Switch to Pkg mode prompt immediately and load Pkg in the background

stdlib/REPL/src/REPL.jl

@@ -1080,9 +1080,6 @@ setup_interface(
  extra_repl_keymap::Any = repl.options.extra_keymap
 ) = setup_interface(repl, hascolor, extra_repl_keymap)
 
-# we have to grab this after Pkg is loaded so cache it
-pkg_mode::Union{Nothing,LineEdit.Prompt} = nothing
-
 # This non keyword method can be precompiled which is important
 function setup_interface(
  repl::LineEditREPL,
@@ -1228,11 +1225,17 @@ function setup_interface(
  end,
  ']' => function (s::MIState,o...)
  if isempty(s) || position(LineEdit.buffer(s)) == 0
- global pkg_mode
- if pkg_mode === nothing
+ # print a dummy pkg prompt while Pkg loads
+ LineEdit.clear_line(LineEdit.terminal(s))
+ # use 6 .'s here because its the same width as the most likely `@v1.xx` env name
+ print(LineEdit.terminal(s), styled"{blue,bold:({gray:......}) pkg> }")
+ pkg_mode = nothing
+ transition_finished = false
+ iolock = Base.ReentrantLock() # to avoid race between tasks reading stdin & input buffer
+ # spawn Pkg load to avoid blocking typing during loading. Typing will block if only 1 thread
+ t_replswitch = Threads.@spawn begin
  pkgid = Base.PkgId(Base.UUID("44cfe95a-1eb2-52ea-b672-e2afdf69b78f"), "Pkg")
  REPLExt = Base.require_stdlib(pkgid, "REPLExt")
- pkg_mode = nothing
  if REPLExt isa Module && isdefined(REPLExt, :PkgCompletionProvider)
  for mode in repl.interface.modes
  if mode isa LineEdit.Prompt && mode.complete isa REPLExt.PkgCompletionProvider
@@ -1241,16 +1244,31 @@ function setup_interface(
  end
  end
  end
+ if pkg_mode !== nothing
+ @lock iolock begin
+ buf = copy(LineEdit.buffer(s))
+ transition(s, pkg_mode) do
+ LineEdit.state(s, pkg_mode).input_buffer = buf
+ end
+ if !isempty(s)
+ @invokelatest(LineEdit.check_for_hint(s)) && @invokelatest(LineEdit.refresh_line(s))
+ end
+ transition_finished = true
+ end
+ end
  end
- if pkg_mode !== nothing
- buf = copy(LineEdit.buffer(s))
- transition(s, pkg_mode) do
- LineEdit.state(s, pkg_mode).input_buffer = buf
+ Base.errormonitor(t_replswitch)
+ # while loading just accept all keys, no keymap functionality
+ while !istaskdone(t_replswitch)
+ # wait but only take if task is still running
+ peek(stdin, Char)
+ @lock iolock begin
+ transition_finished || edit_insert(s, read(stdin, Char))
  end
- return
  end
+ else
+ edit_insert(s, ']')
  end
- edit_insert(s, ']')
  end,
 
  # Bracketed Paste Mode

stdlib/REPL/src/precompile.jl

@@ -220,4 +220,14 @@ end
 generate_precompile_statements()
 
 precompile(Tuple{typeof(getproperty), REPL.REPLBackend, Symbol})
+
+# Helps Pkg repl mode switch
+precompile(Tuple{typeof(REPL.Terminals.clear_line), REPL.Terminals.TTYTerminal})
+precompile(Tuple{typeof(Base.print), REPL.Terminals.TTYTerminal, Base.AnnotatedString{String}})
+precompile(Tuple{typeof(Base.peek), Base.TTY, Type{Char}})
+precompile(Tuple{typeof(Base.similar), Array{String, 1}})
+precompile(Tuple{typeof(Base.Iterators.enumerate), Array{String, 1}})
+precompile(Tuple{typeof(Base.setindex!), Array{String, 1}, String, Int64})
+precompile(Tuple{typeof(Base.convert), Type{Base.Dict{String, Union{Array{String, 1}, String}}}, Base.Dict{String, Any}})
+
 end # Precompile