`Meta.parse` changed trailing newline behavior with julia 1.12

[lgoettgens]

Consider the following example:

   _       _ _(_)_     |  Documentation: https://docs.julialang.org
  (_)     | (_) (_)    |
   _ _   _| |_  __ _   |  Type "?" for help, "]?" for Pkg help.
  | | | | | | |/ _` |  |
  | | |_| | | | (_| |  |  Version 1.11.7 (2025-09-08)
 _/ |\__'_|_|_|\__'_|  |  Official https://julialang.org/ release
|__/                   |

julia> Meta.parse("x=1\n\n")
:(x = 1)

   _       _ _(_)_     |  Documentation: https://docs.julialang.org
  (_)     | (_) (_)    |
   _ _   _| |_  __ _   |  Type "?" for help, "]?" for Pkg help.
  | | | | | | |/ _` |  |
  | | |_| | | | (_| |  |  Version 1.12.1 (2025-10-17)
 _/ |\__'_|_|_|\__'_|  |  Official https://julialang.org release
|__/                   |

julia> Meta.parse("\n\n")

julia> Meta.parse("x=1\n\n")
ERROR: ParseError("extra token after end of expression")
Stacktrace:
 [1] parse(str::String; filename::String, raise::Bool, depwarn::Bool)
   @ Base.Meta ./meta.jl:283
 [2] parse(str::String)
   @ Base.Meta ./meta.jl:276
 [3] top-level scope
   @ REPL[1]:1

In julia 1.11.x and earlier, this parsed just fine, but starting with julia 1.12 (and also on a current nightly) this throws a ParseError.

This came up yesterday in the regression CI of Documenter.jl in JuliaDocs/Documenter.jl#2777.

cc @fingolfin

[fingolfin]

According to git bisect this is due to commit 3e08cb1 / PR #57188, i.e., the merging of JuliaSyntax 1.0.0 (admittedly not very surprising ;-).

So perhaps also submit this to https://github.com/JuliaLang/JuliaSyntax.jl/issues?

[vtjnash]

I should note this has been reported a number of times, most recently in #59940 (follow links from there also)

[fingolfin]

Aha, so indeed Meta.parse("x=1\n\n") raised the same error in Julia 1.6 - 1.9; it only "worked" in Julia 1.10 and 1.11. So in this way the "new" behavior is a bug fix.

But I think there must be more going on -- I am pretty sure the OSCAR tests in question not so long ago also worked in Julia 1.6 - 1.9 -- am I wrong, @lgoettgens ?

[lgoettgens]

But I think there must be more going on -- I am pretty sure the OSCAR tests in question not so long ago also worked in Julia 1.6 - 1.9 -- am I wrong, @lgoettgens ?

The issue did not occurr during testing but just during building the docs. And that only ran on julia 1.10 for quite some time