Pasting "]" into the Julia REPL is inconsistent across platforms

[1-Bart-1]

Pasting ] into the Julia REPL on Ubuntu and MacOS doesn't make the user go into the pkg> REPL mode, while it does work on Windows. See this discussion.

Windows (works):

julia> versioninfo()
Julia Version 1.11.4
Commit 8561cc3d68 (2025-03-10 11:36 UTC)
Build Info:
  Official https://julialang.org/ release
Platform Info:
  OS: Windows (x86_64-w64-mingw32)
  CPU: 8 × Intel(R) Core(TM) i7-1065G7 CPU @ 1.30GHz
  WORD_SIZE: 64
  LLVM: libLLVM-16.0.6 (ORCJIT, icelake-client)
Threads: 1 default, 0 interactive, 1 GC (on 8 virtual cores)

(@v1.11) pkg> # pasted ] before comment

Ubuntu (doesn't work):

bart@BartsPC ~ % lsb_release -a
Distributor ID: Ubuntu
Description:    Ubuntu 24.04.2 LTS
Release:        24.04
Codename:       noble
bart@BartsPC ~ % julia
julia> versioninfo()
Julia Version 1.11.4
Commit 8561cc3d68d (2025-03-10 11:36 UTC)
Build Info:
  Official https://julialang.org/ release
Platform Info:
  OS: Linux (x86_64-linux-gnu)
  CPU: 16 × Intel(R) Core(TM) i9-9980HK CPU @ 2.40GHz
  WORD_SIZE: 64
  LLVM: libLLVM-16.0.6 (ORCJIT, skylake)
Threads: 1 default, 0 interactive, 1 GC (on 16 virtual cores)
Environment:
  LD_LIBRARY_PATH = /usr/local/cuda-12.2/lib64

julia> ] # pasted
ERROR: ParseError:
# Error @ REPL[2]:1:1
] # pasted
╙ ── unexpected `]`
Stacktrace:
 [1] top-level scope
   @ none:1

macOS (doesn't work):

julia> versioninfo()
Julia Version 1.11.4
Commit 8561cc3d68d (2025-03-10 11:36 UTC)
Build Info:
  Official https://julialang.org/ release
Platform Info:
  OS: macOS (arm64-apple-darwin24.0.0)
  CPU: 8 × Apple M1 Pro
  WORD_SIZE: 64
  LLVM: libLLVM-16.0.6 (ORCJIT, apple-m1)
Threads: 1 default, 0 interactive, 1 GC (on 6 virtual cores)
Environment:
  JULIA_EDITOR = lvim

[Keno]

On most platforms, we can detect paste and treat it special. In particular, this makes pasting pkg> work and switch the repl automatically. It also allows us to do things like treat \t as indentation rather than tab completion, etc. In other words, the "broken" behavior is intended. If you want to paste pkg mode, just paste the whole pkg> thing. However, this detection is broken in some windows versions, which is a known issue.

[mbauman]

Ref #53763; the feature is ironically called bracketed paste.