From f98c0a5d5243f87206fef88722a91ee5d6efdb00 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Edouard=20Choini=C3=A8re?=
 <27212526+echoix@users.noreply.github.com>
Date: Wed, 15 Jul 2026 07:11:34 +0200
Subject: [PATCH 1/2] Apply suggested fix to lib/raster3d/tilewrite.c from
 Copilot Autofix

Co-authored-by: Copilot Autofix powered by AI <223894421+github-code-quality[bot]@users.noreply.github.com>
---
 lib/raster3d/tilewrite.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/raster3d/tilewrite.c b/lib/raster3d/tilewrite.c
index 6f2c646c5d0..f348a41659e 100644
--- a/lib/raster3d/tilewrite.c
+++ b/lib/raster3d/tilewrite.c
@@ -132,7 +132,7 @@ int Rast3d_write_tile(RASTER3D_Map *map, int tileIndex, const void *tile,
     int rows, cols, depths, xRedundant, yRedundant, zRedundant, nofNum;
 
     /* valid tileIndex ? */
-    if ((tileIndex > map->nTiles) || (tileIndex < 0))
+    if ((tileIndex >= map->nTiles) || (tileIndex < 0))
         Rast3d_fatal_error("Rast3d_write_tile: tileIndex out of range");
 
     /* already written ? */

From 46933580b8137b7c02594ad6d449ecb1ede295de Mon Sep 17 00:00:00 2001
From: Vaclav Petras <wenzeslaus@gmail.com>
Date: Fri, 17 Jul 2026 13:01:33 -0400
Subject: [PATCH 2/2] lib/raster3d: Add test for Rast3d_write_tile tile index
 bounds check

Add a pytest test covering the tileIndex bounds check in
Rast3d_write_tile: an index equal to nTiles must be rejected as out of
range, and the last valid index must be accepted. The invalid call runs
in a subprocess using the grass.lib.raster3d ctypes bindings because the
rejection is a fatal error which exits the calling process.

The out-of-range test fails without the bounds check change in this
branch and passes with it.

The test was written by Claude Code using the Claude Fable 5 model.
---
 .../tests/lib_raster3d_tilewrite_test.py      | 94 +++++++++++++++++++
 1 file changed, 94 insertions(+)
 create mode 100644 lib/raster3d/tests/lib_raster3d_tilewrite_test.py

diff --git a/lib/raster3d/tests/lib_raster3d_tilewrite_test.py b/lib/raster3d/tests/lib_raster3d_tilewrite_test.py
new file mode 100644
index 00000000000..d8b59bfda4e
--- /dev/null
+++ b/lib/raster3d/tests/lib_raster3d_tilewrite_test.py
@@ -0,0 +1,94 @@
+"""Test tile index bounds checking in Rast3d_write_tile"""
+
+import os
+import subprocess
+import sys
+
+import pytest
+
+import grass.script as gs
+
+WRITE_TILE_SCRIPT = """\
+import sys
+from ctypes import POINTER, byref, c_float, cast
+
+from grass.lib.gis import G_gisinit
+from grass.lib.raster import FCELL_TYPE
+from grass.lib.raster3d import (
+    RASTER3D_NO_CACHE,
+    RASTER3D_Map,
+    RASTER3D_Region,
+    Rast3d_adjust_region,
+    Rast3d_init_defaults,
+    Rast3d_open_cell_new,
+    Rast3d_write_tile,
+)
+
+index_offset = int(sys.argv[1])
+
+G_gisinit("test")
+Rast3d_init_defaults()
+
+region = RASTER3D_Region()
+region.north = 100
+region.south = 0
+region.east = 100
+region.west = 0
+region.top = 100
+region.bottom = 0
+region.rows = 10
+region.cols = 10
+region.depths = 10
+Rast3d_adjust_region(byref(region))
+
+handle = Rast3d_open_cell_new(
+    "bounds_check_3d", FCELL_TYPE, RASTER3D_NO_CACHE, byref(region)
+)
+if not handle:
+    sys.exit("Rast3d_open_cell_new failed")
+map_ptr = cast(handle, POINTER(RASTER3D_Map))
+tile = (c_float * map_ptr.contents.tileSize)()
+Rast3d_write_tile(map_ptr, map_ptr.contents.nTiles + index_offset, tile, FCELL_TYPE)
+print("tile write accepted")
+"""
+
+
+@pytest.fixture
+def session(tmp_path):
+    """Active session in an XY project (scope: function)"""
+    project = tmp_path / "xy_test"
+    gs.create_project(project)
+    with gs.setup.init(project, env=os.environ.copy()) as session:
+        yield session
+
+
+def write_tile(index_offset, session, tmp_path):
+    """Call Rast3d_write_tile with tile index nTiles + index_offset.
+
+    Runs in a subprocess because an invalid index triggers a fatal error
+    which exits the calling process.
+    """
+    script = tmp_path / "write_tile.py"
+    script.write_text(WRITE_TILE_SCRIPT, encoding="utf-8")
+    return subprocess.run(
+        [sys.executable, str(script), str(index_offset)],
+        env=session.env,
+        capture_output=True,
+        text=True,
+        timeout=60,
+        check=False,
+    )
+
+
+def test_write_tile_accepts_last_index(session, tmp_path):
+    """Writing the last valid tile index (nTiles - 1) is accepted"""
+    result = write_tile(-1, session, tmp_path)
+    assert result.returncode == 0, result.stderr
+    assert "tile write accepted" in result.stdout
+
+
+def test_write_tile_rejects_index_past_end(session, tmp_path):
+    """A tile index equal to nTiles is rejected as out of range"""
+    result = write_tile(0, session, tmp_path)
+    assert result.returncode != 0, "out-of-range tile index was accepted"
+    assert "tileIndex out of range" in result.stderr