From 86627cc70fb3e9fe3b9fe8c33df0cc840e1ed8e2 Mon Sep 17 00:00:00 2001
From: maximebuyse <45398004+maximebuyse@users.noreply.github.com>
Date: Tue, 20 Jan 2026 17:03:47 +0100
Subject: [PATCH 1/4] Update action.yml

---
 action.yml | 39 ++++++++++++++++++++++++++++++++++++++-
 1 file changed, 38 insertions(+), 1 deletion(-)

diff --git a/action.yml b/action.yml
index b1ff22f..d95ff10 100644
--- a/action.yml
+++ b/action.yml
@@ -21,8 +21,45 @@ runs:
       with:
         use-flakehub: false
 
-    - name: Install F*
+    - name: Try to install prebuilt F* binary    
       if: inputs.fstar != ''
+      id: binary-install
+      shell: bash
+      run: |
+        VERSION="${{ inputs.version }}"
+        OS_NAME=$(uname -s)
+        ARCH=$(uname -m)
+        
+        # Map OS and Architecture to the URL format
+        if [ "$OS_NAME" = "Darwin" ]; then
+          PLATFORM="Darwin-arm64"
+        elif [ "$OS_NAME" = "Linux" ] && [ "$ARCH" = "x86_64" ]; then
+          PLATFORM="Linux-x86_64"
+        else
+          echo "Unsupported platform for binary; falling back to Nix."
+          echo "installed=false" >> $GITHUB_OUTPUT
+          exit 0
+        fi
+
+        URL="https://github.com/FStarLang/FStar/releases/download/$VERSION/fstar-$VERSION-$PLATFORM.tar.gz"
+        
+        # Check if the URL exists using a HEAD request
+        if curl --output /dev/null --silent --head --fail "$URL"; then
+          echo "Downloading $URL..."
+          curl -L "$URL" -o fstar.tar.gz
+          mkdir -p $HOME/.fstar
+          tar -xzf fstar.tar.gz -C $HOME/.fstar --strip-components=1
+          
+          # Add the bin directory to the GitHub PATH
+          echo "$HOME/.fstar/bin" >> $GITHUB_PATH
+          echo "installed=true" >> $GITHUB_OUTPUT
+        else
+          echo "Prebuilt binary not found at $URL; falling back to Nix."
+          echo "installed=false" >> $GITHUB_OUTPUT
+        fi
+
+    - name: Install F*
+      if: inputs.fstar != '' && steps.binary-install.outputs.installed == 'false'
       shell: bash
       run: nix profile install "$FLAKE"
       env:

From a1a81507da283a056c253c0e471997526732fbf0 Mon Sep 17 00:00:00 2001
From: maximebuyse <45398004+maximebuyse@users.noreply.github.com>
Date: Tue, 20 Jan 2026 17:16:08 +0100
Subject: [PATCH 2/4] Inject F* version as env var

---
 action.yml | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/action.yml b/action.yml
index d95ff10..b626091 100644
--- a/action.yml
+++ b/action.yml
@@ -25,8 +25,9 @@ runs:
       if: inputs.fstar != ''
       id: binary-install
       shell: bash
+      env: 
+        VERSION: "${{ inputs.version }}"
       run: |
-        VERSION="${{ inputs.version }}"
         OS_NAME=$(uname -s)
         ARCH=$(uname -m)
         

From 06013d8a60610fcc3fb453065191387b890b142c Mon Sep 17 00:00:00 2001
From: maximebuyse <45398004+maximebuyse@users.noreply.github.com>
Date: Tue, 20 Jan 2026 17:18:05 +0100
Subject: [PATCH 3/4] Correct input for F* version.

---
 action.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/action.yml b/action.yml
index b626091..6941a42 100644
--- a/action.yml
+++ b/action.yml
@@ -26,7 +26,7 @@ runs:
       id: binary-install
       shell: bash
       env: 
-        VERSION: "${{ inputs.version }}"
+        VERSION: "${{ inputs.fstar }}"
       run: |
         OS_NAME=$(uname -s)
         ARCH=$(uname -m)

From 6c734302f9a0434cf590e0ba18c9dd9b28fc6659 Mon Sep 17 00:00:00 2001
From: Maxime Buyse <maxime@cryspen.com>
Date: Wed, 21 Jan 2026 10:02:07 +0100
Subject: [PATCH 4/4] Fix number of directories to strip.

---
 action.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/action.yml b/action.yml
index 6941a42..5743d94 100644
--- a/action.yml
+++ b/action.yml
@@ -49,7 +49,7 @@ runs:
           echo "Downloading $URL..."
           curl -L "$URL" -o fstar.tar.gz
           mkdir -p $HOME/.fstar
-          tar -xzf fstar.tar.gz -C $HOME/.fstar --strip-components=1
+          tar -xzf fstar.tar.gz -C $HOME/.fstar --strip-components=2
           
           # Add the bin directory to the GitHub PATH
           echo "$HOME/.fstar/bin" >> $GITHUB_PATH