(this_uuidkey)
     else
         # if the user deleted their bundled depot, next try to load it completely normally
+        # if it is an extension, we first need to indicate where to find its parant via EXT_PRIMED
+        ext isa String && (EXT_PRIMED[this_uuidkey] = PkgId[package_uuidkey])
         newm = _require_prelocked(this_uuidkey)
     end
     return newm
-    end
+    end # release lock
 end
 
 # relative-path load

stdlib/REPL/src/Pkg_beforeload.jl

@@ -1,7 +1,9 @@
+# This file is a part of Julia. License is MIT: https://julialang.org/license
+
 ## Pkg stuff needed before Pkg has loaded
 
 const Pkg_pkgid = Base.PkgId(Base.UUID("44cfe95a-1eb2-52ea-b672-e2afdf69b78f"), "Pkg")
-load_pkg() = Base.require_stdlib(Pkg_pkgid, "REPLExt")
+load_pkg() = Base.require_stdlib(Pkg_pkgid, "REPLExt", REPL)
 
 ## Below here copied/tweaked from Pkg Types.jl so that the dummy Pkg prompt
 # can populate the env correctly before Pkg loads