From 1be5ab857a0a0866373cbaf82864c570dce9a6b3 Mon Sep 17 00:00:00 2001
From: Bryce Mecum <petridish@gmail.com>
Date: Sun, 17 May 2026 08:08:11 -0700
Subject: [PATCH 1/5] Set up Emscripten and R-Universe build

---
 dev/tasks/r/github.linux.r-universe.wasm.yml | 75 ++++++++++++++++++++
 dev/tasks/tasks.yml                          |  4 ++
 r/inst/build_arrow_static.sh                 | 39 +++++++++-
 3 files changed, 116 insertions(+), 2 deletions(-)
 create mode 100644 dev/tasks/r/github.linux.r-universe.wasm.yml

diff --git a/dev/tasks/r/github.linux.r-universe.wasm.yml b/dev/tasks/r/github.linux.r-universe.wasm.yml
new file mode 100644
index 000000000000..ee38740bb47d
--- /dev/null
+++ b/dev/tasks/r/github.linux.r-universe.wasm.yml
@@ -0,0 +1,75 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+{% import 'macros.jinja' as macros with context %}
+
+{{ macros.github_header() }}
+
+jobs:
+  r-universe-wasm:
+    name: "R-universe Wasm build"
+    runs-on: ubuntu-latest
+    timeout-minutes: 60
+
+    steps:
+      {{ macros.github_checkout_arrow()|indent }}
+
+      - uses: r-lib/actions/setup-r@v2
+        with:
+          install-r: true
+
+      - name: Build Arrow R source package
+        shell: bash
+        run: |
+          cd arrow/r
+          make sync-cpp
+          R CMD build --no-build-vignettes .
+
+      - name: Pull the R-universe Wasm image
+        shell: bash
+        run: docker pull ghcr.io/r-universe-org/build-wasm:latest
+
+      - name: Build Wasm binary in the R-universe container
+        shell: bash
+        run: |
+          docker run --rm \
+            -v "${PWD}/arrow/r:/work" \
+            -w /work \
+            ghcr.io/r-universe-org/build-wasm:latest \
+            bash -lc '
+              set -euxo pipefail
+              R -q -e "if (!requireNamespace(\"pak\", quietly = TRUE)) install.packages(\"pak\", repos = \"https://cloud.r-project.org\"); if (!requireNamespace(\"rwasm\", quietly = TRUE)) pak::pak(\"r-wasm/rwasm\"); rwasm::build(\".\")" \
+                2>&1 | tee build-wasm.log
+            '
+
+      - name: List generated artifacts
+        if: always()
+        shell: bash
+        run: |
+          ls -lh arrow/r/arrow_*.tar.gz
+          ls -lh arrow/r/arrow_*.tgz || true
+          ls -lh arrow/r/build-wasm.log || true
+
+      - name: Upload Wasm build artifacts
+        if: always()
+        uses: actions/upload-artifact@v4
+        with:
+          name: r-wasm-build
+          path: |
+            arrow/r/arrow_*.tar.gz
+            arrow/r/arrow_*.tgz
+            arrow/r/build-wasm.log
diff --git a/dev/tasks/tasks.yml b/dev/tasks/tasks.yml
index 9647e5531da3..4b46fad3f0df 100644
--- a/dev/tasks/tasks.yml
+++ b/dev/tasks/tasks.yml
@@ -651,6 +651,10 @@ tasks:
       env:
         CMAKE_BUILD_TYPE: MinSizeRel
 
+  test-r-r-universe-wasm:
+    ci: github
+    template: r/github.linux.r-universe.wasm.yml
+
   test-r-devdocs:
     ci: github
     template: r/github.devdocs.yml
diff --git a/r/inst/build_arrow_static.sh b/r/inst/build_arrow_static.sh
index 241994223d3e..2e49051f469f 100755
--- a/r/inst/build_arrow_static.sh
+++ b/r/inst/build_arrow_static.sh
@@ -36,7 +36,7 @@ set -x
 SOURCE_DIR="$(cd "${SOURCE_DIR}" && pwd)"
 DEST_DIR="$(mkdir -p "${DEST_DIR}" && cd "${DEST_DIR}" && pwd)"
 
-if [ "$N_JOBS" = "" ]; then
+if ! [[ "${N_JOBS:-}" =~ ^[1-9][0-9]*$ ]]; then
   if [ "`uname -s`" = "Darwin" ]; then
     N_JOBS="$(sysctl -n hw.logicalcpu)"
   else
@@ -62,9 +62,39 @@ case "$CXX" in
     ;;
 esac
 
+# When building the R package for webR/rwasm, the R toolchain points CC/CXX to
+# emcc/em++, but CMake still needs to be invoked via emcmake so it configures
+# Arrow for Emscripten instead of treating the target as a generic wasm32 host.
+ARROW_WASM_BUILD="OFF"
+CMAKE_WRAPPER=""
+case "${CC} ${CXX}" in
+  *emcc*|*em++*)
+    ARROW_WASM_BUILD="ON"
+    CMAKE_WRAPPER="emcmake"
+    ARROW_DEPENDENCY_SOURCE="BUNDLED"
+    ARROW_DEPENDENCY_USE_SHARED="OFF"
+    ARROW_ENABLE_THREADING="OFF"
+    ARROW_GCS="OFF"
+    ARROW_JEMALLOC="OFF"
+    ARROW_MIMALLOC="OFF"
+    ARROW_RUNTIME_SIMD_LEVEL="NONE"
+    ARROW_S3="OFF"
+    ARROW_SIMD_LEVEL="NONE"
+    ARROW_WITH_BROTLI="OFF"
+    ARROW_WITH_BZ2="OFF"
+    ARROW_WITH_ZSTD="OFF"
+    N_JOBS=2
+    ;;
+esac
+
+if [ "${ARROW_WASM_BUILD}" = "ON" ] && ! command -v emcmake >/dev/null 2>&1; then
+  echo "emcmake is required for Emscripten/webR builds but was not found in PATH"
+  exit 1
+fi
+
 mkdir -p "${BUILD_DIR}"
 pushd "${BUILD_DIR}"
-${CMAKE} -DARROW_BOOST_USE_SHARED=OFF \
+${CMAKE_WRAPPER} ${CMAKE} -DARROW_BOOST_USE_SHARED=OFF \
     -DARROW_SNAPPY_USE_SHARED=OFF \
     -DARROW_BUILD_TESTS=OFF \
     -DARROW_BUILD_SHARED=OFF \
@@ -74,6 +104,9 @@ ${CMAKE} -DARROW_BOOST_USE_SHARED=OFF \
     -DARROW_CSV=ON \
     -DARROW_DATASET=${ARROW_DATASET:-ON} \
     -DARROW_DEPENDENCY_SOURCE=${ARROW_DEPENDENCY_SOURCE:-AUTO} \
+    -DARROW_DEPENDENCY_USE_SHARED=${ARROW_DEPENDENCY_USE_SHARED:-ON} \
+    -DARROW_ENABLE_THREADING=${ARROW_ENABLE_THREADING:-ON} \
+    -DARROW_FLIGHT=${ARROW_FLIGHT:-OFF} \
     -DAWSSDK_SOURCE=${AWSSDK_SOURCE:-} \
     -DBoost_SOURCE=${Boost_SOURCE:-} \
     -Dlz4_SOURCE=${lz4_SOURCE:-} \
@@ -84,6 +117,8 @@ ${CMAKE} -DARROW_BOOST_USE_SHARED=OFF \
     -DARROW_JSON=${ARROW_JSON:-ON} \
     -DARROW_PARQUET=${ARROW_PARQUET:-ON} \
     -DARROW_S3=${ARROW_S3:-$ARROW_DEFAULT_PARAM} \
+    -DARROW_RUNTIME_SIMD_LEVEL=${ARROW_RUNTIME_SIMD_LEVEL:-MAX} \
+    -DARROW_SIMD_LEVEL=${ARROW_SIMD_LEVEL:-DEFAULT} \
     -DARROW_WITH_BROTLI=${ARROW_WITH_BROTLI:-$ARROW_DEFAULT_PARAM} \
     -DARROW_WITH_BZ2=${ARROW_WITH_BZ2:-$ARROW_DEFAULT_PARAM} \
     -DARROW_WITH_LZ4=${ARROW_WITH_LZ4:-ON} \

From 5ee845735ebc70610d2597e41917a59895b4b148 Mon Sep 17 00:00:00 2001
From: Bryce Mecum <petridish@gmail.com>
Date: Mon, 18 May 2026 01:08:18 +0000
Subject: [PATCH 2/5] clean up

---
 r/inst/build_arrow_static.sh | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/r/inst/build_arrow_static.sh b/r/inst/build_arrow_static.sh
index 2e49051f469f..8cd209758471 100755
--- a/r/inst/build_arrow_static.sh
+++ b/r/inst/build_arrow_static.sh
@@ -36,7 +36,7 @@ set -x
 SOURCE_DIR="$(cd "${SOURCE_DIR}" && pwd)"
 DEST_DIR="$(mkdir -p "${DEST_DIR}" && cd "${DEST_DIR}" && pwd)"
 
-if ! [[ "${N_JOBS:-}" =~ ^[1-9][0-9]*$ ]]; then
+if [ "$N_JOBS" = "" ]; then
   if [ "`uname -s`" = "Darwin" ]; then
     N_JOBS="$(sysctl -n hw.logicalcpu)"
   else
@@ -62,9 +62,7 @@ case "$CXX" in
     ;;
 esac
 
-# When building the R package for webR/rwasm, the R toolchain points CC/CXX to
-# emcc/em++, but CMake still needs to be invoked via emcmake so it configures
-# Arrow for Emscripten instead of treating the target as a generic wasm32 host.
+# Detect and handle Emscripten build for R-Universe
 ARROW_WASM_BUILD="OFF"
 CMAKE_WRAPPER=""
 case "${CC} ${CXX}" in

From b37e9d027dd2ccb65acb6f84f63c534c30872d26 Mon Sep 17 00:00:00 2001
From: Bryce Mecum <petridish@gmail.com>
Date: Mon, 18 May 2026 04:14:02 +0000
Subject: [PATCH 3/5] Move cmake stuff into nixlibs

---
 r/inst/build_arrow_static.sh | 31 ++-----------------------------
 r/tools/nixlibs.R            | 35 +++++++++++++++++++++++++++++++++++
 2 files changed, 37 insertions(+), 29 deletions(-)

diff --git a/r/inst/build_arrow_static.sh b/r/inst/build_arrow_static.sh
index 8cd209758471..121211fb01fa 100755
--- a/r/inst/build_arrow_static.sh
+++ b/r/inst/build_arrow_static.sh
@@ -62,33 +62,8 @@ case "$CXX" in
     ;;
 esac
 
-# Detect and handle Emscripten build for R-Universe
-ARROW_WASM_BUILD="OFF"
-CMAKE_WRAPPER=""
-case "${CC} ${CXX}" in
-  *emcc*|*em++*)
-    ARROW_WASM_BUILD="ON"
-    CMAKE_WRAPPER="emcmake"
-    ARROW_DEPENDENCY_SOURCE="BUNDLED"
-    ARROW_DEPENDENCY_USE_SHARED="OFF"
-    ARROW_ENABLE_THREADING="OFF"
-    ARROW_GCS="OFF"
-    ARROW_JEMALLOC="OFF"
-    ARROW_MIMALLOC="OFF"
-    ARROW_RUNTIME_SIMD_LEVEL="NONE"
-    ARROW_S3="OFF"
-    ARROW_SIMD_LEVEL="NONE"
-    ARROW_WITH_BROTLI="OFF"
-    ARROW_WITH_BZ2="OFF"
-    ARROW_WITH_ZSTD="OFF"
-    N_JOBS=2
-    ;;
-esac
-
-if [ "${ARROW_WASM_BUILD}" = "ON" ] && ! command -v emcmake >/dev/null 2>&1; then
-  echo "emcmake is required for Emscripten/webR builds but was not found in PATH"
-  exit 1
-fi
+# Used for Emscripten
+: ${CMAKE_WRAPPER:=""}
 
 mkdir -p "${BUILD_DIR}"
 pushd "${BUILD_DIR}"
@@ -115,8 +90,6 @@ ${CMAKE_WRAPPER} ${CMAKE} -DARROW_BOOST_USE_SHARED=OFF \
     -DARROW_JSON=${ARROW_JSON:-ON} \
     -DARROW_PARQUET=${ARROW_PARQUET:-ON} \
     -DARROW_S3=${ARROW_S3:-$ARROW_DEFAULT_PARAM} \
-    -DARROW_RUNTIME_SIMD_LEVEL=${ARROW_RUNTIME_SIMD_LEVEL:-MAX} \
-    -DARROW_SIMD_LEVEL=${ARROW_SIMD_LEVEL:-DEFAULT} \
     -DARROW_WITH_BROTLI=${ARROW_WITH_BROTLI:-$ARROW_DEFAULT_PARAM} \
     -DARROW_WITH_BZ2=${ARROW_WITH_BZ2:-$ARROW_DEFAULT_PARAM} \
     -DARROW_WITH_LZ4=${ARROW_WITH_LZ4:-ON} \
diff --git a/r/tools/nixlibs.R b/r/tools/nixlibs.R
index 947bb6c3f5cc..ba705e03ad7e 100644
--- a/r/tools/nixlibs.R
+++ b/r/tools/nixlibs.R
@@ -616,6 +616,7 @@ build_libarrow <- function(src_dir, dst_dir) {
   }
 
   env_var_list <- with_cloud_support(env_var_list)
+  env_var_list <- with_wasm_support(env_var_list)
 
   # turn_off_all_optional_features() needs to happen after
   # with_cloud_support(), since it might turn features ON.
@@ -883,6 +884,40 @@ is_feature_requested <- function(env_varname, env_var_list, default = env_is("LI
   requested
 }
 
+with_wasm_support <- function(env_var_list) {
+  cc <- env_var_list[["CC"]]
+  cxx <- env_var_list[["CXX"]]
+  if (!grepl("emcc", cc) && !grepl("em\\+\\+", cxx)) {
+    return(env_var_list)
+  }
+
+  lg("Emscripten compiler detected; configuring for WASM build", .indent = "****")
+
+  if (!nzchar(Sys.which("emcmake"))) {
+    stop("emcmake is required for Emscripten/webR builds but was not found in PATH")
+  }
+
+  wasm_overrides <- c(
+    CMAKE_WRAPPER = "emcmake",
+    ARROW_DEPENDENCY_SOURCE = "BUNDLED",
+    ARROW_DEPENDENCY_USE_SHARED = "OFF",
+    ARROW_ENABLE_THREADING = "OFF",
+    ARROW_GCS = "OFF",
+    ARROW_JEMALLOC = "OFF",
+    ARROW_MIMALLOC = "OFF",
+    ARROW_S3 = "OFF",
+    ARROW_WITH_BROTLI = "OFF",
+    ARROW_WITH_BZ2 = "OFF",
+    ARROW_WITH_ZSTD = "OFF",
+    N_JOBS = "2",
+    EXTRA_CMAKE_FLAGS = paste(
+      env_var_list[["EXTRA_CMAKE_FLAGS"]],
+      "-DARROW_SIMD_LEVEL=NONE -DARROW_RUNTIME_SIMD_LEVEL=NONE"
+    )
+  )
+  replace(env_var_list, names(wasm_overrides), wasm_overrides)
+}
+
 with_cloud_support <- function(env_var_list) {
   arrow_s3 <- is_feature_requested("ARROW_S3", env_var_list)
   arrow_gcs <- is_feature_requested("ARROW_GCS", env_var_list)

From 48ffd7eee21e31eae11f812573e008e35beac976 Mon Sep 17 00:00:00 2001
From: Bryce Mecum <petridish@gmail.com>
Date: Tue, 19 May 2026 09:25:27 -0700
Subject: [PATCH 4/5] rename task

---
 ...thub.linux.r-universe.wasm.yml => github.linux.r-wasm.yml} | 0
 dev/tasks/tasks.yml                                           | 4 ++--
 2 files changed, 2 insertions(+), 2 deletions(-)
 rename dev/tasks/r/{github.linux.r-universe.wasm.yml => github.linux.r-wasm.yml} (100%)

diff --git a/dev/tasks/r/github.linux.r-universe.wasm.yml b/dev/tasks/r/github.linux.r-wasm.yml
similarity index 100%
rename from dev/tasks/r/github.linux.r-universe.wasm.yml
rename to dev/tasks/r/github.linux.r-wasm.yml
diff --git a/dev/tasks/tasks.yml b/dev/tasks/tasks.yml
index 4b46fad3f0df..2d2b9ae39e41 100644
--- a/dev/tasks/tasks.yml
+++ b/dev/tasks/tasks.yml
@@ -651,9 +651,9 @@ tasks:
       env:
         CMAKE_BUILD_TYPE: MinSizeRel
 
-  test-r-r-universe-wasm:
+  test-r-wasm:
     ci: github
-    template: r/github.linux.r-universe.wasm.yml
+    template: r/github.linux.r-wasm.yml
 
   test-r-devdocs:
     ci: github

From 7eb72ac2d1927411ddbe9ce5bd328691ce142437 Mon Sep 17 00:00:00 2001
From: Bryce Mecum <petridish@gmail.com>
Date: Tue, 19 May 2026 09:26:42 -0700
Subject: [PATCH 5/5] remove flight line

---
 r/inst/build_arrow_static.sh | 1 -
 1 file changed, 1 deletion(-)

diff --git a/r/inst/build_arrow_static.sh b/r/inst/build_arrow_static.sh
index 121211fb01fa..349531b75fd9 100755
--- a/r/inst/build_arrow_static.sh
+++ b/r/inst/build_arrow_static.sh
@@ -79,7 +79,6 @@ ${CMAKE_WRAPPER} ${CMAKE} -DARROW_BOOST_USE_SHARED=OFF \
     -DARROW_DEPENDENCY_SOURCE=${ARROW_DEPENDENCY_SOURCE:-AUTO} \
     -DARROW_DEPENDENCY_USE_SHARED=${ARROW_DEPENDENCY_USE_SHARED:-ON} \
     -DARROW_ENABLE_THREADING=${ARROW_ENABLE_THREADING:-ON} \
-    -DARROW_FLIGHT=${ARROW_FLIGHT:-OFF} \
     -DAWSSDK_SOURCE=${AWSSDK_SOURCE:-} \
     -DBoost_SOURCE=${Boost_SOURCE:-} \
     -Dlz4_SOURCE=${lz4_SOURCE:-} \