load Pkg when hitting Pkg repl history

Author: IanButterworth

stdlib/REPL/src/REPL.jl

@@ -717,7 +717,7 @@ function history_move(s::Union{LineEdit.MIState,LineEdit.PrefixSearchState}, his
         hist.last_mode = nothing
         hist.last_buffer = IOBuffer()
     else
-        if haskey(hist.mode_mapping, hist.modes[idx])
+        if haskey(hist.mode_mapping, hist.modes[idx]) || hist.modes[idx] == :pkg && !isnothing(load_pkg())
             LineEdit.transition(s, hist.mode_mapping[hist.modes[idx]]) do
                 LineEdit.replace_line(s, hist.history[idx])
             end
@@ -1130,25 +1130,23 @@ function setup_interface(
         end,
         ']' => function (s::MIState,o...)
             if isempty(s) || position(LineEdit.buffer(s)) == 0
-                pkgid = Base.PkgId(Base.UUID("44cfe95a-1eb2-52ea-b672-e2afdf69b78f"), "Pkg")
-                if Base.locate_package(pkgid) !== nothing # Only try load Pkg if we can find it
-                    Pkg = Base.require(pkgid)
-                    # Pkg should have loaded its REPL mode by now, let's find it so we can transition to it.
-                    pkg_mode = nothing
-                    for mode in repl.interface.modes
-                        if mode isa LineEdit.Prompt && mode.complete isa Pkg.REPLMode.PkgCompletionProvider
-                            pkg_mode = mode
-                            break
-                        end
+                Pkg = load_pkg()
+                Pkg === nothing && return
+                # Pkg should have loaded its REPL mode by now, let's find it so we can transition to it.
+                pkg_mode = nothing
+                for mode in repl.interface.modes
+                    if mode isa LineEdit.Prompt && mode.complete isa Pkg.REPLMode.PkgCompletionProvider
+                        pkg_mode = mode
+                        break
                     end
-                    # TODO: Cache the `pkg_mode`?
-                    if pkg_mode !== nothing
-                        buf = copy(LineEdit.buffer(s))
-                        transition(s, pkg_mode) do
-                            LineEdit.state(s, pkg_mode).input_buffer = buf
-                        end
-                        return
+                end
+                # TODO: Cache the `pkg_mode`?
+                if pkg_mode !== nothing
+                    buf = copy(LineEdit.buffer(s))
+                    transition(s, pkg_mode) do
+                        LineEdit.state(s, pkg_mode).input_buffer = buf
                     end
+                    return
                 end
             end
             edit_insert(s, ']')
@@ -1337,6 +1335,15 @@ function setup_interface(
     return ModalInterface(allprompts)
 end
 
+function load_pkg()
+    pkgid = Base.PkgId(Base.UUID("44cfe95a-1eb2-52ea-b672-e2afdf69b78f"), "Pkg")
+    if Base.locate_package(pkgid) !== nothing # Only try load Pkg if we can find it
+        Pkg = Base.require(pkgid)
+        return Pkg
+    end
+    return nothing
+end
+
 function run_frontend(repl::LineEditREPL, backend::REPLBackendRef)
     repl.frontend_task = current_task()
     d = REPLDisplay(repl)