From 694f59451388a1faf54dec37f2478875ce1ce572 Mon Sep 17 00:00:00 2001
From: Tommy Hofmann <thofma@gmail.com>
Date: Fri, 15 Dec 2023 20:04:38 +0100
Subject: [PATCH] Add missing ring interface function for AlgClosure (#3113)

---
 src/Rings/AlgClosureFp.jl  | 3 +++
 test/Rings/AlgClosureFp.jl | 4 ++++
 2 files changed, 7 insertions(+)

diff --git a/src/Rings/AlgClosureFp.jl b/src/Rings/AlgClosureFp.jl
index e0099bd9f14a..2e9725e32c0a 100644
--- a/src/Rings/AlgClosureFp.jl
+++ b/src/Rings/AlgClosureFp.jl
@@ -44,6 +44,8 @@ end
 elem_type(::Type{AlgClosure{T}}) where T = AlgClosureElem{T}
 parent_type(::Type{AlgClosureElem{T}}) where T = AlgClosure{T}
 
+Oscar.canonical_unit(a::AlgClosureElem) = is_zero(a) ? one(a) : a
+
 function show(io::IO, a::AlgClosureElem)
   print(io, data(a))
 end
@@ -325,6 +327,7 @@ function has_preimage(mp::MapFromFunc{T, AlgClosure{S}}, elm::AlgClosureElem{S})
   return true, preimage(mp, elm)
 end
 
+
 end # AlgClosureFp
 
 import .AlgClosureFp:
diff --git a/test/Rings/AlgClosureFp.jl b/test/Rings/AlgClosureFp.jl
index 1b64f8d27fc1..056addfef31c 100644
--- a/test/Rings/AlgClosureFp.jl
+++ b/test/Rings/AlgClosureFp.jl
@@ -177,4 +177,8 @@ end
     a = K(gen(F1))
     @test K(L(a)) == a
   end
+
+  R = algebraic_closure(GF(3,1))
+  Kt, t = rational_function_field(R, "t")
+  @test sprint(show, t) isa String
 end