Require all tuples in eachindex to have the same length. (#48125)

Potential fix for #47898

---------

Co-authored-by: navdeep rana <navdeepr@tifrh.res.in>
Co-authored-by: Oscar Smith <oscardssmith@gmail.com>
Co-authored-by: Jerry Ling <proton@jling.dev>
Co-authored-by: Andy Dienes <51664769+adienes@users.noreply.github.com>

Author: 5 people

base/tuple.jl

@@ -149,12 +149,9 @@ nextind(@nospecialize(t::Tuple), i::Integer) = Int(i)+1
 
 function keys(t::Tuple, t2::Tuple...)
     @inline
-    OneTo(_maxlength(t, t2...))
-end
-_maxlength(t::Tuple) = length(t)
-function _maxlength(t::Tuple, t2::Tuple, t3::Tuple...)
-    @inline
-    max(length(t), _maxlength(t2, t3...))
+    lent = length(t)
+    all(x->length(x) == lent, t2) || throw_eachindex_mismatch_indices(IndexLinear(), t, t2...)
+    Base.OneTo(lent)
 end
 
 # this allows partial evaluation of bounded sequences of next() calls on tuples,

test/tuple.jl

@@ -208,7 +208,7 @@ end
     @test iterate(t, y3[2]) === nothing
 
     @test eachindex((2,5,"foo")) === Base.OneTo(3)
-    @test eachindex((2,5,"foo"), (1,2,5,7)) === Base.OneTo(4)
+    @test_throws DimensionMismatch eachindex((2,5,"foo"), (1,2,5,7))
 
     @test Core.Compiler.is_nothrow(Base.infer_effects(iterate, (Tuple{Int,Int,Int}, Int)))
 end