From 980b83d3f8703f3dd0ee03df8a6916364265baef Mon Sep 17 00:00:00 2001
From: Michael Abbott <32575566+mcabbott@users.noreply.github.com>
Date: Thu, 25 Jul 2024 05:48:10 -0400
Subject: [PATCH] Fix a bug in `stack`'s DimensionMismatch error message
 (#54033)

`stack` does not require that the inner iterator defines `axes`, but the
code to assemble an error message assumed this.

Found here:
https://discourse.julialang.org/t/reduce-hcat-is-type-unstable/112800/3

(cherry picked from commit ae483c352273af392e1dd6bd2cb3b044ffa46111)
---
 base/abstractarray.jl | 2 +-
 test/abstractarray.jl | 3 +++
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/base/abstractarray.jl b/base/abstractarray.jl
index 7be13ad34a66d..d7ef5e2b69f2b 100644
--- a/base/abstractarray.jl
+++ b/base/abstractarray.jl
@@ -2891,7 +2891,7 @@ end
 @inline function _stack_size_check(x, ax1::Tuple)
     if _iterator_axes(x) != ax1
         uax1 = map(UnitRange, ax1)
-        uaxN = map(UnitRange, axes(x))
+        uaxN = map(UnitRange, _iterator_axes(x))
         throw(DimensionMismatch(
             LazyString("stack expects uniform slices, got axes(x) == ", uaxN, " while first had ", uax1)))
     end
diff --git a/test/abstractarray.jl b/test/abstractarray.jl
index 9691db88b6e99..8d0c83897611b 100644
--- a/test/abstractarray.jl
+++ b/test/abstractarray.jl
@@ -1684,6 +1684,9 @@ end
     @test_throws ArgumentError stack([1:3, 4:6]; dims=3)
     @test_throws ArgumentError stack(abs2, 1:3; dims=2)
 
+    @test stack(["hello", "world"]) isa Matrix{Char}
+    @test_throws DimensionMismatch stack(["hello", "world!"])  # had a bug in error printing
+
     # Empty
     @test_throws ArgumentError stack(())
     @test_throws ArgumentError stack([])