Add patch for FLINT 3.3.0 bug that caused LU decomposition segfaults

Initialize permutation vector even when there are no columns

[ci skip]

Author: d-torrance

M2/cmake/build-libraries.cmake

@@ -344,6 +344,7 @@ ExternalProject_Add(build-flint
   PREFIX            libraries/flint
   SOURCE_DIR        ${CMAKE_SOURCE_DIR}/submodules/flint
   BUILD_IN_SOURCE   ON
+  PATCH_COMMAND     patch --batch -p1 < ${CMAKE_SOURCE_DIR}/libraries/flint/patch-3.3.0
   CONFIGURE_COMMAND ./bootstrap.sh &&
                     ${CONFIGURE} --prefix=${M2_HOST_PREFIX}
                     ${shared_setting}

M2/libraries/flint/Makefile.in

@@ -3,7 +3,7 @@ SUBMODULE = true
 HOMEPAGE = http://flintlib.org
 # git://github.com/wbhart/flint2.git
 VERSION = 3.3.0
-# PATCHFILE = @abs_srcdir@/patch-$(VERSION)
+PATCHFILE = @abs_srcdir@/patch-$(VERSION)
 PARALLEL = yes
 
 # Many other tests keep failing, so disable them all:

M2/libraries/flint/patch-3.3.0

@@ -0,0 +1,53 @@
+From e36ec985019d8ee3ef21739cc4fc6774f2336cd2 Mon Sep 17 00:00:00 2001
+From: Fredrik Johansson <[email protected]>
+Date: Sat, 14 Jun 2025 20:34:17 +0200
+Subject: [PATCH] gr_mat_lu_classical: set permutation vector even if there are
+ 0 columns
+
+---
+ src/gr_mat/lu_classical.c | 19 ++++++++++---------
+ 1 file changed, 10 insertions(+), 9 deletions(-)
+
+diff --git a/src/gr_mat/lu_classical.c b/src/gr_mat/lu_classical.c
+index 003cfd5d9b..a0043d40dd 100644
+--- a/src/gr_mat/lu_classical.c
++++ flint-3.3.0/src/gr_mat/lu_classical.c
+@@ -34,25 +34,26 @@ gr_mat_lu_classical(slong * res_rank, slong * P, gr_mat_t LU, const gr_mat_t A,
+     int status = GR_SUCCESS;
+     int pivot_status;
+ 
+-    if (gr_mat_is_empty(A, ctx) == T_TRUE)
++    m = gr_mat_nrows(A, ctx);
++    n = gr_mat_ncols(A, ctx);
++
++    rank = row = col = 0;
++    for (i = 0; i < m; i++)
++        P[i] = i;
++
++    if (m == 0 || n == 0)
+     {
+         *res_rank = 0;
+         return GR_SUCCESS;
+     }
+ 
+-    GR_TMP_INIT2(d, e, ctx);
+-
+-    m = gr_mat_nrows(A, ctx);
+-    n = gr_mat_ncols(A, ctx);
+     sz = ctx->sizeof_elem;
+ 
+     status |= gr_mat_set(LU, A, ctx);
+ 
+-#define ENTRY(ii, jj) GR_MAT_ENTRY(LU, ii, jj, sz)
++    GR_TMP_INIT2(d, e, ctx);
+ 
+-    rank = row = col = 0;
+-    for (i = 0; i < m; i++)
+-        P[i] = i;
++#define ENTRY(ii, jj) GR_MAT_ENTRY(LU, ii, jj, sz)
+ 
+     while (row < m && col < n)
+     {
+-- 
+2.43.0
+