When using a custom depot, still look in bundled directories.

base/initdefs.jl

@@ -86,9 +86,7 @@ See also [`JULIA_DEPOT_PATH`](@ref JULIA_DEPOT_PATH), and
 """
 const DEPOT_PATH = String[]
 
-function append_default_depot_path!(DEPOT_PATH)
-    path = joinpath(homedir(), ".julia")
-    path in DEPOT_PATH || push!(DEPOT_PATH, path)
+function append_bundled_depot_path!(DEPOT_PATH)
     path = abspath(Sys.BINDIR, "..", "local", "share", "julia")
     path in DEPOT_PATH || push!(DEPOT_PATH, path)
     path = abspath(Sys.BINDIR, "..", "share", "julia")
@@ -98,21 +96,26 @@ end
 
 function init_depot_path()
     empty!(DEPOT_PATH)
+    populated = false
+
     if haskey(ENV, "JULIA_DEPOT_PATH")
         str = ENV["JULIA_DEPOT_PATH"]
-        isempty(str) && return
         for path in eachsplit(str, Sys.iswindows() ? ';' : ':')
-            if isempty(path)
-                append_default_depot_path!(DEPOT_PATH)
-            else
-                path = expanduser(path)
-                path in DEPOT_PATH || push!(DEPOT_PATH, path)
-            end
+            isempty(path) && continue
+            path = expanduser(path)
+            path in DEPOT_PATH || push!(DEPOT_PATH, path)
+            populated = true
         end
-    else
-        append_default_depot_path!(DEPOT_PATH)
     end
-    nothing
+
+    if !populated
+        path = joinpath(homedir(), ".julia")
+        push!(DEPOT_PATH, path)
+    end
+
+    append_bundled_depot_path!(DEPOT_PATH)
+
+    return
 end
 
 ## LOAD_PATH & ACTIVE_PROJECT ##