feat: add a custom node script that adds codspeed v8 flags

.gitattributes

@@ -1 +1,2 @@
-dist/** -diff linguist-generated=true 
+dist/** -diff linguist-generated=true
+dist/bin/node -diff linguist-generated=false

dist/bin/node

@@ -0,0 +1,48 @@
+#!/bin/bash
+set -eo pipefail
+
+# Custom script to replace node and run with V8 flags that make the execution of the
+# benchmarks more predictable.
+# Depending on the version of node, some flags may be deprecated.
+
+# Retrieve the original path by removing the folder containing CodSpeedHQ/action from the path.
+ORIGINAL_PATH=$(echo "$PATH" | tr ":" "\n" | grep -v "CodSpeedHQ/action" | tr "\n" ":")
+# Check if node is in the original path.
+if ! env PATH="$ORIGINAL_PATH" which node &>/dev/null; then
+    echo "Error: node not found in PATH. There might be a problem with the node installation."
+    exit 1
+fi
+# Save the real node path.
+REAL_NODE_PATH=$(env PATH="$ORIGINAL_PATH" which node)
+
+V8_FLAGS=(
+    "--hash-seed=1"
+    "--random-seed=1"
+    "--no-opt"
+    "--predictable"
+    "--predictable-gc-schedule"
+)
+
+# get node major version, using bash regex
+NODE_MAJOR_VERSION=$($REAL_NODE_PATH --version | sed -E 's/^v([0-9]+)\..*$/\1/')
+
+# add flags deprecated in node 18 in older versions
+if [ "$NODE_MAJOR_VERSION" -lt 18 ]; then
+    V8_FLAGS=(
+        "${V8_FLAGS[@]}"
+        "--no-randomize-hashes"
+    )
+fi
+# add flags deprecated in node 20 in older versions
+if [ "$NODE_MAJOR_VERSION" -lt 20 ]; then
+    V8_FLAGS=(
+        "${V8_FLAGS[@]}"
+        "--no-scavenge-task"
+    )
+fi
+
+echo "::debug::Running the CodSpeed node script, the node command that will be run:"
+echo "::debug::$REAL_NODE_PATH" "${V8_FLAGS[@]}" "$@"
+
+# Call the real "node" command with any arguments passed to this script.
+$REAL_NODE_PATH "${V8_FLAGS[@]}" "$@"

src/run.ts

@@ -71,6 +71,9 @@ const run = async (inputs: ActionInputs): Promise<{profileFolder: string}> => {
   // Fixes a compatibility issue with cargo 1.66+ running directly under valgrind <3.20
   const benchCommand = inputs.run.replace("cargo codspeed", "cargo-codspeed");
 
+  const customBinPath = `${__dirname}/bin`;
+  core.debug(`custom bin path: ${customBinPath}`);
+
   try {
     await exec(
       [
@@ -85,17 +88,10 @@ const run = async (inputs: ActionInputs): Promise<{profileFolder: string}> => {
       {
         env: {
           ...process.env,
+          // prepend the custom dist/bin folder to the path, to run our custom node script instead of the regular node
+          PATH: `${customBinPath}:${process.env.PATH}`,
           PYTHONMALLOC: "malloc",
           PYTHONHASHSEED: "0",
-          CODSPEED_V8_FLAGS: [
-            "--hash-seed=1",
-            "--random-seed=1",
-            "--no-randomize-hashes",
-            "--no-scavenge-task",
-            "--no-opt ",
-            "--predictable ",
-            "--predictable-gc-schedule",
-          ].join(" "),
           ARCH: arch,
           CODSPEED_ENV: "github",
         },