From 016cc0a2caceea46a140359568b223f6ec37aaeb Mon Sep 17 00:00:00 2001
From: Max Horn <max@quendi.de>
Date: Thu, 15 Oct 2026 13:09:11 +0200
Subject: [PATCH] Accept new plist matrix view format in tests

GAP 4.17 views matrices in IsPlistMatrixRep as
<2x2 plist matrix over R> instead of <2x2-matrix over R>
(gap-system/gap#6686), which broke the standard tests and four
manual examples.

Update the expected outputs to the new format and normalise the old
one via a transformFunction in SEMIGROUPS.TestRec and in the manual
example runner, so the tests pass with both old and new GAP. The
transform can be removed once GAP < 4.17 is no longer supported.

Assisted-by: Claude Code (Opus 5.5)
---
 doc/maxplusmat.xml                    |  8 ++++----
 doc/semiringmat.xml                   |  8 ++++----
 gap/tools/utils.gi                    |  7 +++++++
 tst/standard/elements/ffmat.tst       |  2 +-
 tst/standard/elements/maxplusmat.tst  | 18 +++++++++---------
 tst/standard/elements/semiringmat.tst | 10 +++++-----
 tst/standard/greens/generic.tst       |  2 +-
 7 files changed, 31 insertions(+), 24 deletions(-)

diff --git a/doc/maxplusmat.xml b/doc/maxplusmat.xml
index f0e7d18d6..81c1eb37a 100644
--- a/doc/maxplusmat.xml
+++ b/doc/maxplusmat.xml
@@ -191,9 +191,9 @@ gap> PeriodNTPMatrix(mat);
 gap> mat := Matrix(Integers, [[0, 0, -1],
 >                             [0, 1, 0],
 >                             [1, 0, 0]]);
-<3x3-matrix over Integers>
+<3x3 plist matrix over Integers>
 gap> InverseOp(mat);
-<3x3-matrix over Integers>
+<3x3 plist matrix over Integers>
 gap> mat * InverseOp(mat) = One(mat);
 true
 ]]></Example>
@@ -219,14 +219,14 @@ true
 gap> mat := Matrix(Integers, [[0, 0, -1],
 >                             [0, 1, 0],
 >                             [1, 0, 0]]);
-<3x3-matrix over Integers>
+<3x3 plist matrix over Integers>
 gap> IsTorsion(mat);
 true
 gap> mat := Matrix(Integers, [[0, 0, -1, 0],
 >                             [0, -1, 0, 0],
 >                             [4, 4, 2, -1],
 >                             [1, 1, 0, 3]]);
-<4x4-matrix over Integers>
+<4x4 plist matrix over Integers>
 gap> IsTorsion(mat);
 false
 ]]></Example>
diff --git a/doc/semiringmat.xml b/doc/semiringmat.xml
index a74cde721..b7812b338 100644
--- a/doc/semiringmat.xml
+++ b/doc/semiringmat.xml
@@ -90,7 +90,7 @@ gap> mat := Matrix(IsNTPMatrix, [[1, 2, 2],
 >                                [0, 2, 0],
 >                                [1, 3, 0]], 4, 5);;
 gap> Matrix(Integers, mat);
-<3x3-matrix over Integers>
+<3x3 plist matrix over Integers>
 gap> mat := Matrix(IsMinPlusMatrix, [[0, 1, 3], [1, 1, 6], [0, 4, 2]]);;
 gap> mat := AsMatrix(IsTropicalMinPlusMatrix, mat, 2);
 Matrix(IsTropicalMinPlusMatrix, [[0, 1, 2], [1, 1, 2], [0, 2, 2]], 2)
@@ -118,7 +118,7 @@ Matrix(IsNTPMatrix, [[0, 1, 0], [1, 3, 1], [1, 0, 1]], 2, 6)
 gap> mat := AsMatrix(IsNTPMatrix, mat, 2, 1);
 Matrix(IsNTPMatrix, [[0, 1, 0], [1, 2, 1], [1, 0, 1]], 2, 1)
 gap> mat := Matrix(Integers, mat);
-<3x3-matrix over Integers>
+<3x3 plist matrix over Integers>
 gap> AsMatrix(IsNTPMatrix, mat, 1, 2);
 Matrix(IsNTPMatrix, [[0, 1, 0], [1, 2, 1], [1, 0, 1]], 1, 2)]]></Example>
     </Description>
@@ -351,11 +351,11 @@ Matrix(IsNTPMatrix, [[0, 0, 0], [2, 0, 1], [2, 2, 2]], 2, 1)
 gap> Matrix(Integers, [[-1, -2, 0],
 >                      [0, 3, -1],
 >                      [1, 0, -3]]);
-<3x3-matrix over Integers>
+<3x3 plist matrix over Integers>
 gap> Matrix(Integers, [[-1, -2, 0],
 >                      [0, 3, -1],
 >                      [1, 0, -3]]);
-<3x3-matrix over Integers>
+<3x3 plist matrix over Integers>
 ]]></Example>
 <!-- Another test, for a matrix over a finite field
 gap> Matrix(GF(3), [[Z(3), Z(3) ^ 0, Z(3)],
diff --git a/gap/tools/utils.gi b/gap/tools/utils.gi
index e7dd0d58d..5708ebfc9 100644
--- a/gap/tools/utils.gi
+++ b/gap/tools/utils.gi
@@ -54,6 +54,11 @@ SEMIGROUPS.TestRec.reportDiff := function(inp, expout, found, fnam, line, _)
   return;
 end;
 
+# GAP 4.17 views plist matrices as <2x2 plist matrix over R>, earlier versions
+# as <2x2-matrix over R>.
+SEMIGROUPS.TestRec.transformFunction :=
+  str -> ReplacedString(str, "-matrix over ", " plist matrix over ");
+
 SEMIGROUPS.StartTest := function()
   local record;
 
@@ -335,6 +340,8 @@ SEMIGROUPS.RunExamples := function(exlists, nums, excluded)
 
         start_time := IO_gettimeofday();
         test := Test(s, rec(compareFunction := "uptowhitespace",
+                            transformFunction :=
+                              SEMIGROUPS.TestRec.transformFunction,
                             ignoreComments := false,
                             width := 72,
                             EQ := \=,
diff --git a/tst/standard/elements/ffmat.tst b/tst/standard/elements/ffmat.tst
index 7a205eafe..aacb5b62a 100644
--- a/tst/standard/elements/ffmat.tst
+++ b/tst/standard/elements/ffmat.tst
@@ -285,7 +285,7 @@ Z(2^2)^2
 
 # Finite field matrix attributes TryNextMethod
 gap> x := Matrix(Integers, [[-1, -2, 0], [0, 3, -1], [1, 0, -3]]);
-<3x3-matrix over Integers>
+<3x3 plist matrix over Integers>
 gap> RowSpaceBasis(x);
 Error, no method found! For debugging hints type ?Recovery from NoMethodFound
 Error, no 2nd choice method found for `RowSpaceBasis' on 1 arguments
diff --git a/tst/standard/elements/maxplusmat.tst b/tst/standard/elements/maxplusmat.tst
index 68f9d68f8..61dc3154e 100644
--- a/tst/standard/elements/maxplusmat.tst
+++ b/tst/standard/elements/maxplusmat.tst
@@ -205,15 +205,15 @@ Error, the 3rd argument (a pos. int.) is not > 0
 gap> mat := Matrix(Integers, [[-1, -2, 0],
 >                             [0, 3, -1],
 >                             [1, 0, -3]]);
-<3x3-matrix over Integers>
+<3x3 plist matrix over Integers>
 gap> mat2 := Matrix(Integers, [[-1, -2, 0],
 >                      [0, 3, -1],
 >                      [1, 0, -3]]);
-<3x3-matrix over Integers>
+<3x3 plist matrix over Integers>
 gap> mat2 * mat;
-<3x3-matrix over Integers>
+<3x3 plist matrix over Integers>
 gap> One(mat);
-<immutable 3x3-matrix over Integers>
+<immutable 3x3 plist matrix over Integers>
 gap> One(mat) * mat = mat;
 true
 gap> mat * One(mat) = mat;
@@ -225,7 +225,7 @@ gap> mat3 := Matrix(Integers, [[2, 2, 0, 1, 0], [2, 3, 0, 1, -2],
 gap> mat * mat3;
 Error, \*: Matrices do not fit together
 gap> RandomMatrix(Integers, 20);
-<20x20-matrix over Integers>
+<20x20 plist matrix over Integers>
 
 # maxplusmat: AsMatrix, trop. min-plus <-> min-plus, 1/3
 gap> mat := Matrix(IsTropicalMinPlusMatrix, [[1, infinity, 1], [0, infinity, 2],
@@ -272,7 +272,7 @@ gap> mat := Matrix(IsNTPMatrix, [[1, 2, 2],
 >                                [0, 2, 0],
 >                                [1, 3, 0]], 4, 5);;
 gap> Matrix(Integers, mat);
-<3x3-matrix over Integers>
+<3x3 plist matrix over Integers>
 gap> mat := Matrix(IsMinPlusMatrix, [[0, 1, 3], [1, 1, 6], [0, 4, 2]]);;
 gap> mat := AsMatrix(IsTropicalMinPlusMatrix, mat, 2);
 Matrix(IsTropicalMinPlusMatrix, [[0, 1, 2], [1, 1, 2], [0, 2, 2]], 2)
@@ -310,7 +310,7 @@ Matrix(IsNTPMatrix, [[0, 1, 0], [1, 3, 1], [1, 0, 1]], 2, 6)
 gap> mat := AsMatrix(IsNTPMatrix, mat, 2, 1);
 Matrix(IsNTPMatrix, [[0, 1, 0], [1, 2, 1], [1, 0, 1]], 2, 1)
 gap> mat := Matrix(Integers, mat);
-<3x3-matrix over Integers>
+<3x3 plist matrix over Integers>
 gap> AsMatrix(IsNTPMatrix, mat, 1, 2);
 Matrix(IsNTPMatrix, [[0, 1, 0], [1, 2, 1], [1, 0, 1]], 1, 2)
 
@@ -341,7 +341,7 @@ true
 # maxplusmat: InverseOp, for integer matrices
 gap> mat := Matrix(Integers, [[0, 0, -1], [0, 1, 0], [1, 0, 0]]);;
 gap> InverseOp(mat);
-<3x3-matrix over Integers>
+<3x3 plist matrix over Integers>
 gap> mat * InverseOp(mat) = One(mat);
 true
 gap> InverseOp(mat) * mat = One(mat);
@@ -588,7 +588,7 @@ gap> AsMatrix(IsNTPMatrix, IdentityTransformation, 3, 3);
 Error, no method found! For debugging hints type ?Recovery from NoMethodFound
 Error, no 1st choice method found for `AsMatrix' on 5 arguments
 gap> Matrix(Integers, Transformation([2, 1, 1]));
-<3x3-matrix over Integers>
+<3x3 plist matrix over Integers>
 gap> Matrix(Integers, IdentityTransformation);
 Error, no method found! For debugging hints type ?Recovery from NoMethodFound
 Error, no 1st choice method found for `Matrix' on 3 arguments
diff --git a/tst/standard/elements/semiringmat.tst b/tst/standard/elements/semiringmat.tst
index 67d25dd0c..30a745033 100644
--- a/tst/standard/elements/semiringmat.tst
+++ b/tst/standard/elements/semiringmat.tst
@@ -66,13 +66,13 @@ true
 gap> Matrix(Integers, [[-1, -2, 0],
 >                      [0, 3, -1],
 >                      [1, 0, -3]]);
-<3x3-matrix over Integers>
+<3x3 plist matrix over Integers>
 gap> TransposedMat(TransposedMat(last)) = last;
 true
 gap> Matrix(Integers, [[-1, -2, 0],
 >                      [0, 3, -1],
 >                      [1, 0, -3]]);
-<3x3-matrix over Integers>
+<3x3 plist matrix over Integers>
 gap> TransposedMat(TransposedMat(last)) = last;
 true
 
@@ -152,7 +152,7 @@ Error, no 2nd choice method found for `Matrix' on 2 arguments
 
 # semiringmat: Matrix, for a semiring and homogeneous list, 2/3
 gap> Matrix(Rationals, [[1, 1], [2, 2]]);
-<2x2-matrix over Rationals>
+<2x2 plist matrix over Rationals>
 
 # semiringmat: Matrix, for a semiring and homogeneous list, 3/3
 # TODO(MatrixObj-later) the following works fine in MatrixObj land
@@ -371,7 +371,7 @@ gap> mat := Matrix(IsNTPMatrix, [[1, 2, 2],
 >                                [0, 2, 0],
 >                                [1, 3, 0]], 4, 5);;
 gap> Matrix(Integers, mat);
-<3x3-matrix over Integers>
+<3x3 plist matrix over Integers>
 gap> mat := Matrix(IsMinPlusMatrix, [[0, 1, 3], [1, 1, 6], [0, 4, 2]]);;
 gap> mat := AsMatrix(IsTropicalMinPlusMatrix, mat, 2);
 Matrix(IsTropicalMinPlusMatrix, [[0, 1, 2], [1, 1, 2], [0, 2, 2]], 2)
@@ -409,7 +409,7 @@ Matrix(IsNTPMatrix, [[0, 1, 0], [1, 3, 1], [1, 0, 1]], 2, 6)
 gap> mat := AsMatrix(IsNTPMatrix, mat, 2, 1);
 Matrix(IsNTPMatrix, [[0, 1, 0], [1, 2, 1], [1, 0, 1]], 2, 1)
 gap> mat := Matrix(Integers, mat);
-<3x3-matrix over Integers>
+<3x3 plist matrix over Integers>
 gap> AsMatrix(IsNTPMatrix, mat, 1, 2);
 Matrix(IsNTPMatrix, [[0, 1, 0], [1, 2, 1], [1, 0, 1]], 1, 2)
 
diff --git a/tst/standard/greens/generic.tst b/tst/standard/greens/generic.tst
index 727da5886..d50c4dcad 100644
--- a/tst/standard/greens/generic.tst
+++ b/tst/standard/greens/generic.tst
@@ -1295,7 +1295,7 @@ gap> Representative(H) ^ x;
 ()
 gap> y := InverseGeneralMapping(x);;
 gap> () ^ y;
-<immutable 8x8-matrix over Integers>
+<immutable 8x8 plist matrix over Integers>
 gap> () ^ y = Representative(H);
 true
 gap> Matrix(Integers, [[0, 0, -1, -1, 3, 3, 1, -1],