When entering into REPL mode while debugging, the backslash tab completions don't work under Julia 1.12. The following example works in 1.10, but is broken in 1.12:
julia> using Debugger
julia> fn() = nothing
julia> @enter fn()
In fn() at REPL[2]:1
>1 fn() = nothing
About to run: return
1|julia> \Omega┌ Error: Error in the keymap
│ exception =
│ MethodError: no method matching _completion_text(::REPL.REPLCompletions.BslashCompletion)
│ The function `_completion_text` exists, but no method is defined for this combination of argument types.
│
│ Closest candidates are:
│ _completion_text(::REPL.REPLCompletions.KeywordCompletion)
│ @ REPL ~/.julia/juliaup/julia-1.12.5+0.x64.linux.gnu/share/julia/stdlib/v1.12/REPL/src/REPLCompletions.jl:115
│ _completion_text(::REPL.REPLCompletions.PathCompletion)
│ @ REPL ~/.julia/juliaup/julia-1.12.5+0.x64.linux.gnu/share/julia/stdlib/v1.12/REPL/src/REPLCompletions.jl:117
│ _completion_text(::REPL.REPLCompletions.KeywordArgumentCompletion)
│ @ REPL ~/.julia/juliaup/julia-1.12.5+0.x64.linux.gnu/share/julia/stdlib/v1.12/REPL/src/REPLCompletions.jl:125
│ ...
│
│ Stacktrace:
│ [1] completion_text(c::REPL.REPLCompletions.BslashCompletion)
│ @ REPL.REPLCompletions ~/.julia/juliaup/julia-1.12.5+0.x64.linux.gnu/share/julia/stdlib/v1.12/REPL/src/REPLCompletions.jl:127
│ [2] iterate
│ @ ./generator.jl:48 [inlined]
│ [3] _collect(c::Vector{REPL.REPLCompletions.Completion}, itr::Base.Generator{Vector{REPL.REPLCompletions.Completion}, typeof(REPL.REPLCompletions.completion_text)}, ::Base.EltypeUnknown, isz::Base.HasShape{1})
│ @ Base ~/.julia/juliaup/julia-1.12.5+0.x64.linux.gnu/share/julia/base/array.jl:810
│ [4] completions(c::Debugger.DebugCompletionProvider, full::String, partial::String)
│ @ Debugger ~/.julia/packages/Debugger/XviAX/src/repl.jl:250
│ [5] complete_line(c::Debugger.DebugCompletionProvider, s::REPL.LineEdit.PromptState; hint::Bool)
│ @ Debugger ~/.julia/packages/Debugger/XviAX/src/repl.jl:246
│ [6] complete_line(c::REPL.LineEdit.CompletionProvider, s::Any, ::Module; hint::Bool)
│ @ REPL.LineEdit ~/.julia/juliaup/julia-1.12.5+0.x64.linux.gnu/share/julia/stdlib/v1.12/REPL/src/LineEdit.jl:202
│ [7] complete_line_named(c::Any, s::Any, args::Any; kwargs...)
│ @ REPL.LineEdit ~/.julia/juliaup/julia-1.12.5+0.x64.linux.gnu/share/julia/stdlib/v1.12/REPL/src/LineEdit.jl:401
│ [8] complete_line_named
│ @ ~/.julia/juliaup/julia-1.12.5+0.x64.linux.gnu/share/julia/stdlib/v1.12/REPL/src/LineEdit.jl:400 [inlined]
│ [9] complete_line(s::REPL.LineEdit.PromptState, repeats::Int64, mod::Module; hint::Bool)
│ @ REPL.LineEdit ~/.julia/juliaup/julia-1.12.5+0.x64.linux.gnu/share/julia/stdlib/v1.12/REPL/src/LineEdit.jl:497
│ [10] complete_line(s::REPL.LineEdit.PromptState, repeats::Int64, mod::Module)
│ @ REPL.LineEdit ~/.julia/juliaup/julia-1.12.5+0.x64.linux.gnu/share/julia/stdlib/v1.12/REPL/src/LineEdit.jl:496
│ [11] complete_line(s::REPL.LineEdit.MIState)
│ @ REPL.LineEdit ~/.julia/juliaup/julia-1.12.5+0.x64.linux.gnu/share/julia/stdlib/v1.12/REPL/src/LineEdit.jl:386
│ [12] edit_tab(s::REPL.LineEdit.MIState, jump_spaces::Bool, delete_trailing::Bool)
│ @ REPL.LineEdit ~/.julia/juliaup/julia-1.12.5+0.x64.linux.gnu/share/julia/stdlib/v1.12/REPL/src/LineEdit.jl:2518
│ [13] edit_tab
│ @ ~/.julia/juliaup/julia-1.12.5+0.x64.linux.gnu/share/julia/stdlib/v1.12/REPL/src/LineEdit.jl:2518 [inlined]
│ [14] (::REPL.LineEdit.var"#141#142")(::REPL.LineEdit.MIState, ::Any, ::Vararg{Any})
│ @ REPL.LineEdit ~/.julia/juliaup/julia-1.12.5+0.x64.linux.gnu/share/julia/stdlib/v1.12/REPL/src/LineEdit.jl:2564
│ [15] (::REPL.LineEdit.var"#match_input##0#match_input##1"{REPL.LineEdit.var"#141#142", String})(s::Any, p::Any)
│ @ REPL.LineEdit ~/.julia/juliaup/julia-1.12.5+0.x64.linux.gnu/share/julia/stdlib/v1.12/REPL/src/LineEdit.jl:1810
│ [16] macro expansion
│ @ ~/.julia/juliaup/julia-1.12.5+0.x64.linux.gnu/share/julia/stdlib/v1.12/REPL/src/LineEdit.jl:2960 [inlined]
│ [17] macro expansion
│ @ ./lock.jl:376 [inlined]
│ [18] (::REPL.LineEdit.var"#prompt!##2#prompt!##3"{Base.Terminals.TTYTerminal, REPL.LineEdit.ModalInterface, REPL.LineEdit.MIState, REPL.LineEdit.Prompt})()
│ @ REPL.LineEdit ~/.julia/juliaup/julia-1.12.5+0.x64.linux.gnu/share/julia/stdlib/v1.12/REPL/src/LineEdit.jl:2949
└ @ REPL.LineEdit ~/.julia/juliaup/julia-1.12.5+0.x64.linux.gnu/share/julia/stdlib/v1.12/REPL/src/LineEdit.jl:2962
When entering into REPL mode while debugging, the backslash tab completions don't work under Julia 1.12. The following example works in 1.10, but is broken in 1.12: