From aabcee0af6e49522a8b70ecd2a42bba626769692 Mon Sep 17 00:00:00 2001
From: Toby Dylan Hocking <toby.dylan.hocking@usherbrooke.ca>
Date: Mon, 15 Sep 2025 14:04:20 -0400
Subject: [PATCH 01/17] activate macos checks

---
 .github/workflows/R-CMD-check.yaml | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/.github/workflows/R-CMD-check.yaml b/.github/workflows/R-CMD-check.yaml
index 34cbbbfab..aa92b2f87 100644
--- a/.github/workflows/R-CMD-check.yaml
+++ b/.github/workflows/R-CMD-check.yaml
@@ -26,7 +26,8 @@ jobs:
           # jobs (mainly test-coverage) to run on every commit in PRs so as to not slow down dev.
           # GHA does run these jobs concurrently but even so reducing the load seems like a good idea.
           - {os: windows-latest, r: 'devel'}
-          # - {os: macOS-latest, r: 'release'}    # test-coverage.yaml uses macOS
+          - {os: macos-14, r: 'release'}    
+          - {os: macos-15, r: 'release'}    
           # TODO(remotes>2.5.0): Use 24.04[noble?]
           - {os: ubuntu-22.04, r: 'release', rspm: "https://packagemanager.rstudio.com/cran/__linux__/jammy/latest"}
           # - {os: ubuntu-22.04,   r: 'devel', rspm: "https://packagemanager.rstudio.com/cran/__linux__/jammy/latest", http-user-agent: "R/4.1.0 (ubuntu-22.04) R (4.1.0 x86_64-pc-linux-gnu x86_64 linux-gnu) on GitHub Actions" }

From d0cb5cccb812aa3b5b921ff1bf8505109f4b6cef Mon Sep 17 00:00:00 2001
From: Toby Dylan Hocking <toby.dylan.hocking@usherbrooke.ca>
Date: Mon, 15 Sep 2025 14:26:52 -0400
Subject: [PATCH 02/17] try sysreqs

---
 .github/workflows/R-CMD-check.yaml | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/.github/workflows/R-CMD-check.yaml b/.github/workflows/R-CMD-check.yaml
index aa92b2f87..52525f12f 100644
--- a/.github/workflows/R-CMD-check.yaml
+++ b/.github/workflows/R-CMD-check.yaml
@@ -69,6 +69,12 @@ jobs:
             eval sudo $cmd
           done < <(Rscript -e 'writeLines(remotes::system_requirements("ubuntu", "22.04"))')
 
+      - name: Install R Package Build Dependencies on MacOS, from https://github.com/stan-dev/cmdstanr/pull/1072/files
+        if: runner.os == 'macOS'
+        uses: r-hub/actions/setup-r-sysreqs@v1
+        with:
+          type: 'minimal'
+
       - name: Install dependencies
         run: |
           remotes::install_deps(dependencies = TRUE)

From 82ad4a0b29bb1d15b07921c2c8e40eab7850e2d3 Mon Sep 17 00:00:00 2001
From: Toby Dylan Hocking <toby.dylan.hocking@usherbrooke.ca>
Date: Mon, 15 Sep 2025 14:39:26 -0400
Subject: [PATCH 03/17] cancel in progress false for testing

---
 .github/workflows/R-CMD-check.yaml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/R-CMD-check.yaml b/.github/workflows/R-CMD-check.yaml
index 52525f12f..2cbf2ed9e 100644
--- a/.github/workflows/R-CMD-check.yaml
+++ b/.github/workflows/R-CMD-check.yaml
@@ -10,7 +10,7 @@ name: R-CMD-check
 
 concurrency:
   group: ${{ github.event.pull_request.number || github.run_id }}
-  cancel-in-progress: true
+  cancel-in-progress: false
 
 jobs:
   R-CMD-check:

From eca2984a6fdae8ee204a2d9aac88631dcd490071 Mon Sep 17 00:00:00 2001
From: Toby Dylan Hocking <toby.dylan.hocking@usherbrooke.ca>
Date: Mon, 15 Sep 2025 14:43:39 -0400
Subject: [PATCH 04/17] try removing concurrency

---
 .github/workflows/R-CMD-check.yaml | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/.github/workflows/R-CMD-check.yaml b/.github/workflows/R-CMD-check.yaml
index 2cbf2ed9e..ac857d61b 100644
--- a/.github/workflows/R-CMD-check.yaml
+++ b/.github/workflows/R-CMD-check.yaml
@@ -8,10 +8,6 @@ on:
 
 name: R-CMD-check
 
-concurrency:
-  group: ${{ github.event.pull_request.number || github.run_id }}
-  cancel-in-progress: false
-
 jobs:
   R-CMD-check:
     runs-on: ${{ matrix.config.os }}

From 354b8d3fe5479e5359579c33e0664764a4a2291f Mon Sep 17 00:00:00 2001
From: Toby Dylan Hocking <toby.dylan.hocking@usherbrooke.ca>
Date: Mon, 15 Sep 2025 14:48:07 -0400
Subject: [PATCH 05/17] rm fail-fast

---
 .github/workflows/R-CMD-check.yaml | 1 -
 1 file changed, 1 deletion(-)

diff --git a/.github/workflows/R-CMD-check.yaml b/.github/workflows/R-CMD-check.yaml
index ac857d61b..d10a0f0c6 100644
--- a/.github/workflows/R-CMD-check.yaml
+++ b/.github/workflows/R-CMD-check.yaml
@@ -15,7 +15,6 @@ jobs:
     name: ${{ matrix.config.os }} (${{ matrix.config.r }})
 
     strategy:
-      fail-fast: true
       matrix:
         config:
           # Rdatatable has full-strength GLCI which runs after merge. So we just need a few

From 7b0cde48eec312ae5582843578176625f5f1ba07 Mon Sep 17 00:00:00 2001
From: Ivan K <krylov.r00t@gmail.com>
Date: Mon, 15 Sep 2025 22:48:09 +0300
Subject: [PATCH 06/17] Install custom OpenMP runtime for Apple clang 17

---
 .github/workflows/R-CMD-check.yaml | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/.github/workflows/R-CMD-check.yaml b/.github/workflows/R-CMD-check.yaml
index d10a0f0c6..6d4b11159 100644
--- a/.github/workflows/R-CMD-check.yaml
+++ b/.github/workflows/R-CMD-check.yaml
@@ -70,6 +70,18 @@ jobs:
         with:
           type: 'minimal'
 
+      - name: Intall and configure OpenMP runtime
+        if: runner.os == 'macOS'
+        run: |
+          if clang --version | grep 'clang version 17'; then
+            curl -O https://mac.r-project.org/openmp/openmp-19.1.0-darwin20-Release.tar.gz
+            sudo tar fvvxz openmp-19.1.0-darwin20-Release.tar.gz -C /
+            rm -f openmp-19.1.0-darwin20-Release.tar.gz
+            echo 'PKG_CFLAGS=-Xclang -fopenmp' >> $GITHUB_ENV
+            # Not the R-bundled -lomp, but our custom file installed just now
+            echo 'PKG_LIBS=/usr/local/lib/libomp.dylib' >> $GITHUB_ENV
+          fi # otherwise R-bundled runtime is fine
+
       - name: Install dependencies
         run: |
           remotes::install_deps(dependencies = TRUE)

From 80c14cdd19d2d8132169f9fdd2231cf53d5ad1fc Mon Sep 17 00:00:00 2001
From: Ivan K <krylov.r00t@gmail.com>
Date: Sat, 20 Sep 2025 11:24:53 +0300
Subject: [PATCH 07/17] configure: test OpenMP dynamic dispatch

On macOS, this detects OpenMP runtime incompatibilities, e.g. when
compiling with newer Apple clang and linking with R-bundled -lomp. In
this case, additionally consider a newer OpenMP runtime from
<https://mac.r-project.org/openmp/>.

Additionally, actually test with $(SHLIB_OPENMP_CFLAGS) and lift the
-fopenmp test outside the system-specific branches.
---
 configure       | 125 +++++++++++++++++++++---------------------------
 src/Makevars.in |   4 +-
 2 files changed, 57 insertions(+), 72 deletions(-)

diff --git a/configure b/configure
index c6492f54f..2acc77670 100755
--- a/configure
+++ b/configure
@@ -68,89 +68,78 @@ fi
 # Aside: ${SHLIB_OPENMP_CFLAGS} does not appear to be defined at this point according to Matt's testing on
 # Linux, and R CMD config SHLIB_OPENMP_CFLAGS also returns 'no information for variable'. That's not
 # inconsistent with R-exts$1.2.1.1, though, which states it's 'available for use in Makevars' (so not
-# necessarily here in configure). Hence use -fopenmp directly for this detection step.
+# necessarily here in configure).
 # printf not echo to pass checkbashisms w.r.t. to the \n
+# Specifically use schedule(dynamic) to distinguish incompatibilities in OpenMP runtime on macOS, #7318
 
 cat <<EOF > test-omp.c
 #include <omp.h>
-int main() {
-  return omp_get_num_threads();
+void test_openmp(int * result) {
+ int sum = 0;
+ #pragma omp parallel for reduction(+:sum) num_threads(2) schedule(dynamic)
+ for (int i = 1; i <= 2; ++i) sum += i;
+ *result = sum;
 }
 EOF
 
-detect_openmp () {
-
-  if [ "$(uname)" = "Linux" ]; then
-
-    printf "%s" "* checking if R installation supports OpenMP without any extra hints... "
-    if "${R_HOME}/bin/R" CMD SHLIB test-omp.c >> config.log 2>&1; then
-      echo "yes"
-      export R_OPENMP_ENABLED=1
-      return
-    else
-      echo "no"
-    fi
-
+test_openmp_variant () {
+  cflags="${PKG_CFLAGS:+${PKG_CFLAGS} }$1"
+  libs="${PKG_LIBS:+${PKG_LIBS} }$2"
+  printf "%s" "* checking if OpenMP works with CFLAGS='$cflags' LIBS='$libs'... "
+  if ! PKG_CFLAGS="$cflags" PKG_LIBS="$libs" "${R_HOME}"/bin/R CMD SHLIB --preclean --clean test-omp.c >>config.log 2>&1; then
+    echo "no"
+    return 1
+  fi
 
-    printf "%s" "* checking if R installation supports openmp with \"-fopenmp\" flag... "
-    if ${CC} ${CFLAGS} -fopenmp test-omp.c >> config.log 2>&1; then
-      echo "yes"
-      export PKG_CFLAGS="${PKG_CFLAGS} -fopenmp"
-      export R_OPENMP_ENABLED=1
-      return
-    else
-      echo "no"
-    fi
-  fi # uname=Linux
+  if ! "${R_HOME}"/bin/Rscript -e '
+dll <- paste0("test-omp", .Platform$dynlib.ext)
+dyn.load(dll)
+ans <- .C("test_openmp", ans = integer(1))$ans
+stopifnot(identical(ans, 3L))
+' >> config.log 2>&1; then
+    echo "no"
+    return 1
+  fi
 
-  if [ "$(uname)" = "Darwin" ]; then
+  export PKG_CFLAGS="${PKG_CFLAGS} ${1}"
+  export PKG_LIBS="${PKG_LIBS} ${2}"
+  export R_OPENMP_ENABLED=1
+  echo "yes"
+  return 0
+}
 
+detect_openmp () {
+  # OpenMP flags provided in environment variables or specified when configuring R? Does -fopenmp work?
+  test_openmp_variant '$(SHLIB_OPENMP_CFLAGS)' '$(SHLIB_OPENMP_CFLAGS)' \
+  || test_openmp_variant "" "" \
+  || test_openmp_variant -fopenmp -fopenmp \
+  && return
+
+  case "$(uname)" in
+  Darwin)
     # https://mac.r-project.org/openmp
-    printf "%s" "* checking if R installation supports OpenMP with \"-Xclang -fopenmp\" ... "
-    if CPPFLAGS="${CPPFLAGS} -Xclang -fopenmp" PKG_LIBS="-lomp" "${R_HOME}/bin/R" CMD SHLIB test-omp.c >> config.log 2>&1; then
-      echo "yes"
-      export PKG_CFLAGS="${PKG_CFLAGS} -Xclang -fopenmp"
-      export PKG_LIBS="${PKG_LIBS} -lomp"
-      export R_OPENMP_ENABLED=1
-      return
-    else
-      echo "no"
-    fi
-
-    # https://github.com/Rdatatable/data.table/issues/6409
-    printf "%s" "* checking if R installation supports OpenMP with \"-fopenmp\" ... "
-    if CPPFLAGS="${CPPFLAGS} -fopenmp" "${R_HOME}/bin/R" CMD SHLIB test-omp.c >> config.log 2>&1; then
-      echo "yes"
-      export PKG_CFLAGS="${PKG_CFLAGS} -fopenmp"
-      export PKG_LIBS="${PKG_LIBS} -fopenmp"
-      export R_OPENMP_ENABLED=1
-      return
-    else
-      echo "no"
-    fi
+    test_openmp_variant "-Xclang -fopenmp" "-lomp" && return
 
     if [ "$(uname -m)" = "arm64" ]; then
       HOMEBREW_PREFIX=/opt/homebrew
     else
       HOMEBREW_PREFIX=/usr/local
     fi
-
-    if [ -e "${HOMEBREW_PREFIX}/opt/libomp" ]; then
-      printf "%s" "* checking if libomp installation at ${HOMEBREW_PREFIX}/opt/libomp can be used... "
-      LIBOMP_INCLUDE="-I${HOMEBREW_PREFIX}/opt/libomp/include -Xclang -fopenmp"
-      LIBOMP_LINK="-L${HOMEBREW_PREFIX}/opt/libomp/lib -lomp"
-      if ${CC} ${CFLAGS} ${LIBOMP_INCLUDE} ${LIBOMP_LINK} test-omp.c >> config.log 2>&1; then
-        echo "yes"
-        export PKG_CFLAGS="${PKG_CFLAGS} ${LIBOMP_INCLUDE}"
-        export PKG_LIBS="${PKG_LIBS} ${LIBOMP_LINK}"
-        export R_OPENMP_ENABLED=1
-        return
-      else
-        echo "no"
-      fi
+    test -e "${HOMEBREW_PREFIX}/opt/libomp" ] \
+    && test_openmp_variant \
+      "-I${HOMEBREW_PREFIX}/opt/libomp/include -Xclang -fopenmp" \
+      "-L${HOMEBREW_PREFIX}/opt/libomp/lib -lomp" \
+    && return
+
+    if "${CC}" --version | grep -q 'Apple clang 17'; then
+      test -e /usr/local/lib/libomp.dylib \
+      && test_openmp_variant "-Xclang -fopenmp" "/usr/local/lib/libomp.dylib" \
+      && return
+      echo "*** All OpenMP runtime tests failed and you're running Apple clang 17."
+      echo "*** Do you need a new OpenMP runtime from <https://mac.r-project.org/openmp/>?"
     fi
-
-  fi # uname=Darwin
+    ;;
+  esac
 
   # No support for OpenMP available
   export R_OPENMP_ENABLED=0
@@ -168,14 +157,10 @@ if [ "${R_OPENMP_ENABLED}" = "0" ]; then
   echo "***   https://github.com/Rdatatable/data.table/wiki/Installation"
   echo "*** Continuing installation without OpenMP support..."
   echo "***"
-  sed -e "s|@openmp_cflags@||" src/Makevars.in > src/Makevars
-else
-  sed -e "s|@openmp_cflags@|\$(SHLIB_OPENMP_CFLAGS)|" src/Makevars.in > src/Makevars
 fi
 
 # retain user supplied PKG_ env variables, #4664. See comments in Makevars.in too.
-sed -e "s|@PKG_CFLAGS@|$PKG_CFLAGS|" src/Makevars > src/Makevars.tmp && mv src/Makevars.tmp src/Makevars
-sed -e "s|@PKG_LIBS@|$PKG_LIBS|" src/Makevars > src/Makevars.tmp && mv src/Makevars.tmp src/Makevars
+sed -e "s|@PKG_CFLAGS@|$PKG_CFLAGS|" -e "s|@PKG_LIBS@|$PKG_LIBS|" src/Makevars.in > src/Makevars
 
 # optional dependency on zlib
 if [ "$NOZLIB" = "1" ]; then
diff --git a/src/Makevars.in b/src/Makevars.in
index fcfaceba9..0e90bfd6d 100644
--- a/src/Makevars.in
+++ b/src/Makevars.in
@@ -1,5 +1,5 @@
-PKG_CFLAGS = @PKG_CFLAGS@ @openmp_cflags@ @zlib_cflags@
-PKG_LIBS = @PKG_LIBS@ @openmp_cflags@ @zlib_libs@
+PKG_CFLAGS = @PKG_CFLAGS@ @zlib_cflags@
+PKG_LIBS = @PKG_LIBS@ @zlib_libs@
 # See WRE $1.2.1.1. But retain user supplied PKG_* too, #4664.
 # WRE states ($1.6) that += isn't portable and that we aren't allowed to use it.
 # Otherwise we could use the much simpler PKG_LIBS += @openmp_cflags@ -lz.

From 8ff74db857c4447e93fa99388b708962fa943bc6 Mon Sep 17 00:00:00 2001
From: Ivan K <krylov.r00t@gmail.com>
Date: Sat, 20 Sep 2025 11:35:20 +0300
Subject: [PATCH 08/17] GHA: rely on configure to pick up OpenMP runtime

Since the configure script specifically checks for clang 17 and
/usr/local/lib/libomp.dylib, don't set the environment variables in the
GitHub Actions configuration file. This way we'll know when it breaks.
---
 .github/workflows/R-CMD-check.yaml | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/.github/workflows/R-CMD-check.yaml b/.github/workflows/R-CMD-check.yaml
index 6d4b11159..91c80d33d 100644
--- a/.github/workflows/R-CMD-check.yaml
+++ b/.github/workflows/R-CMD-check.yaml
@@ -77,9 +77,6 @@ jobs:
             curl -O https://mac.r-project.org/openmp/openmp-19.1.0-darwin20-Release.tar.gz
             sudo tar fvvxz openmp-19.1.0-darwin20-Release.tar.gz -C /
             rm -f openmp-19.1.0-darwin20-Release.tar.gz
-            echo 'PKG_CFLAGS=-Xclang -fopenmp' >> $GITHUB_ENV
-            # Not the R-bundled -lomp, but our custom file installed just now
-            echo 'PKG_LIBS=/usr/local/lib/libomp.dylib' >> $GITHUB_ENV
           fi # otherwise R-bundled runtime is fine
 
       - name: Install dependencies

From c519473fa3f426c393a13fb39cc7af4430e6c555 Mon Sep 17 00:00:00 2001
From: Ivan K <krylov.r00t@gmail.com>
Date: Sat, 20 Sep 2025 12:00:50 +0300
Subject: [PATCH 09/17] NEWS item

---
 NEWS.md | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/NEWS.md b/NEWS.md
index 3110f0031..ddf5673e4 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -248,6 +248,8 @@
 
 19. New rolling functions, `frollmin` and `frollprod`, have been implemented, towards [#2778](https://github.com/Rdatatable/data.table/issues/2778). Thanks to @jangorecki for implementation.
 
+20. Enhanced tests for OpenMP support, detecting incompatibilities such as R-bundled runtime _vs._ newer Xcode and testing for a manually installed runtime from <https://mac.r-project.org/openmp>, [#6622](https://github.com/Rdatatable/data.table/issues/6622). Thanks to @dvg-p4 for initial report and testing, @twitched for the pointers, @tdhock and @aitap for the fix.
+
 ### BUG FIXES
 
 1. `fread()` no longer warns on certain systems on R 4.5.0+ where the file owner can't be resolved, [#6918](https://github.com/Rdatatable/data.table/issues/6918). Thanks @ProfFancyPants for the report and PR.

From 39beb9b0c102bc0325a6969b38622ce18f437437 Mon Sep 17 00:00:00 2001
From: Ivan K <krylov.r00t@gmail.com>
Date: Sat, 20 Sep 2025 12:15:38 +0300
Subject: [PATCH 10/17] Revert "rm fail-fast"

This reverts commit 354b8d3fe5479e5359579c33e0664764a4a2291f.
---
 .github/workflows/R-CMD-check.yaml | 1 +
 1 file changed, 1 insertion(+)

diff --git a/.github/workflows/R-CMD-check.yaml b/.github/workflows/R-CMD-check.yaml
index 91c80d33d..3c5ec9c85 100644
--- a/.github/workflows/R-CMD-check.yaml
+++ b/.github/workflows/R-CMD-check.yaml
@@ -15,6 +15,7 @@ jobs:
     name: ${{ matrix.config.os }} (${{ matrix.config.r }})
 
     strategy:
+      fail-fast: true
       matrix:
         config:
           # Rdatatable has full-strength GLCI which runs after merge. So we just need a few

From 020a89edb7f1526cbee4c3dfbcb206bdada45412 Mon Sep 17 00:00:00 2001
From: Ivan K <krylov.r00t@gmail.com>
Date: Sat, 20 Sep 2025 12:15:51 +0300
Subject: [PATCH 11/17] Revert "try removing concurrency"

This reverts commit eca2984a6fdae8ee204a2d9aac88631dcd490071.
---
 .github/workflows/R-CMD-check.yaml | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/.github/workflows/R-CMD-check.yaml b/.github/workflows/R-CMD-check.yaml
index 3c5ec9c85..de7d5e26f 100644
--- a/.github/workflows/R-CMD-check.yaml
+++ b/.github/workflows/R-CMD-check.yaml
@@ -8,6 +8,10 @@ on:
 
 name: R-CMD-check
 
+concurrency:
+  group: ${{ github.event.pull_request.number || github.run_id }}
+  cancel-in-progress: false
+
 jobs:
   R-CMD-check:
     runs-on: ${{ matrix.config.os }}

From ffc4417e0a61b7c13907f84f777c5aed4b6d8866 Mon Sep 17 00:00:00 2001
From: Ivan K <krylov.r00t@gmail.com>
Date: Sat, 20 Sep 2025 12:16:01 +0300
Subject: [PATCH 12/17] Revert "cancel in progress false for testing"

This reverts commit 82ad4a0b29bb1d15b07921c2c8e40eab7850e2d3.
---
 .github/workflows/R-CMD-check.yaml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/R-CMD-check.yaml b/.github/workflows/R-CMD-check.yaml
index de7d5e26f..6ef80db21 100644
--- a/.github/workflows/R-CMD-check.yaml
+++ b/.github/workflows/R-CMD-check.yaml
@@ -10,7 +10,7 @@ name: R-CMD-check
 
 concurrency:
   group: ${{ github.event.pull_request.number || github.run_id }}
-  cancel-in-progress: false
+  cancel-in-progress: true
 
 jobs:
   R-CMD-check:

From 3504c517dc14b3e9fec6b49a88e5cf0418945699 Mon Sep 17 00:00:00 2001
From: Ivan K <krylov.r00t@gmail.com>
Date: Sat, 20 Sep 2025 14:34:14 +0300
Subject: [PATCH 13/17] configure: stronger check for OpenMP

Also, check with no extra parameters first, like we used to.
---
 configure | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/configure b/configure
index 2acc77670..3892dc544 100755
--- a/configure
+++ b/configure
@@ -73,11 +73,12 @@ fi
 # Specifically use schedule(dynamic) to distinguish incompatibilities in OpenMP runtime on macOS, #7318
 
 cat <<EOF > test-omp.c
-#include <omp.h>
 void test_openmp(int * result) {
  int sum = 0;
+#ifdef _OPENMP
  #pragma omp parallel for reduction(+:sum) num_threads(2) schedule(dynamic)
  for (int i = 1; i <= 2; ++i) sum += i;
+#endif
  *result = sum;
 }
 EOF
@@ -110,8 +111,8 @@ stopifnot(identical(ans, 3L))
 
 detect_openmp () {
   # OpenMP flags provided in environment variables or specified when configuring R? Does -fopenmp work?
-  test_openmp_variant '$(SHLIB_OPENMP_CFLAGS)' '$(SHLIB_OPENMP_CFLAGS)' \
-  || test_openmp_variant "" "" \
+  test_openmp_variant "" "" \
+  || test_openmp_variant '$(SHLIB_OPENMP_CFLAGS)' '$(SHLIB_OPENMP_CFLAGS)' \
   || test_openmp_variant -fopenmp -fopenmp \
   && return
 

From 9e19ef4e858c8f8e68cc28ca3ef4d230685d2fbe Mon Sep 17 00:00:00 2001
From: aitap <krylov.r00t@gmail.com>
Date: Thu, 25 Sep 2025 20:50:00 +0000
Subject: [PATCH 14/17] Update .github/workflows/R-CMD-check.yaml

Co-authored-by: Toby Dylan Hocking <tdhock5@gmail.com>
---
 .github/workflows/R-CMD-check.yaml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/R-CMD-check.yaml b/.github/workflows/R-CMD-check.yaml
index 6ef80db21..99d534d64 100644
--- a/.github/workflows/R-CMD-check.yaml
+++ b/.github/workflows/R-CMD-check.yaml
@@ -26,7 +26,7 @@ jobs:
           # jobs (mainly test-coverage) to run on every commit in PRs so as to not slow down dev.
           # GHA does run these jobs concurrently but even so reducing the load seems like a good idea.
           - {os: windows-latest, r: 'devel'}
-          - {os: macos-14, r: 'release'}    
+          - {os: macos-15-intel, r: 'release'}    
           - {os: macos-15, r: 'release'}    
           # TODO(remotes>2.5.0): Use 24.04[noble?]
           - {os: ubuntu-22.04, r: 'release', rspm: "https://packagemanager.rstudio.com/cran/__linux__/jammy/latest"}

From d0f4b3050ebc8ce8acd3ec2da8f17e1761cddb15 Mon Sep 17 00:00:00 2001
From: aitap <krylov.r00t@gmail.com>
Date: Thu, 25 Sep 2025 20:50:49 +0000
Subject: [PATCH 15/17] Update .github/workflows/R-CMD-check.yaml

Co-authored-by: Toby Dylan Hocking <tdhock5@gmail.com>
---
 .github/workflows/R-CMD-check.yaml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/R-CMD-check.yaml b/.github/workflows/R-CMD-check.yaml
index 99d534d64..0039ee063 100644
--- a/.github/workflows/R-CMD-check.yaml
+++ b/.github/workflows/R-CMD-check.yaml
@@ -75,7 +75,7 @@ jobs:
         with:
           type: 'minimal'
 
-      - name: Intall and configure OpenMP runtime
+      - name: Install and configure OpenMP runtime
         if: runner.os == 'macOS'
         run: |
           if clang --version | grep 'clang version 17'; then

From 8a144cdad8df87cd5dc63201dfae1d0e73f14d67 Mon Sep 17 00:00:00 2001
From: Ivan K <krylov.r00t@gmail.com>
Date: Fri, 26 Sep 2025 00:05:49 +0300
Subject: [PATCH 16/17] GHA: cache by runner architecture in addition to OS

---
 .github/workflows/R-CMD-check.yaml | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/R-CMD-check.yaml b/.github/workflows/R-CMD-check.yaml
index 0039ee063..37ee06451 100644
--- a/.github/workflows/R-CMD-check.yaml
+++ b/.github/workflows/R-CMD-check.yaml
@@ -58,8 +58,8 @@ jobs:
         uses: actions/cache@v4
         with:
           path: ${{ env.R_LIBS_USER }}
-          key: ${{ runner.os }}-${{ hashFiles('.github/R-version') }}-1-${{ hashFiles('.github/depends.Rds') }}
-          restore-keys: ${{ runner.os }}-${{ hashFiles('.github/R-version') }}-1-
+          key: ${{ runner.os }}-${{ runner.arch }}-${{ hashFiles('.github/R-version') }}-1-${{ hashFiles('.github/depends.Rds') }}
+          restore-keys: ${{ runner.os }}-${{ runner.arch }}-${{ hashFiles('.github/R-version') }}-1-
 
       - name: Install system dependencies
         if: runner.os == 'Linux'

From 5bd55056e1e3cb833830c112ac191239fab8f9fe Mon Sep 17 00:00:00 2001
From: Ivan K <krylov.r00t@gmail.com>
Date: Fri, 3 Oct 2025 18:07:38 +0300
Subject: [PATCH 17/17] Move the NEWS item to NOTES

---
 NEWS.md | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/NEWS.md b/NEWS.md
index ddf5673e4..b87b1e7d6 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -248,8 +248,6 @@
 
 19. New rolling functions, `frollmin` and `frollprod`, have been implemented, towards [#2778](https://github.com/Rdatatable/data.table/issues/2778). Thanks to @jangorecki for implementation.
 
-20. Enhanced tests for OpenMP support, detecting incompatibilities such as R-bundled runtime _vs._ newer Xcode and testing for a manually installed runtime from <https://mac.r-project.org/openmp>, [#6622](https://github.com/Rdatatable/data.table/issues/6622). Thanks to @dvg-p4 for initial report and testing, @twitched for the pointers, @tdhock and @aitap for the fix.
-
 ### BUG FIXES
 
 1. `fread()` no longer warns on certain systems on R 4.5.0+ where the file owner can't be resolved, [#6918](https://github.com/Rdatatable/data.table/issues/6918). Thanks @ProfFancyPants for the report and PR.
@@ -313,6 +311,8 @@
 
 6. Using a double vector in `set()`'s `i=` and/or `j=` no longer throws a warning about preferring integer, [#6594](https://github.com/Rdatatable/data.table/issues/6594). While it may improve efficiency to use integer, there's no guarantee it's an improvement and the difference is likely to be minimal. The coercion will still be reported under `datatable.verbose=TRUE`. For package/production use cases, static analyzers such as `lintr::implicit_integer_linter()` can also report when numeric literals should be rewritten as integer literals.
 
+7. Enhanced tests for OpenMP support, detecting incompatibilities such as R-bundled runtime _vs._ newer Xcode and testing for a manually installed runtime from <https://mac.r-project.org/openmp>, [#6622](https://github.com/Rdatatable/data.table/issues/6622). Thanks to @dvg-p4 for initial report and testing, @twitched for the pointers, @tdhock and @aitap for the fix.
+
 ## data.table [v1.17.8](https://github.com/Rdatatable/data.table/milestone/41) (6 July 2025)
 
 1. Internal functions used to signal errors are now marked as non-returning, silencing a compiler warning about potentially unchecked allocation failure. Thanks to Prof. Brian D. Ripley for the report and @aitap for the fix, [#7070](https://github.com/Rdatatable/data.table/pull/7070).