From ad1535e9173f1c013b5287852d7ef0e4f00fabd1 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Thu, 23 Jul 2026 11:30:16 +0000
Subject: [PATCH 1/3] Initial plan


From a8fb692042e4b55a3c337c7f43131f2d65ade9fc Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Thu, 23 Jul 2026 11:32:12 +0000
Subject: [PATCH 2/3] fix: set JAVA_HOME on Windows in setup-r-dependencies

---
 setup-r-dependencies/README.md   |  4 ++++
 setup-r-dependencies/action.yaml | 12 ++++++++++++
 2 files changed, 16 insertions(+)

diff --git a/setup-r-dependencies/README.md b/setup-r-dependencies/README.md
index 8705132c..aac91a7f 100644
--- a/setup-r-dependencies/README.md
+++ b/setup-r-dependencies/README.md
@@ -286,6 +286,10 @@ On macOS you can usually use `brew`, here is an example step in a workflow:
 On Windows you can usually use `pacman` that is included in Rtools4, or
 `choco` to install external software:
 
+`setup-r-dependencies` also sets `JAVA_HOME` to Java 21 on GitHub-hosted
+Windows runners (`JAVA_HOME_21_X64` on x64, `JAVA_HOME_21_AARCH64` on arm64)
+if `JAVA_HOME` is not already set.
+
 ```yaml
       - name: Install most Windows system dependencies
         if: runner.os == 'Windows'
diff --git a/setup-r-dependencies/action.yaml b/setup-r-dependencies/action.yaml
index e7082ba1..282519d1 100644
--- a/setup-r-dependencies/action.yaml
+++ b/setup-r-dependencies/action.yaml
@@ -128,6 +128,18 @@ runs:
           cat("::endgroup::\n")
         shell: Rscript {0}
 
+      - name: Set JAVA_HOME (Windows x64)
+        if: ${{ runner.os == 'Windows' && runner.arch == 'X64' && env.JAVA_HOME == '' }}
+        shell: bash
+        run: |
+          echo "JAVA_HOME=${JAVA_HOME_21_X64}" >> $GITHUB_ENV
+
+      - name: Set JAVA_HOME (Windows arm64)
+        if: ${{ runner.os == 'Windows' && runner.arch == 'ARM64' && env.JAVA_HOME == '' }}
+        shell: bash
+        run: |
+          echo "JAVA_HOME=${JAVA_HOME_21_AARCH64}" >> $GITHUB_ENV
+
       - name: Install pak (Unix)
         if: ${{ runner.os != 'Windows' && inputs.pak-version != 'none' }}
         run: |

From d27332520b83287737d06ade93acf4785cadff87 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Thu, 23 Jul 2026 11:35:23 +0000
Subject: [PATCH 3/3] docs: clarify JAVA_HOME setup note placement

---
 setup-r-dependencies/README.md   |  8 ++++----
 setup-r-dependencies/action.yaml | 20 +++++++++++---------
 2 files changed, 15 insertions(+), 13 deletions(-)

diff --git a/setup-r-dependencies/README.md b/setup-r-dependencies/README.md
index aac91a7f..e361a3c4 100644
--- a/setup-r-dependencies/README.md
+++ b/setup-r-dependencies/README.md
@@ -286,10 +286,6 @@ On macOS you can usually use `brew`, here is an example step in a workflow:
 On Windows you can usually use `pacman` that is included in Rtools4, or
 `choco` to install external software:
 
-`setup-r-dependencies` also sets `JAVA_HOME` to Java 21 on GitHub-hosted
-Windows runners (`JAVA_HOME_21_X64` on x64, `JAVA_HOME_21_AARCH64` on arm64)
-if `JAVA_HOME` is not already set.
-
 ```yaml
       - name: Install most Windows system dependencies
         if: runner.os == 'Windows'
@@ -305,6 +301,10 @@ if `JAVA_HOME` is not already set.
           choco install mariadb
 ```
 
+`setup-r-dependencies` also sets `JAVA_HOME` to Java 21 on GitHub-hosted
+Windows runners (`JAVA_HOME_21_X64` on x64, `JAVA_HOME_21_AARCH64` on arm64)
+if `JAVA_HOME` is not already set.
+
 # Installing the latest dependencies
 
 Note that `setup-r-dependencies` does _not_ necessarily install the latest
diff --git a/setup-r-dependencies/action.yaml b/setup-r-dependencies/action.yaml
index 282519d1..bb19e3ef 100644
--- a/setup-r-dependencies/action.yaml
+++ b/setup-r-dependencies/action.yaml
@@ -128,17 +128,19 @@ runs:
           cat("::endgroup::\n")
         shell: Rscript {0}
 
-      - name: Set JAVA_HOME (Windows x64)
-        if: ${{ runner.os == 'Windows' && runner.arch == 'X64' && env.JAVA_HOME == '' }}
+      - name: Set JAVA_HOME (Windows)
+        if: ${{ runner.os == 'Windows' }}
         shell: bash
         run: |
-          echo "JAVA_HOME=${JAVA_HOME_21_X64}" >> $GITHUB_ENV
-
-      - name: Set JAVA_HOME (Windows arm64)
-        if: ${{ runner.os == 'Windows' && runner.arch == 'ARM64' && env.JAVA_HOME == '' }}
-        shell: bash
-        run: |
-          echo "JAVA_HOME=${JAVA_HOME_21_AARCH64}" >> $GITHUB_ENV
+          if [ -z "${JAVA_HOME:-}" ]; then
+            arch="${RUNNER_ARCH^^}"
+            case "${arch}" in
+              X64) echo "JAVA_HOME=${JAVA_HOME_21_X64}" >> $GITHUB_ENV ;;
+              # GitHub runners expose ARM64 Java 21 in JAVA_HOME_21_AARCH64.
+              ARM64) echo "JAVA_HOME=${JAVA_HOME_21_AARCH64}" >> $GITHUB_ENV ;;
+              *) echo "Warning: unsupported Windows architecture '${arch}', JAVA_HOME not set by setup-r-dependencies." >&2 ;;
+            esac
+          fi
 
       - name: Install pak (Unix)
         if: ${{ runner.os != 'Windows' && inputs.pak-version != 'none' }}