From 9f67d865a8869b9d0ec7deb73e11e5bad1e43700 Mon Sep 17 00:00:00 2001
From: Johannes Schmitt <jschmitt@posteo.eu>
Date: Tue, 15 Aug 2023 15:26:05 +0200
Subject: [PATCH] Make `divexact(::fmpq_poly, ::fmpq_poly)` honour the `check`
 keyword

---
 src/flint/fmpq_poly.jl       | 10 +++++++++-
 test/flint/fmpq_poly-test.jl |  4 ++++
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/src/flint/fmpq_poly.jl b/src/flint/fmpq_poly.jl
index 4ed63eb51..c7e07b358 100644
--- a/src/flint/fmpq_poly.jl
+++ b/src/flint/fmpq_poly.jl
@@ -446,7 +446,15 @@ function Base.div(x::QQPolyRingElem, y::QQPolyRingElem)
    return z
 end
 
-divexact(x::QQPolyRingElem, y::QQPolyRingElem; check::Bool=true) = div(x,y)
+function divexact(x::QQPolyRingElem, y::QQPolyRingElem; check::Bool=true)
+   if !check
+      return div(x, y)
+   else
+      q, r = divrem(x, y)
+      !iszero(r) && throw(ArgumentError("not an exact division"))
+      return q
+   end
+end
 
 ###############################################################################
 #
diff --git a/test/flint/fmpq_poly-test.jl b/test/flint/fmpq_poly-test.jl
index 514686655..fe847b1ef 100644
--- a/test/flint/fmpq_poly-test.jl
+++ b/test/flint/fmpq_poly-test.jl
@@ -361,6 +361,10 @@ end
 
    f = 3*y^2 + 7*y + 3
 
+   @test divexact(f, f) == one(S)
+
+   @test_throws ArgumentError divexact(f, y)
+
    @test divexact(3*f, 3) == f
 
    @test divexact(ZZRingElem(3)*f, ZZRingElem(3)) == f