Make TerminalMenus header dynamic. (JuliaLang#38489)

stdlib/REPL/src/TerminalMenus/AbstractMenu.jl

@@ -176,8 +176,6 @@ function request(term::REPL.Terminals.TTYTerminal, m::AbstractMenu; cursor::Unio
  if cursor isa Int
  cursor = Ref(cursor)
  end
- menu_header = header(m)
- !suppress_output && !isempty(menu_header) && println(term.out_stream, menu_header)
 
  state = nothing
  if !suppress_output
@@ -327,6 +325,12 @@ function printmenu(out::IO, m::AbstractMenu, cursoridx::Int; oldstate=nothing, i
  print(buf, "\x1b[999D\x1b[$(ncleared)A") # move left 999 spaces and up `ncleared` lines
  end
 
+ nheaderlines = 0
+ for headerline in split(header(m), "\n", keepempty=false)
+ print(buf, "\x1b[2K", headerline, "\r\n")
+ nheaderlines += 1
+ end
+
  firstline = m.pageoffset+1
  lastline = min(m.pagesize+m.pageoffset, lastoption)
 
@@ -353,7 +357,8 @@ function printmenu(out::IO, m::AbstractMenu, cursoridx::Int; oldstate=nothing, i
  (firstline == lastline || i != lastline) && print(buf, "\r\n")
  end
 
- newstate = lastline-firstline # final line doesn't have `\n`
+ newstate = nheaderlines + lastline - firstline # final line doesn't have `\n`
+
  if newstate < ncleared && oldstate !== nothing
  # we printed fewer lines than last time. Erase the leftovers.
  for i = newstate+1:ncleared

stdlib/REPL/test/TerminalMenus/multiselect_menu.jl

@@ -30,10 +30,10 @@ for kws in ((charset=:ascii,),
  TerminalMenus.writeline(buf, multi_menu, 1, true)
  @test String(take!(buf)) == "$uck 1"
  TerminalMenus.printmenu(buf, multi_menu, 1; init=true)
- @test startswith(String(take!(buf)), string("\e[2K $cur $uck 1"))
+ @test startswith(String(take!(buf)), string("\e[2K[press: d=done, a=all, n=none]\r\n\e[2K $cur $uck 1"))
  push!(multi_menu.selected, 1)
  TerminalMenus.printmenu(buf, multi_menu, 2; init=true)
- @test startswith(String(take!(buf)), string("\e[2K $chk 1\r\n\e[2K $cur $uck 2"))
+ @test startswith(String(take!(buf)), string("\e[2K[press: d=done, a=all, n=none]\r\n\e[2K $chk 1\r\n\e[2K $cur $uck 2"))
 end
 
 # Preselection

stdlib/REPL/test/TerminalMenus/multiselect_with_skip_menu.jl

@@ -30,7 +30,7 @@ function MultiSelectWithSkipMenu(options::Array{String,1}; pagesize::Int=10,
  TerminalMenus.MultiSelectConfig(; kwargs...))
 end
 
-TerminalMenus.header(m::MultiSelectWithSkipMenu) = "[press: d=done, a=all, c=none, npNP=move with skip]"
+TerminalMenus.header(m::MultiSelectWithSkipMenu) = "[press: d=done, a=all, c=none, npNP=move with skip, $(length(m.selected)) items selected]"
 
 TerminalMenus.options(m::MultiSelectWithSkipMenu) = m.options
 
@@ -118,7 +118,13 @@ end
 # These tests are specifically designed to verify that a `RefValue`
 # input to the AbstractMenu `request` function works as intended.
 menu = MultiSelectWithSkipMenu(string.(1:5), selected=[2, 3])
+buf = IOBuffer()
+TerminalMenus.printmenu(buf, menu, 1; init=true)
+@test occursin("2 items selected", String(take!(buf)))
 @test simulate_input(Set([2, 3, 4]), menu, 'n', :enter, 'd')
+buf = IOBuffer()
+TerminalMenus.printmenu(buf, menu, 1; init=true)
+@test occursin("3 items selected", String(take!(buf)))
 
 menu = MultiSelectWithSkipMenu(string.(1:5), selected=[2, 3])
 @test simulate_input(Set([2]), menu, 'P', :enter, 'd', cursor=5)