test(parity): run the oracle with this process's node

The parity cases run through `/bin/sh -lc`, and a login shell rebuilds
PATH from the system profile. On the docker8 fleet that puts the image's
node 22 (/usr/local/bin) before setup-node's node 24, so the oracle
loaded the reference's node-pty, built for node 24, failed, and printed
node-pty's innerError on stderr: read-configuration.compose-path-terminal
and read-configuration.missing-required differed on every run there.
The oracle's command now names the node on the test process's PATH by
its absolute path.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Author: aledbf

internal/cli/parity_matrix_test.go

@@ -222,7 +222,7 @@ func TestParityMatrix(t *testing.T) {
 		}
 	})
 
-	cliTS := envOr("CLI_TS", "node "+filepath.Join(repoRoot, "reference", "devcontainer.js"))
+	cliTS := envOr("CLI_TS", defaultParityTSCLI(repoRoot))
 	cliGO := envOr("CLI_GO", filepath.Join(repoRoot, "devcontainer"))
 	defaultTimeout := 60 * time.Second
 	// Runtime lane default; overridable via PARITY_RUNTIME_TIMEOUT (e.g. "10m")
@@ -1066,7 +1066,7 @@ func parityEnv(caseID, side, repoRoot string, isolateCompose bool) map[string]st
 		// no container → "Dev container not found"). Mirror the cliGO/cliTS defaults
 		// (lines above) so setup and the measured command always agree.
 		"PARITY_CLI_GO": envOr("CLI_GO", filepath.Join(repoRoot, "devcontainer")),
-		"PARITY_CLI_TS": envOr("CLI_TS", "node "+filepath.Join(repoRoot, "reference", "devcontainer.js")),
+		"PARITY_CLI_TS": envOr("CLI_TS", defaultParityTSCLI(repoRoot)),
 		// Newer BuildKit attaches provenance/SBOM attestations by default, wrapping
 		// the feature-content image in an attestation manifest list. That breaks the
 		// TS CLI's `COPY --from=dev_containers_feature_content_source ...` feature
@@ -1147,6 +1147,20 @@ func findRepoRoot(t *testing.T) string {
 	}
 }
 
+// defaultParityTSCLI is the oracle's command line: the node on this process's
+// PATH, by its absolute path, running reference/devcontainer.js. The cases run
+// through `/bin/sh -lc`, and a login shell rebuilds PATH from the system
+// profile: on a runner whose setup-node node is not the system one (the docker8
+// fleet's image has node 22 in /usr/local/bin) a bare `node` would then load the
+// reference's native node-pty, built for the setup-node version, and fail.
+func defaultParityTSCLI(repoRoot string) string {
+	node, err := exec.LookPath("node")
+	if err != nil {
+		node = "node"
+	}
+	return node + " " + filepath.Join(repoRoot, "reference", "devcontainer.js")
+}
+
 func envOr(key, fallback string) string {
 	if v := os.Getenv(key); v != "" {
 		return v

internal/cli/parity_setup_binary_test.go

@@ -34,7 +34,8 @@ func TestParitySetupUsesLaneBinary(t *testing.T) {
 	if got := env["PARITY_CLI_GO"]; got != filepath.Join("/repo", "devcontainer") {
 		t.Errorf("PARITY_CLI_GO default = %q, want the repo-root binary", got)
 	}
-	if got, want := env["PARITY_CLI_TS"], "node "+filepath.Join("/repo", "reference", "devcontainer.js"); got != want {
+	// The oracle's node is this process's, by absolute path (defaultParityTSCLI).
+	if got, want := env["PARITY_CLI_TS"], defaultParityTSCLI("/repo"); got != want {
 		t.Errorf("PARITY_CLI_TS default = %q, want %q", got, want)
 	}
 

internal/cli/parity_ts_cli_test.go

@@ -0,0 +1,28 @@
+package cli
+
+import (
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+)
+
+// The oracle's node is the one on this process's PATH, named by its absolute
+// path, so a login shell's PATH cannot swap it for another node.
+func TestDefaultParityTSCLIUsesThisProcessNode(t *testing.T) {
+	dir := t.TempDir()
+	node := filepath.Join(dir, "node")
+	if err := os.WriteFile(node, []byte("#!/bin/sh\n"), 0o755); err != nil {
+		t.Fatal(err)
+	}
+	t.Setenv("PATH", dir)
+	got := defaultParityTSCLI("/repo")
+	if want := node + " " + filepath.Join("/repo", "reference", "devcontainer.js"); got != want {
+		t.Errorf("command = %q, want %q", got, want)
+	}
+
+	t.Setenv("PATH", t.TempDir())
+	if got := defaultParityTSCLI("/repo"); !strings.HasPrefix(got, "node ") {
+		t.Errorf("without node on PATH the command = %q, want a bare node for the shell to find", got)
+	}
+}