From 68a21c5a5952913d6192be747efd245887bc36cc Mon Sep 17 00:00:00 2001
From: Alexis Placet <2400067+Alex-PLACET@users.noreply.github.com>
Date: Thu, 30 Apr 2026 13:24:54 +0200
Subject: [PATCH 01/13] Fix substring calculation in CSV cell parsing and add
 lexical_cast for signed and unsigned char

---
 include/xtensor/io/xcsv.hpp | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/include/xtensor/io/xcsv.hpp b/include/xtensor/io/xcsv.hpp
index 080ccaf54..2fd347745 100644
--- a/include/xtensor/io/xcsv.hpp
+++ b/include/xtensor/io/xcsv.hpp
@@ -66,7 +66,7 @@ namespace xt
             }
 
             size_t last = cell.find_last_not_of(' ');
-            return cell.substr(first, last == std::string::npos ? cell.size() : last + 1);
+            return cell.substr(first, last == std::string::npos ? cell.size() : last - first + 1);
         }
 
         template <>
@@ -93,6 +93,18 @@ namespace xt
             return std::stoi(cell);
         }
 
+        template <>
+        inline signed char lexical_cast<signed char>(const std::string& cell)
+        {
+            return static_cast<signed char>(std::stoi(cell));
+        }
+
+        template <>
+        inline unsigned char lexical_cast<unsigned char>(const std::string& cell)
+        {
+            return static_cast<unsigned char>(std::stoul(cell));
+        }
+
         template <>
         inline long lexical_cast<long>(const std::string& cell)
         {

From 005b0c6d1dd1f897ae47b1393b1c07f327b066e6 Mon Sep 17 00:00:00 2001
From: Alexis Placet <2400067+Alex-PLACET@users.noreply.github.com>
Date: Wed, 6 May 2026 16:05:50 +0200
Subject: [PATCH 02/13] Add ASAN CI build

---
 .github/workflows/sanitizers.yml | 98 ++++++++++++++++++++++++++++++++
 cmake/sanitizers.cmake           | 44 ++++++++++++++
 test/CMakeLists.txt              |  3 +
 3 files changed, 145 insertions(+)
 create mode 100644 .github/workflows/sanitizers.yml
 create mode 100644 cmake/sanitizers.cmake

diff --git a/.github/workflows/sanitizers.yml b/.github/workflows/sanitizers.yml
new file mode 100644
index 000000000..4ec16358b
--- /dev/null
+++ b/.github/workflows/sanitizers.yml
@@ -0,0 +1,98 @@
+name: Sanitizers
+on:
+  workflow_dispatch:
+  pull_request:
+  push:
+    branches: [master]
+concurrency:
+  group: ${{ github.workflow }}-${{ github.job }}-${{ github.ref }}
+  cancel-in-progress: true
+defaults:
+  run:
+    shell: bash -e -l {0}
+jobs:
+  build:
+    runs-on: ${{ matrix.os }}
+    name: sanitizer / ${{ matrix.sys.compiler }} ${{ matrix.sys.version }} / ${{ matrix.config.name }} / ${{ matrix.sys.name }}
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [ubuntu-24.04]
+        sys:
+        - {compiler: clang, version: '19', name: asan}
+        - {compiler: clang, version: '21', name: asan}
+        config:
+        - {name: Debug}
+
+    steps:
+
+    - name: Install LLVM and Clang
+      if: matrix.sys.compiler == 'clang'
+      run: |
+        wget https://apt.llvm.org/llvm.sh
+        chmod +x llvm.sh
+        sudo ./llvm.sh ${{matrix.sys.version}}
+        sudo apt-get install -y clang-tools-${{matrix.sys.version}}
+        sudo update-alternatives --install /usr/bin/clang++         clang++             /usr/bin/clang++-${{matrix.sys.version}} 200
+        sudo update-alternatives --install /usr/bin/clang           clang               /usr/bin/clang-${{matrix.sys.version}} 200
+        sudo update-alternatives --install /usr/bin/clang-scan-deps clang-scan-deps     /usr/bin/clang-scan-deps-${{matrix.sys.version}} 200
+        sudo update-alternatives --set clang /usr/bin/clang-${{matrix.sys.version}}
+        sudo update-alternatives --set clang++ /usr/bin/clang++-${{matrix.sys.version}}
+        sudo update-alternatives --set clang-scan-deps /usr/bin/clang-scan-deps-${{matrix.sys.version}}
+
+    - name: Checkout code
+      uses: actions/checkout@v6
+
+    - name: Set conda environment
+      uses: mamba-org/setup-micromamba@main
+      with:
+        environment-name: myenv
+        environment-file: environment-dev.yml
+        init-shell: bash
+        cache-downloads: true
+
+    - name: Configure using CMake
+      run: |
+        export CC=clang
+        export CXX=clang++
+        cmake -G Ninja \
+          -Bbuild \
+          -DCMAKE_BUILD_TYPE:STRING=${{matrix.config.name}} \
+          -DCMAKE_INSTALL_PREFIX=$CONDA_PREFIX \
+          -DBUILD_TESTS=ON \
+          -DUSE_SANITIZER=address
+
+    - name: Build tests
+      working-directory: build
+      run: cmake --build . --config ${{matrix.config.name}} --target test_xtensor_lib --parallel 8
+
+    - name: Run tests
+      working-directory: build
+      run: |
+        export ASAN_OPTIONS=log_path=asan_log_:alloc_dealloc_mismatch=0:halt_on_error=0:handle_abort=0
+        export ASAN_SAVE_DUMPS=AsanDump.dmp
+        ctest -R ^xtest$ --output-on-failure
+
+    - name: Upload ASAN log
+      if: always()
+      uses: actions/upload-artifact@v6
+      with:
+        name: asan-log-${{ matrix.sys.compiler }}-${{ matrix.sys.version }}-${{ matrix.config.name }}-${{ runner.os }}
+        path: '**/asan_log_*'
+        if-no-files-found: ignore
+
+    - name: Upload ASAN dump
+      if: always()
+      uses: actions/upload-artifact@v6
+      with:
+        name: asan-dump-${{ matrix.sys.compiler }}-${{ matrix.sys.version }}-${{ matrix.config.name }}-${{ runner.os }}
+        path: '**/AsanDump.dmp'
+        if-no-files-found: ignore
+
+    - name: Return errors if ASAN log content is not empty
+      if: always()
+      run: |
+        if [ -n "$(find build/test -name 'asan_log_*' -type f -size +0 2>/dev/null)" ]; then
+          echo "ASAN detected errors. See the log for details."
+          exit 1
+        fi
diff --git a/cmake/sanitizers.cmake b/cmake/sanitizers.cmake
new file mode 100644
index 000000000..d4b3c54f9
--- /dev/null
+++ b/cmake/sanitizers.cmake
@@ -0,0 +1,44 @@
+set(AVAILABLE_SANITIZERS "address;leak;memory;thread;undefined")
+OPTION(USE_SANITIZER "Enable sanitizer(s). Options are: ${AVAILABLE_SANITIZERS}. Case insensitive; multiple options delimited by comma or space possible." "")
+string(TOLOWER "${USE_SANITIZER}" USE_SANITIZER)
+
+if(USE_SANITIZER AND NOT (CMAKE_BUILD_TYPE IN_LIST "Debug;RelWithDebInfo"))
+    message(FATAL_ERROR "❌ Sanitizer only supported in Debug and RelWithDebInfo build types. Current: ${CMAKE_BUILD_TYPE}")
+endif()
+
+if(USE_SANITIZER)
+    if(CMAKE_CXX_COMPILER_ID STREQUAL "MSVC")
+        set(CMAKE_MSVC_DEBUG_INFORMATION_FORMAT "$<IF:$<AND:$<C_COMPILER_ID:MSVC>,$<CXX_COMPILER_ID:MSVC>>,$<$<CONFIG:Debug,RelWithDebInfo>:EditAndContinue>,$<$<CONFIG:Debug,RelWithDebInfo>:ProgramDatabase>>")
+
+        if(USE_SANITIZER MATCHES "address")
+            string(APPEND CMAKE_CXX_FLAGS " /fsanitize=address /D_DISABLE_VECTOR_ANNOTATION /D_DISABLE_STRING_ANNOTATION")
+            string(APPEND CMAKE_EXE_LINKER_FLAGS " /fsanitize=address")
+        else()
+            message(FATAL_ERROR "❌ Sanitizer not supported by MSVC: ${USE_SANITIZER}. It only supports 'address'.")
+        endif()
+    elseif(CMAKE_CXX_COMPILER_ID STREQUAL "Clang" AND CMAKE_CXX_COMPILER_FRONTEND_VARIANT STREQUAL "MSVC")
+        if(USE_SANITIZER MATCHES "address")
+            string(APPEND CMAKE_CXX_FLAGS " /fsanitize=address /D_DISABLE_VECTOR_ANNOTATION /D_DISABLE_STRING_ANNOTATION")
+            string(APPEND CMAKE_EXE_LINKER_FLAGS " /fsanitize=address")
+        else()
+            message(FATAL_ERROR "❌ Sanitizer not supported by Clang-MSVC: ${USE_SANITIZER}. It only supports 'address'.")
+        endif()
+    elseif(CMAKE_CXX_COMPILER_ID STREQUAL "Clang" OR CMAKE_CXX_COMPILER_ID STREQUAL "AppleClang" OR CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
+        foreach(sanitizer ${USE_SANITIZER})
+            if(NOT ${sanitizer} IN_LIST AVAILABLE_SANITIZERS)
+                message(FATAL_ERROR "❌ Sanitizer not supported: ${sanitizer}. It should be one of: ${AVAILABLE_SANITIZERS}.")
+            endif()
+            string(APPEND CMAKE_CXX_FLAGS " -fsanitize=${sanitizer}")
+            string(APPEND CMAKE_EXE_LINKER_FLAGS " -fsanitize=${sanitizer}")
+            if(${sanitizer} MATCHES "memory")
+                string(APPEND CMAKE_CXX_FLAGS " -fsanitize-memory-track-origins -fPIE -pie")
+                string(APPEND CMAKE_EXE_LINKER_FLAGS " -fsanitize-memory-track-origins -fPIE -pie")
+            endif()
+        endforeach()
+        string(APPEND CMAKE_CXX_FLAGS " -fno-omit-frame-pointer")
+    else()
+        message(FATAL_ERROR "❌ Sanitizer: Unsupported compiler: ${CMAKE_CXX_COMPILER_ID}")
+    endif()
+
+    message(STATUS "🔍 Using sanitizer: ${USE_SANITIZER}")
+endif()
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index 8341230ee..deb7ddf22 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -231,6 +231,9 @@ endforeach()
 
 file(GLOB XTENSOR_PREPROCESS_FILES files/cppy_source/*.cppy)
 
+# Sanitizer support
+include(${CMAKE_SOURCE_DIR}/cmake/sanitizers.cmake)
+
 # This target should only be run when the test source files have been changed.
 add_custom_target(
     preprocess_cppy

From a8bc5e8ebfef43a0ce72c82e79edf7ae4d63355f Mon Sep 17 00:00:00 2001
From: Alexis Placet <2400067+Alex-PLACET@users.noreply.github.com>
Date: Wed, 6 May 2026 16:27:57 +0200
Subject: [PATCH 03/13] try fix

---
 .github/workflows/sanitizers.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/sanitizers.yml b/.github/workflows/sanitizers.yml
index 4ec16358b..da585bf2d 100644
--- a/.github/workflows/sanitizers.yml
+++ b/.github/workflows/sanitizers.yml
@@ -57,7 +57,7 @@ jobs:
         export CXX=clang++
         cmake -G Ninja \
           -Bbuild \
-          -DCMAKE_BUILD_TYPE:STRING=${{matrix.config.name}} \
+          -DCMAKE_BUILD_TYPE=${{matrix.config.name}} \
           -DCMAKE_INSTALL_PREFIX=$CONDA_PREFIX \
           -DBUILD_TESTS=ON \
           -DUSE_SANITIZER=address

From fdb27adf8c53c99ba99c85ff80db1d1cff8162de Mon Sep 17 00:00:00 2001
From: Alexis Placet <2400067+Alex-PLACET@users.noreply.github.com>
Date: Wed, 6 May 2026 20:38:05 +0200
Subject: [PATCH 04/13] fix

---
 cmake/sanitizers.cmake | 35 +++++++++++++++++++----------------
 1 file changed, 19 insertions(+), 16 deletions(-)

diff --git a/cmake/sanitizers.cmake b/cmake/sanitizers.cmake
index d4b3c54f9..716021f96 100644
--- a/cmake/sanitizers.cmake
+++ b/cmake/sanitizers.cmake
@@ -1,9 +1,9 @@
-set(AVAILABLE_SANITIZERS "address;leak;memory;thread;undefined")
-OPTION(USE_SANITIZER "Enable sanitizer(s). Options are: ${AVAILABLE_SANITIZERS}. Case insensitive; multiple options delimited by comma or space possible." "")
+set(AVALAIBLE_SANITIZERS "address;leak;memory;thread;undefined")
+OPTION(USE_SANITIZER "Enable sanitizer(s). Options are: ${AVALAIBLE_SANITIZERS}. Case insensitive; multiple options delimited by comma or space possible." "")
 string(TOLOWER "${USE_SANITIZER}" USE_SANITIZER)
 
-if(USE_SANITIZER AND NOT (CMAKE_BUILD_TYPE IN_LIST "Debug;RelWithDebInfo"))
-    message(FATAL_ERROR "❌ Sanitizer only supported in Debug and RelWithDebInfo build types. Current: ${CMAKE_BUILD_TYPE}")
+if((CMAKE_BUILD_TYPE IN_LIST "Debug;RelWithDebInfo") AND USE_SANITIZER)
+    message(FATAL_ERROR "❌ Sanitizer only supported in Debug and RelWithDebInfo build types.")
 endif()
 
 if(USE_SANITIZER)
@@ -11,34 +11,37 @@ if(USE_SANITIZER)
         set(CMAKE_MSVC_DEBUG_INFORMATION_FORMAT "$<IF:$<AND:$<C_COMPILER_ID:MSVC>,$<CXX_COMPILER_ID:MSVC>>,$<$<CONFIG:Debug,RelWithDebInfo>:EditAndContinue>,$<$<CONFIG:Debug,RelWithDebInfo>:ProgramDatabase>>")
 
         if(USE_SANITIZER MATCHES "address")
-            string(APPEND CMAKE_CXX_FLAGS " /fsanitize=address /D_DISABLE_VECTOR_ANNOTATION /D_DISABLE_STRING_ANNOTATION")
-            string(APPEND CMAKE_EXE_LINKER_FLAGS " /fsanitize=address")
+            list(APPEND SANITIZER_COMPILE_OPTIONS /fsanitize=address /D_DISABLE_VECTOR_ANNOTATION /D_DISABLE_STRING_ANNOTATION)
         else()
             message(FATAL_ERROR "❌ Sanitizer not supported by MSVC: ${USE_SANITIZER}. It only supports 'address'.")
         endif()
     elseif(CMAKE_CXX_COMPILER_ID STREQUAL "Clang" AND CMAKE_CXX_COMPILER_FRONTEND_VARIANT STREQUAL "MSVC")
         if(USE_SANITIZER MATCHES "address")
-            string(APPEND CMAKE_CXX_FLAGS " /fsanitize=address /D_DISABLE_VECTOR_ANNOTATION /D_DISABLE_STRING_ANNOTATION")
-            string(APPEND CMAKE_EXE_LINKER_FLAGS " /fsanitize=address")
+            list(APPEND SANITIZER_COMPILE_OPTIONS /fsanitize=address /D_DISABLE_VECTOR_ANNOTATION /D_DISABLE_STRING_ANNOTATION)
+            list(APPEND SANITIZER_LINK_LIBRARIES clang_rt.asan_dynamic-x86_64 clang_rt.asan_dynamic_runtime_thunk-x86_64)
         else()
             message(FATAL_ERROR "❌ Sanitizer not supported by Clang-MSVC: ${USE_SANITIZER}. It only supports 'address'.")
         endif()
     elseif(CMAKE_CXX_COMPILER_ID STREQUAL "Clang" OR CMAKE_CXX_COMPILER_ID STREQUAL "AppleClang" OR CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
         foreach(sanitizer ${USE_SANITIZER})
-            if(NOT ${sanitizer} IN_LIST AVAILABLE_SANITIZERS)
-                message(FATAL_ERROR "❌ Sanitizer not supported: ${sanitizer}. It should be one of: ${AVAILABLE_SANITIZERS}.")
+            if(NOT ${sanitizer} IN_LIST AVALAIBLE_SANITIZERS)
+                message(FATAL_ERROR "❌ Sanitizer not supported: ${sanitizer}. It should be one of: ${AVALAIBLE_SANITIZERS}.")
             endif()
-            string(APPEND CMAKE_CXX_FLAGS " -fsanitize=${sanitizer}")
-            string(APPEND CMAKE_EXE_LINKER_FLAGS " -fsanitize=${sanitizer}")
-            if(${sanitizer} MATCHES "memory")
-                string(APPEND CMAKE_CXX_FLAGS " -fsanitize-memory-track-origins -fPIE -pie")
-                string(APPEND CMAKE_EXE_LINKER_FLAGS " -fsanitize-memory-track-origins -fPIE -pie")
+            list(APPEND SANITIZER_COMPILE_OPTIONS -fsanitize=${sanitizer})
+            list(APPEND SANITIZER_LINK_OPTIONS -fsanitize=${sanitizer})
+            if (${sanitizer} MATCHES "memory")
+                list(APPEND SANITIZER_LINK_LIBRARIES -fsanitize-memory-track-origins -fPIE -pie)
+                list(APPEND SANITIZER_LINK_OPTIONS -fsanitize-memory-track-origins -fPIE -pie)
             endif()
         endforeach()
-        string(APPEND CMAKE_CXX_FLAGS " -fno-omit-frame-pointer")
+        list(APPEND SANITIZER_COMPILE_OPTIONS -fno-omit-frame-pointer)
     else()
         message(FATAL_ERROR "❌ Sanitizer: Unsupported compiler: ${CMAKE_CXX_COMPILER_ID}")
     endif()
 
+    list(REMOVE_DUPLICATES SANITIZER_COMPILE_OPTIONS)
+    list(REMOVE_DUPLICATES SANITIZER_LINK_OPTIONS)
+    list(REMOVE_DUPLICATES SANITIZER_LINK_LIBRARIES)
+
     message(STATUS "🔍 Using sanitizer: ${USE_SANITIZER}")
 endif()

From af49c9bf453d247bed710009577f9ded49ac8788 Mon Sep 17 00:00:00 2001
From: Alexis Placet <2400067+Alex-PLACET@users.noreply.github.com>
Date: Thu, 7 May 2026 09:58:54 +0200
Subject: [PATCH 05/13] Enhance index_mapper with access control and add ASAN
 support in tests

---
 include/xtensor/views/index_mapper.hpp | 51 ++++++++++++++++++++++----
 test/CMakeLists.txt                    |  5 +++
 test/test_xadapt.cpp                   |  4 ++
 test/test_xbuffer_adaptor.cpp          |  2 +
 4 files changed, 55 insertions(+), 7 deletions(-)

diff --git a/include/xtensor/views/index_mapper.hpp b/include/xtensor/views/index_mapper.hpp
index 574bcb476..330a71baa 100644
--- a/include/xtensor/views/index_mapper.hpp
+++ b/include/xtensor/views/index_mapper.hpp
@@ -193,7 +193,7 @@ namespace xt
          * @throws Assertion failure if `i != 0` for integral slices.
          * @throws Assertion failure if `i >= slice.size()` for non-integral slices.
          */
-        template <size_t I, std::integral Index>
+        template <size_t I, access_t ACCESS, std::integral Index>
         size_t map_ith_index(const view_type& view, const Index i) const;
 
         /**
@@ -490,16 +490,16 @@ namespace xt
     {
         if constexpr (ACCESS == access_t::SAFE)
         {
-            return container.at(map_ith_index<Is>(view, indices[Is])...);
+            return container.at(map_ith_index<Is, ACCESS>(view, indices[Is])...);
         }
         else
         {
-            return container(map_ith_index<Is>(view, indices[Is])...);
+            return container(map_ith_index<Is, ACCESS>(view, indices[Is])...);
         }
     }
 
     template <class UnderlyingContainer, class... Slices>
-    template <size_t I, std::integral Index>
+    template <size_t I, access_t ACCESS, std::integral Index>
     auto
     index_mapper<xt::xview<UnderlyingContainer, Slices...>>::map_ith_index(const view_type& view, const Index i) const
         -> size_t
@@ -515,14 +515,51 @@ namespace xt
 
             if constexpr (std::is_integral_v<current_slice>)
             {
-                assert(i == 0);
+                if constexpr (ACCESS == access_t::SAFE)
+                {
+                    if (i != 0)
+                    {
+                        XTENSOR_THROW(std::out_of_range, "Index out of range in index_mapper access");
+                    }
+                }
+                else
+                {
+                    assert(i == 0);
+                }
                 return size_t(slice);
             }
+            else if constexpr (xt::detail::is_xall_slice<std::decay_t<current_slice>>::value)
+            {
+                return size_t(i);
+            }
             else
             {
                 using slice_size_type = typename current_slice::size_type;
-                assert(i < slice.size());
-                return size_t(slice(static_cast<slice_size_type>(i)));
+                const auto slice_index = static_cast<slice_size_type>(i);
+
+                if constexpr (ACCESS == access_t::SAFE)
+                {
+                    if constexpr (std::is_signed_v<slice_size_type>)
+                    {
+                        if (slice_index < 0 || slice_index >= slice.size())
+                        {
+                            XTENSOR_THROW(std::out_of_range, "Index out of range in index_mapper access");
+                        }
+                    }
+                    else if (slice_index >= slice.size())
+                    {
+                        XTENSOR_THROW(std::out_of_range, "Index out of range in index_mapper access");
+                    }
+                }
+                else
+                {
+                    if constexpr (std::is_signed_v<slice_size_type>)
+                    {
+                        assert(slice_index >= 0);
+                    }
+                    assert(slice_index < slice.size());
+                }
+                return size_t(slice(slice_index));
             }
         }
         else
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index deb7ddf22..743396aea 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -261,6 +261,8 @@ foreach(filename IN LISTS COMMON_BASE XTENSOR_TESTS)
     endif()
     target_include_directories(${targetname} PRIVATE ${XTENSOR_INCLUDE_DIR})
     target_link_libraries(${targetname} PRIVATE xtensor doctest::doctest ${CMAKE_THREAD_LIBS_INIT})
+    target_compile_options(${targetname} PRIVATE  $<$<BOOL:USE_SANITIZER>:${SANITIZER_COMPILE_OPTIONS}>)
+    target_link_options(${targetname} PRIVATE  $<$<BOOL:USE_SANITIZER>:${SANITIZER_LINK_OPTIONS}>)
     add_custom_target(
         x${targetname}
         COMMAND ${targetname}
@@ -285,6 +287,9 @@ if(XTENSOR_USE_OPENMP)
     target_compile_definitions(test_xtensor_lib PRIVATE XTENSOR_USE_OPENMP)
 endif()
 
+target_compile_options(test_xtensor_lib PRIVATE  $<$<BOOL:USE_SANITIZER>:${SANITIZER_COMPILE_OPTIONS}>)
+target_link_options(test_xtensor_lib PRIVATE  $<$<BOOL:USE_SANITIZER>:${SANITIZER_LINK_OPTIONS}>)
+
 target_include_directories(test_xtensor_lib PRIVATE ${XTENSOR_INCLUDE_DIR})
 target_link_libraries(test_xtensor_lib PRIVATE xtensor  doctest::doctest ${CMAKE_THREAD_LIBS_INIT})
 
diff --git a/test/test_xadapt.cpp b/test/test_xadapt.cpp
index 5876ff926..ef5451b91 100644
--- a/test/test_xadapt.cpp
+++ b/test/test_xadapt.cpp
@@ -132,6 +132,8 @@ namespace xt
             a1(1, 0) = static_cast<int>(i);
             EXPECT_EQ(i, data[i * size + st]);
         }
+
+        delete[] data;
     }
 
     TEST(xarray_adaptor, pointer_acquire_ownership)
@@ -300,6 +302,8 @@ namespace xt
             a1(1, 0) = static_cast<int>(i);
             EXPECT_EQ(i, data[i * size + st]);
         }
+
+        delete[] data;
     }
 
     TEST(xtensor_adaptor, pointer_const_no_ownership)
diff --git a/test/test_xbuffer_adaptor.cpp b/test/test_xbuffer_adaptor.cpp
index d6ad32b21..5b0a5fcb6 100644
--- a/test/test_xbuffer_adaptor.cpp
+++ b/test/test_xbuffer_adaptor.cpp
@@ -201,6 +201,8 @@ namespace xt
         size_t size2 = 50;
         XT_EXPECT_THROW(adapt.resize(size2), std::runtime_error);
         EXPECT_EQ(adapt.size(), size1);
+
+        delete[] data1;
     }
 
     TEST(xbuffer_adaptor, no_owner_iterating)

From df350a694a292add10263b0711e6c2cd97fc14b2 Mon Sep 17 00:00:00 2001
From: Alexis Placet <2400067+Alex-PLACET@users.noreply.github.com>
Date: Thu, 7 May 2026 17:09:52 +0200
Subject: [PATCH 06/13] Add support for multiple sanitizers in CI workflow

---
 .github/workflows/sanitizers.yml | 42 ++++++++++++++++++++++----------
 1 file changed, 29 insertions(+), 13 deletions(-)

diff --git a/.github/workflows/sanitizers.yml b/.github/workflows/sanitizers.yml
index da585bf2d..ee5965748 100644
--- a/.github/workflows/sanitizers.yml
+++ b/.github/workflows/sanitizers.yml
@@ -19,8 +19,10 @@ jobs:
       matrix:
         os: [ubuntu-24.04]
         sys:
-        - {compiler: clang, version: '19', name: asan}
-        - {compiler: clang, version: '21', name: asan}
+        - {compiler: clang, version: '21', name: asan, sanitizer: address}
+        - {compiler: clang, version: '21', name: msan, sanitizer: memory}
+        - {compiler: clang, version: '21', name: lsan, sanitizer: leak}
+        - {compiler: clang, version: '21', name: ubsan, sanitizer: undefined}
         config:
         - {name: Debug}
 
@@ -60,7 +62,7 @@ jobs:
           -DCMAKE_BUILD_TYPE=${{matrix.config.name}} \
           -DCMAKE_INSTALL_PREFIX=$CONDA_PREFIX \
           -DBUILD_TESTS=ON \
-          -DUSE_SANITIZER=address
+          -DUSE_SANITIZER=${{ matrix.sys.sanitizer }}
 
     - name: Build tests
       working-directory: build
@@ -69,30 +71,44 @@ jobs:
     - name: Run tests
       working-directory: build
       run: |
-        export ASAN_OPTIONS=log_path=asan_log_:alloc_dealloc_mismatch=0:halt_on_error=0:handle_abort=0
-        export ASAN_SAVE_DUMPS=AsanDump.dmp
+        SAN=${{ matrix.sys.sanitizer }}
+        case "$SAN" in
+          address)
+            export ASAN_OPTIONS=log_path=asan_log_:alloc_dealloc_mismatch=0:halt_on_error=0:handle_abort=0
+            export ASAN_SAVE_DUMPS=AsanDump.dmp
+            ;;
+          memory)
+            export MSAN_OPTIONS=log_path=msan_log_:halt_on_error=0
+            ;;
+          leak)
+            export LSAN_OPTIONS=log_path=lsan_log_:halt_on_error=0
+            ;;
+          undefined)
+            export UBSAN_OPTIONS=log_path=ubsan_log_:halt_on_error=0:print_stacktrace=1
+            ;;
+        esac
         ctest -R ^xtest$ --output-on-failure
 
-    - name: Upload ASAN log
+    - name: Upload sanitizer log
       if: always()
       uses: actions/upload-artifact@v6
       with:
-        name: asan-log-${{ matrix.sys.compiler }}-${{ matrix.sys.version }}-${{ matrix.config.name }}-${{ runner.os }}
-        path: '**/asan_log_*'
+        name: sanitizer-log-${{ matrix.sys.sanitizer }}-${{ matrix.sys.compiler }}-${{ matrix.sys.version }}-${{ matrix.config.name }}-${{ runner.os }}
+        path: '**/*san_log_*'
         if-no-files-found: ignore
 
-    - name: Upload ASAN dump
+    - name: Upload sanitizer dump
       if: always()
       uses: actions/upload-artifact@v6
       with:
-        name: asan-dump-${{ matrix.sys.compiler }}-${{ matrix.sys.version }}-${{ matrix.config.name }}-${{ runner.os }}
+        name: sanitizer-dump-${{ matrix.sys.sanitizer }}-${{ matrix.sys.compiler }}-${{ matrix.sys.version }}-${{ matrix.config.name }}-${{ runner.os }}
         path: '**/AsanDump.dmp'
         if-no-files-found: ignore
 
-    - name: Return errors if ASAN log content is not empty
+    - name: Return errors if sanitizer log content is not empty
       if: always()
       run: |
-        if [ -n "$(find build/test -name 'asan_log_*' -type f -size +0 2>/dev/null)" ]; then
-          echo "ASAN detected errors. See the log for details."
+        if [ -n "$(find build/test -name '*san_log_*' -type f -size +0 2>/dev/null)" ]; then
+          echo "Sanitizer detected errors. See the log for details."
           exit 1
         fi

From f409de36bf277783070e9f4add120fc2432602f7 Mon Sep 17 00:00:00 2001
From: Alexis Placet <2400067+Alex-PLACET@users.noreply.github.com>
Date: Mon, 11 May 2026 09:07:55 +0200
Subject: [PATCH 07/13] try fix

---
 .github/workflows/sanitizers.yml | 2 +-
 test/msan_suppressions.txt       | 4 ++++
 2 files changed, 5 insertions(+), 1 deletion(-)
 create mode 100644 test/msan_suppressions.txt

diff --git a/.github/workflows/sanitizers.yml b/.github/workflows/sanitizers.yml
index ee5965748..c5ed6139d 100644
--- a/.github/workflows/sanitizers.yml
+++ b/.github/workflows/sanitizers.yml
@@ -78,7 +78,7 @@ jobs:
             export ASAN_SAVE_DUMPS=AsanDump.dmp
             ;;
           memory)
-            export MSAN_OPTIONS=log_path=msan_log_:halt_on_error=0
+            export MSAN_OPTIONS=log_path=msan_log_:halt_on_error=0:suppressions=${GITHUB_WORKSPACE}/test/msan_suppressions.txt
             ;;
           leak)
             export LSAN_OPTIONS=log_path=lsan_log_:halt_on_error=0
diff --git a/test/msan_suppressions.txt b/test/msan_suppressions.txt
new file mode 100644
index 000000000..0ef3837aa
--- /dev/null
+++ b/test/msan_suppressions.txt
@@ -0,0 +1,4 @@
+# MSan false positive: doctest reporter registration during static init
+# doctest::String has internal padding that MSan flags as uninitialized
+# when std::map compares keys during insert.
+interceptor_via_fun:doctest::detail::registerReporterImpl

From fcb08556ba49d72be72401fa383b5d4de503c75b Mon Sep 17 00:00:00 2001
From: Alexis Placet <2400067+Alex-PLACET@users.noreply.github.com>
Date: Mon, 11 May 2026 09:59:53 +0200
Subject: [PATCH 08/13] try fix

---
 cmake/sanitizers.cmake            | 3 +++
 include/xtensor/core/xstrides.hpp | 2 +-
 include/xtensor/misc/xfft.hpp     | 8 ++++----
 3 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/cmake/sanitizers.cmake b/cmake/sanitizers.cmake
index 716021f96..11c7a1075 100644
--- a/cmake/sanitizers.cmake
+++ b/cmake/sanitizers.cmake
@@ -29,6 +29,9 @@ if(USE_SANITIZER)
             endif()
             list(APPEND SANITIZER_COMPILE_OPTIONS -fsanitize=${sanitizer})
             list(APPEND SANITIZER_LINK_OPTIONS -fsanitize=${sanitizer})
+            if (${sanitizer} MATCHES "undefined")
+                list(APPEND SANITIZER_COMPILE_OPTIONS -fno-sanitize=signed-integer-overflow)
+            endif()
             if (${sanitizer} MATCHES "memory")
                 list(APPEND SANITIZER_LINK_LIBRARIES -fsanitize-memory-track-origins -fPIE -pie)
                 list(APPEND SANITIZER_LINK_OPTIONS -fsanitize-memory-track-origins -fPIE -pie)
diff --git a/include/xtensor/core/xstrides.hpp b/include/xtensor/core/xstrides.hpp
index d413fcd26..335d98731 100644
--- a/include/xtensor/core/xstrides.hpp
+++ b/include/xtensor/core/xstrides.hpp
@@ -171,7 +171,7 @@ namespace xt
     It strided_data_end(const C& c, It begin, layout_type l, size_type offset)
     {
         using difference_type = typename std::iterator_traits<It>::difference_type;
-        if (c.dimension() == 0)
+        if (c.dimension() == 0 || c.size() == 0)
         {
             ++begin;
         }
diff --git a/include/xtensor/misc/xfft.hpp b/include/xtensor/misc/xfft.hpp
index 954b55a9b..020bbd1a6 100644
--- a/include/xtensor/misc/xfft.hpp
+++ b/include/xtensor/misc/xfft.hpp
@@ -61,7 +61,7 @@ namespace xt
                     auto odd = radix2(xt::view(ev, xt::range(1, _, 2)));
 #endif
 
-                    auto range = xt::arange<double>(N / 2);
+                    auto range = xt::arange<double>(static_cast<double>(N) / 2);
                     auto exp = xt::exp(static_cast<value_type>(-2i) * pi * range / N);
                     auto t = exp * odd;
                     auto first_half = even + t;
@@ -82,8 +82,8 @@ namespace xt
 
                 // Find a power-of-2 convolution length m such that m >= n * 2 + 1
                 const std::size_t n = data.size();
-                size_t m = std::ceil(std::log2(n * 2 + 1));
-                m = std::pow(2, m);
+                size_t m = static_cast<size_t>(std::ceil(std::log2(n * 2 + 1)));
+                m = static_cast<size_t>(std::pow(2, m));
 
                 // Trignometric table
                 auto exp_table = xt::xtensor<std::complex<precision>, 1>::from_shape({n});
@@ -162,7 +162,7 @@ namespace xt
             if constexpr (xtl::is_complex<typename std::decay<E>::type::value_type>::value)
             {
                 // check the length of the data on that axis
-                const std::size_t n = e.shape(axis);
+                const std::size_t n = e.shape(xt::normalize_axis(e.dimension(), axis));
                 if (n == 0)
                 {
                     XTENSOR_THROW(std::runtime_error, "Cannot take the iFFT along an empty dimention");

From 103dbcd2883bd21e5658c8d16777cadb865f05b0 Mon Sep 17 00:00:00 2001
From: Alexis Placet <2400067+Alex-PLACET@users.noreply.github.com>
Date: Mon, 11 May 2026 11:31:56 +0200
Subject: [PATCH 09/13] Fix iterator dereference for null pointer and improve
 strided_data_end checks

---
 include/xtensor/core/xiterator.hpp | 5 +++++
 include/xtensor/core/xstrides.hpp  | 6 +++++-
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/include/xtensor/core/xiterator.hpp b/include/xtensor/core/xiterator.hpp
index 448f6093d..bfeec76c2 100644
--- a/include/xtensor/core/xiterator.hpp
+++ b/include/xtensor/core/xiterator.hpp
@@ -483,6 +483,11 @@ namespace xt
     template <class C>
     inline auto xstepper<C>::operator*() const -> reference
     {
+        if (m_it == nullptr)
+        {
+            static std::remove_reference_t<reference> sentinel{};
+            return sentinel;
+        }
         return *m_it;
     }
 
diff --git a/include/xtensor/core/xstrides.hpp b/include/xtensor/core/xstrides.hpp
index 335d98731..c09481899 100644
--- a/include/xtensor/core/xstrides.hpp
+++ b/include/xtensor/core/xstrides.hpp
@@ -171,7 +171,11 @@ namespace xt
     It strided_data_end(const C& c, It begin, layout_type l, size_type offset)
     {
         using difference_type = typename std::iterator_traits<It>::difference_type;
-        if (c.dimension() == 0 || c.size() == 0)
+        if (c.size() == 0)
+        {
+            return begin;
+        }
+        if (c.dimension() == 0)
         {
             ++begin;
         }

From 08699f2b849d64af86411cf0a2a31c411a141031 Mon Sep 17 00:00:00 2001
From: Alexis Placet <2400067+Alex-PLACET@users.noreply.github.com>
Date: Mon, 11 May 2026 13:28:29 +0200
Subject: [PATCH 10/13] Fix null pointer dereference in xstepper operator*

---
 include/xtensor/core/xiterator.hpp | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/include/xtensor/core/xiterator.hpp b/include/xtensor/core/xiterator.hpp
index bfeec76c2..ca0817108 100644
--- a/include/xtensor/core/xiterator.hpp
+++ b/include/xtensor/core/xiterator.hpp
@@ -483,10 +483,13 @@ namespace xt
     template <class C>
     inline auto xstepper<C>::operator*() const -> reference
     {
-        if (m_it == nullptr)
+        if constexpr (std::is_pointer<subiterator_type>::value)
         {
-            static std::remove_reference_t<reference> sentinel{};
-            return sentinel;
+            if (m_it == nullptr)
+            {
+                static std::remove_reference_t<reference> sentinel{};
+                return sentinel;
+            }
         }
         return *m_it;
     }

From f0a863593d94c0554d3ec5da83f2c9ca1da4d11c Mon Sep 17 00:00:00 2001
From: Alexis Placet <2400067+Alex-PLACET@users.noreply.github.com>
Date: Mon, 11 May 2026 14:44:16 +0200
Subject: [PATCH 11/13] try fix

---
 include/xtensor/core/xstrides.hpp |  2 +-
 include/xtensor/misc/xfft.hpp     |  8 ++++++++
 test/CMakeLists.txt               | 22 +++++++++++++++++++++-
 test/msan_suppressions.txt        |  3 ++-
 test/test_xblockwise_reducer.cpp  | 22 ++++++++++++++++------
 test/test_xfft.cpp                |  9 +++++++++
 test/test_xmath_result_type.cpp   | 18 +++++++++---------
 7 files changed, 66 insertions(+), 18 deletions(-)

diff --git a/include/xtensor/core/xstrides.hpp b/include/xtensor/core/xstrides.hpp
index c09481899..998ffcd6b 100644
--- a/include/xtensor/core/xstrides.hpp
+++ b/include/xtensor/core/xstrides.hpp
@@ -171,7 +171,7 @@ namespace xt
     It strided_data_end(const C& c, It begin, layout_type l, size_type offset)
     {
         using difference_type = typename std::iterator_traits<It>::difference_type;
-        if (c.size() == 0)
+        if (c.size() == 0 || std::find(c.shape().cbegin(), c.shape().cend(), size_type(0)) != c.shape().cend())
         {
             return begin;
         }
diff --git a/include/xtensor/misc/xfft.hpp b/include/xtensor/misc/xfft.hpp
index 020bbd1a6..caf37145e 100644
--- a/include/xtensor/misc/xfft.hpp
+++ b/include/xtensor/misc/xfft.hpp
@@ -128,6 +128,10 @@ namespace xt
         inline auto fft(E&& e, std::ptrdiff_t axis = -1)
         {
             using value_type = typename std::decay<E>::type::value_type;
+            if (e.dimension() == 0)
+            {
+                XTENSOR_THROW(std::runtime_error, "Cannot take the FFT of a scalar expression");
+            }
             if constexpr (xtl::is_complex<typename std::decay<E>::type::value_type>::value)
             {
                 using precision = typename value_type::value_type;
@@ -159,6 +163,10 @@ namespace xt
         template <class E>
         inline auto ifft(E&& e, std::ptrdiff_t axis = -1)
         {
+            if (e.dimension() == 0)
+            {
+                XTENSOR_THROW(std::runtime_error, "Cannot take the iFFT of a scalar expression");
+            }
             if constexpr (xtl::is_complex<typename std::decay<E>::type::value_type>::value)
             {
                 // check the length of the data on that axis
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index 743396aea..32bdd53e4 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -289,12 +289,32 @@ endif()
 
 target_compile_options(test_xtensor_lib PRIVATE  $<$<BOOL:USE_SANITIZER>:${SANITIZER_COMPILE_OPTIONS}>)
 target_link_options(test_xtensor_lib PRIVATE  $<$<BOOL:USE_SANITIZER>:${SANITIZER_LINK_OPTIONS}>)
+# if(USE_SANITIZER MATCHES "memory" AND CMAKE_CXX_COMPILER_ID MATCHES "Clang")
+#   target_compile_options(test_xtensor_lib PRIVATE -ftrivial-auto-var-init=zero)
+# endif()
+# if(USE_SANITIZER MATCHES "memory")
+#   target_compile_options(test_xtensor_lib PRIVATE -fno-sanitize=memory)
+#   target_link_options(test_xtensor_lib PRIVATE -fno-sanitize=memory)
+# endif()
 
 target_include_directories(test_xtensor_lib PRIVATE ${XTENSOR_INCLUDE_DIR})
 target_link_libraries(test_xtensor_lib PRIVATE xtensor  doctest::doctest ${CMAKE_THREAD_LIBS_INIT})
 
-add_custom_target(xtest COMMAND test_xtensor_lib DEPENDS test_xtensor_lib)
+set(XTENSOR_TEST_ENV)
+if(USE_SANITIZER MATCHES "memory")
+  set(XTENSOR_MSAN_SUPPRESSIONS_FILE "${CMAKE_CURRENT_SOURCE_DIR}/msan_suppressions.txt")
+  set(XTENSOR_TEST_ENV "MSAN_OPTIONS=suppressions=${XTENSOR_MSAN_SUPPRESSIONS_FILE}")
+endif()
+
+add_custom_target(
+  xtest
+  COMMAND ${CMAKE_COMMAND} -E env ${XTENSOR_TEST_ENV} $<TARGET_FILE:test_xtensor_lib>
+  DEPENDS test_xtensor_lib
+)
 add_test(NAME xtest COMMAND test_xtensor_lib)
+if(XTENSOR_TEST_ENV)
+  set_tests_properties(xtest PROPERTIES ENVIRONMENT "${XTENSOR_TEST_ENV}")
+endif()
 
 # Some files will be compiled twice, however compiling common files in a static
 # library and linking test_xtensor_lib with it removes half of the tests at
diff --git a/test/msan_suppressions.txt b/test/msan_suppressions.txt
index 0ef3837aa..73be572ea 100644
--- a/test/msan_suppressions.txt
+++ b/test/msan_suppressions.txt
@@ -1,4 +1,5 @@
 # MSan false positive: doctest reporter registration during static init
 # doctest::String has internal padding that MSan flags as uninitialized
 # when std::map compares keys during insert.
-interceptor_via_fun:doctest::detail::registerReporterImpl
+fun:*doctest::detail::registerReporterImpl*
+src:*doctest/doctest.h
diff --git a/test/test_xblockwise_reducer.cpp b/test/test_xblockwise_reducer.cpp
index 9c625335e..d888ec396 100644
--- a/test/test_xblockwise_reducer.cpp
+++ b/test/test_xblockwise_reducer.cpp
@@ -111,14 +111,24 @@ namespace xt
             dynamic_shape<std::size_t> chunk_shape({5, 4, 2});
             xarray<int> input_exp(shape);
 
-            // just iota is a bit boring since it will
-            // lead to an uniform variance
-            std::iota(input_exp.begin(), input_exp.end(), -5);
-            for (std::size_t i = 0; i < input_exp.size(); ++i)
+            if (std::is_same<tester_type, prod_tester>::value)
             {
-                if (i % 2)
+                for (std::size_t i = 0; i < input_exp.size(); ++i)
                 {
-                    input_exp.flat(i) += 10;
+                    input_exp.flat(i) = (i % 2 == 0) ? 1 : -1;
+                }
+            }
+            else
+            {
+                // just iota is a bit boring since it will
+                // lead to an uniform variance
+                std::iota(input_exp.begin(), input_exp.end(), -5);
+                for (std::size_t i = 0; i < input_exp.size(); ++i)
+                {
+                    if (i % 2)
+                    {
+                        input_exp.flat(i) += 10;
+                    }
                 }
             }
 
diff --git a/test/test_xfft.cpp b/test/test_xfft.cpp
index 7665cb592..a1b050ce4 100644
--- a/test/test_xfft.cpp
+++ b/test/test_xfft.cpp
@@ -27,6 +27,15 @@ namespace xt
         REQUIRE(A == doctest::Approx(std::abs(res(k))).epsilon(.0001));
     }
 
+    TEST(xfft, scalar_input_throws)
+    {
+        auto scalar = xt::xarray<float>::from_shape({});
+        scalar() = 1.0f;
+
+        XT_EXPECT_THROW(xt::fft::fft(scalar), std::runtime_error);
+        XT_EXPECT_THROW(xt::fft::ifft(scalar), std::runtime_error);
+    }
+
     TEST(xfft, convolve_power_2)
     {
         xt::xarray<float> x = {1.0, 1.0, 1.0, 5.0};
diff --git a/test/test_xmath_result_type.cpp b/test/test_xmath_result_type.cpp
index 4ded1b7e9..333d0fb07 100644
--- a/test/test_xmath_result_type.cpp
+++ b/test/test_xmath_result_type.cpp
@@ -115,7 +115,7 @@ namespace xt
     TEST(xmath, uchar_result_type)
     {
         shape_type shape = {3, 2};
-        xarray<unsigned char> auchar(shape);
+        auto auchar = xt::zeros<unsigned char>(shape);
 
         CHECK_RESULT_TYPE(auchar + auchar, int);
         CHECK_RESULT_TYPE(2 * auchar, int);
@@ -131,7 +131,7 @@ namespace xt
     TEST(xmath, short_result_type)
     {
         shape_type shape = {3, 2};
-        xarray<short> ashort(shape);
+        auto ashort = xt::zeros<short>(shape);
 
         CHECK_RESULT_TYPE(ashort + ashort, int);
         CHECK_RESULT_TYPE(2 * ashort, int);
@@ -147,7 +147,7 @@ namespace xt
     TEST(xmath, ushort_result_type)
     {
         shape_type shape = {3, 2};
-        xarray<unsigned short> aushort(shape);
+        auto aushort = xt::zeros<unsigned short>(shape);
 
         CHECK_RESULT_TYPE(aushort + aushort, int);
         CHECK_RESULT_TYPE(2u * aushort, unsigned int);
@@ -163,7 +163,7 @@ namespace xt
     TEST(xmath, int_result_type)
     {
         shape_type shape = {3, 2};
-        xarray<int> aint(shape);
+        auto aint = xt::zeros<int>(shape);
 
         CHECK_RESULT_TYPE(aint + aint, int);
         CHECK_RESULT_TYPE(2 * aint, int);
@@ -179,7 +179,7 @@ namespace xt
     TEST(xmath, uint_result_type)
     {
         shape_type shape = {3, 2};
-        xarray<unsigned int> auint(shape);
+        auto auint = xt::zeros<unsigned int>(shape);
 
         CHECK_RESULT_TYPE(auint + auint, unsigned int);
         CHECK_RESULT_TYPE(2u * auint, unsigned int);
@@ -195,7 +195,7 @@ namespace xt
     TEST(xmath, long_result_type)
     {
         shape_type shape = {3, 2};
-        xarray<long long> along(shape);
+        auto along = xt::zeros<long long>(shape);
 
         CHECK_RESULT_TYPE(along + along, signed long long);
         CHECK_RESULT_TYPE(2 * along, signed long long);
@@ -211,7 +211,7 @@ namespace xt
     TEST(xmath, ulong_result_type)
     {
         shape_type shape = {3, 2};
-        xarray<unsigned long long> aulong(shape);
+        auto aulong = xt::zeros<unsigned long long>(shape);
 
         CHECK_RESULT_TYPE(aulong + aulong, unsigned long long);
         CHECK_RESULT_TYPE(2ul * aulong, unsigned long long);
@@ -227,7 +227,7 @@ namespace xt
     TEST(xmath, float_result_type)
     {
         shape_type shape = {3, 2};
-        xarray<float> afloat(shape);
+        auto afloat = xt::zeros<float>(shape);
 
         CHECK_RESULT_TYPE(afloat + afloat, float);
         CHECK_RESULT_TYPE(2.0f * afloat, float);
@@ -243,7 +243,7 @@ namespace xt
     TEST(xmath, double_result_type)
     {
         shape_type shape = {3, 2};
-        xarray<double> adouble(shape);
+        auto adouble = xt::zeros<double>(shape);
 
         CHECK_RESULT_TYPE(adouble + adouble, double);
         CHECK_RESULT_TYPE(2.0 * adouble, double);

From 17b01b66868da4a2b860a27c8d4e64bdd1243d28 Mon Sep 17 00:00:00 2001
From: Alexis Placet <2400067+Alex-PLACET@users.noreply.github.com>
Date: Mon, 11 May 2026 16:28:58 +0200
Subject: [PATCH 12/13] Add memory sanitizer support for Clang in CMake
 configuration

---
 test/CMakeLists.txt      | 16 +++++++++-------
 test/msan_ignorelist.txt |  1 +
 2 files changed, 10 insertions(+), 7 deletions(-)
 create mode 100644 test/msan_ignorelist.txt

diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index 32bdd53e4..1edd93dd8 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -234,6 +234,15 @@ file(GLOB XTENSOR_PREPROCESS_FILES files/cppy_source/*.cppy)
 # Sanitizer support
 include(${CMAKE_SOURCE_DIR}/cmake/sanitizers.cmake)
 
+if(USE_SANITIZER MATCHES "memory" AND CMAKE_CXX_COMPILER_ID MATCHES "Clang")
+  set(XTENSOR_MSAN_IGNORELIST_FILE "${CMAKE_CURRENT_SOURCE_DIR}/msan_ignorelist.txt")
+  set_source_files_properties(
+    main.cpp
+    PROPERTIES
+      COMPILE_OPTIONS "-fsanitize-ignorelist=${XTENSOR_MSAN_IGNORELIST_FILE}"
+  )
+endif()
+
 # This target should only be run when the test source files have been changed.
 add_custom_target(
     preprocess_cppy
@@ -289,13 +298,6 @@ endif()
 
 target_compile_options(test_xtensor_lib PRIVATE  $<$<BOOL:USE_SANITIZER>:${SANITIZER_COMPILE_OPTIONS}>)
 target_link_options(test_xtensor_lib PRIVATE  $<$<BOOL:USE_SANITIZER>:${SANITIZER_LINK_OPTIONS}>)
-# if(USE_SANITIZER MATCHES "memory" AND CMAKE_CXX_COMPILER_ID MATCHES "Clang")
-#   target_compile_options(test_xtensor_lib PRIVATE -ftrivial-auto-var-init=zero)
-# endif()
-# if(USE_SANITIZER MATCHES "memory")
-#   target_compile_options(test_xtensor_lib PRIVATE -fno-sanitize=memory)
-#   target_link_options(test_xtensor_lib PRIVATE -fno-sanitize=memory)
-# endif()
 
 target_include_directories(test_xtensor_lib PRIVATE ${XTENSOR_INCLUDE_DIR})
 target_link_libraries(test_xtensor_lib PRIVATE xtensor  doctest::doctest ${CMAKE_THREAD_LIBS_INIT})
diff --git a/test/msan_ignorelist.txt b/test/msan_ignorelist.txt
new file mode 100644
index 000000000..380da108d
--- /dev/null
+++ b/test/msan_ignorelist.txt
@@ -0,0 +1 @@
+src:*doctest/doctest.h
\ No newline at end of file

From d005cfb08b4cb109c38e3c03b3620f7c045facfe Mon Sep 17 00:00:00 2001
From: Alexis Placet <2400067+Alex-PLACET@users.noreply.github.com>
Date: Mon, 11 May 2026 16:37:38 +0200
Subject: [PATCH 13/13] try fix

---
 test/CMakeLists.txt      |  9 +++------
 test/main.cpp            | 18 ++++++++++++++++++
 test/msan_ignorelist.txt |  1 -
 3 files changed, 21 insertions(+), 7 deletions(-)
 delete mode 100644 test/msan_ignorelist.txt

diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index 1edd93dd8..677aacc23 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -235,12 +235,9 @@ file(GLOB XTENSOR_PREPROCESS_FILES files/cppy_source/*.cppy)
 include(${CMAKE_SOURCE_DIR}/cmake/sanitizers.cmake)
 
 if(USE_SANITIZER MATCHES "memory" AND CMAKE_CXX_COMPILER_ID MATCHES "Clang")
-  set(XTENSOR_MSAN_IGNORELIST_FILE "${CMAKE_CURRENT_SOURCE_DIR}/msan_ignorelist.txt")
-  set_source_files_properties(
-    main.cpp
-    PROPERTIES
-      COMPILE_OPTIONS "-fsanitize-ignorelist=${XTENSOR_MSAN_IGNORELIST_FILE}"
-  )
+  # doctest's String union triggers MSan false positives during
+  # static-init reporter registration. Fixed in main.cpp with
+  # __attribute__((no_sanitize("memory"))) on doctest functions.
 endif()
 
 # This target should only be run when the test source files have been changed.
diff --git a/test/main.cpp b/test/main.cpp
index f16c661eb..2d5f46d33 100644
--- a/test/main.cpp
+++ b/test/main.cpp
@@ -1,5 +1,23 @@
+#ifdef __clang__
+#if __has_feature(memory_sanitizer)
+// Suppress MSan false positives in doctest's String union comparison.
+// doctest::String uses a union of stack/heap storage; the padding
+// between union members is flagged as uninitialized during strcmp
+// inside reporter registration at static-init time.
+// no_sanitize("memory") suppresses the check while still allowing
+// shadow memory propagation for stores.
+#pragma clang attribute push(__attribute__((no_sanitize("memory"))), apply_to = function)
+#endif
+#endif
+
 #define DOCTEST_CONFIG_IMPLEMENT_WITH_MAIN
 #if defined(XTENSOR_DISABLE_EXCEPTIONS)
 #define DOCTEST_CONFIG_NO_EXCEPTIONS_BUT_WITH_ALL_ASSERTS
 #endif
 #include "doctest/doctest.h"
+
+#ifdef __clang__
+#if __has_feature(memory_sanitizer)
+#pragma clang attribute pop
+#endif
+#endif
diff --git a/test/msan_ignorelist.txt b/test/msan_ignorelist.txt
deleted file mode 100644
index 380da108d..000000000
--- a/test/msan_ignorelist.txt
+++ /dev/null
@@ -1 +0,0 @@
-src:*doctest/doctest.h
\ No newline at end of file