mention methodtable Ctrl+Q trick in methodshow (#35556)

Co-authored-by: Takafumi Arakaki <[email protected]>
Co-authored-by: Jameson Nash <[email protected]>

base/errorshow.jl

@@ -538,13 +538,10 @@ function show_method_candidates(io::IO, ex::MethodError, @nospecialize kwargs=()
     end
 end
 
-# Contains file name and file number. Gets set when a backtrace
-# or methodlist is shown. Used by the REPL to make it possible to open
-# the location of a stackframe/method in the editor.
-global LAST_SHOWN_LINE_INFOS = Tuple{String, Int}[]
-
 function show_trace_entry(io, frame, n; prefix = "")
-    push!(LAST_SHOWN_LINE_INFOS, (string(frame.file), frame.line))
+    if haskey(io, :LAST_SHOWN_LINE_INFOS)
+        push!(io[:LAST_SHOWN_LINE_INFOS], (string(frame.file), frame.line))
+    end
     print(io, "\n", prefix)
     show(io, frame, full_path=true)
     n > 1 && print(io, " (repeats ", n, " times)")
@@ -631,7 +628,9 @@ function show_reduced_backtrace(io::IO, t::Vector, with_prefix::Bool)
 end
 
 function show_backtrace(io::IO, t::Vector)
-    resize!(LAST_SHOWN_LINE_INFOS, 0)
+    if haskey(io, :LAST_SHOWN_LINE_INFOS)
+        resize!(io[:LAST_SHOWN_LINE_INFOS], 0)
+    end
     filtered = process_backtrace(t)
     isempty(filtered) && return
 

base/methodshow.jl

@@ -240,6 +240,7 @@ function show_method_table(io::IO, ms::MethodList, max::Int=-1, header::Bool=tru
     end
     n = rest = 0
     local last
+    LAST_SHOWN_LINE_INFOS = get(io, :LAST_SHOWN_LINE_INFOS, Tuple{String,Int}[])
 
     resize!(LAST_SHOWN_LINE_INFOS, 0)
     for meth in ms
@@ -373,6 +374,7 @@ show(io::IO, mime::MIME"text/html", mt::Core.MethodTable) = show(io, mime, Metho
 
 # pretty-printing of AbstractVector{Method}
 function show(io::IO, mime::MIME"text/plain", mt::AbstractVector{Method})
+    LAST_SHOWN_LINE_INFOS = get(io, :LAST_SHOWN_LINE_INFOS, Tuple{String,Int}[])
     resize!(LAST_SHOWN_LINE_INFOS, 0)
     first = true
     for (i, m) in enumerate(mt)

stdlib/REPL/src/REPL.jl

@@ -211,8 +211,22 @@ function display(d::REPLDisplay, mime::MIME"text/plain", x)
         io = foldl(IOContext, d.repl.options.iocontext,
                    init=IOContext(io, :limit => true, :module => Main))
     end
+
+    infos = Tuple{String,Int}[]
+    io = IOContext(io, :LAST_SHOWN_LINE_INFOS => infos)
+
     show(io, mime, x)
     println(io)
+
+    if !isempty(infos)
+        d.repl.last_shown_line_infos = infos
+        println(
+            io,
+            "\nTo edit a specific method, type the corresponding number into the " *
+            "REPL and press Ctrl+Q",
+        )
+    end
+
     nothing
 end
 display(d::REPLDisplay, x) = display(d, MIME("text/plain"), x)
@@ -430,11 +444,12 @@ mutable struct LineEditREPL <: AbstractREPL
     specialdisplay::Union{Nothing,AbstractDisplay}
     options::Options
     mistate::Union{MIState,Nothing}
+    last_shown_line_infos::Vector{Tuple{String,Int}}
     interface::ModalInterface
     backendref::REPLBackendRef
     LineEditREPL(t,hascolor,prompt_color,input_color,answer_color,shell_color,help_color,history_file,in_shell,in_help,envcolors) =
         new(t,hascolor,prompt_color,input_color,answer_color,shell_color,help_color,history_file,in_shell,
-            in_help,envcolors,false,nothing, Options(), nothing)
+            in_help,envcolors,false,nothing, Options(), nothing, Tuple{String,Int}[])
 end
 outstream(r::LineEditREPL) = r.t
 specialdisplay(r::LineEditREPL) = r.specialdisplay
@@ -1092,10 +1107,10 @@ function setup_interface(
         end,
 
         # Open the editor at the location of a stackframe or method
-        # This is accessing a global variable that gets set in
+        # This is accessing a contextual variable that gets set in
         # the show_backtrace and show_method_table functions.
         "^Q" => (s, o...) -> begin
-            linfos = Base.LAST_SHOWN_LINE_INFOS
+            linfos = repl.last_shown_line_infos
             str = String(take!(LineEdit.buffer(s)))
             n = tryparse(Int, str)
             n === nothing && @goto writeback