fix(e2e): bound shared helper log output

scripts/lib/openclaw-e2e-instance.sh

@@ -174,6 +174,14 @@ NODE
     "$timeout_bin" "$timeout_value" "$@"
   fi
 }
+openclaw_e2e_print_log() {
+  local path="$1"
+  local max_bytes="${OPENCLAW_E2E_LOG_TAIL_BYTES:-262144}"
+  local max_lines="${OPENCLAW_E2E_LOG_TAIL_LINES:-120}"
+  [ -f "$path" ] || return 0
+  echo "--- $path ---"
+  tail -c "$max_bytes" "$path" 2>/dev/null | tail -n "$max_lines" || tail -n "$max_lines" "$path" || true
+}
 openclaw_e2e_install_package() {
   local log_file="$1"
   local label="${2:-mounted OpenClaw package}"
@@ -203,9 +211,7 @@ openclaw_e2e_install_package() {
     fi
     echo "npm install failed for $label" >&2
     if [ -f "$log_file" ]; then
-      while IFS= read -r line || [ -n "$line" ]; do
-        printf '%s\n' "$line" >&2
-      done <"$log_file"
+      openclaw_e2e_print_log "$log_file" >&2
     fi
     exit 1
   fi
@@ -470,7 +476,7 @@ openclaw_e2e_run_logged() {
   log_path="$(mktemp "$log_root/openclaw-${safe_label}.XXXXXX.log")"
   OPENCLAW_E2E_LAST_LOG_PATH="$log_path"
   export OPENCLAW_E2E_LAST_LOG_PATH
-  openclaw_e2e_run_command "$@" >"$log_path" 2>&1 || { cat "$log_path"; exit 1; }
+  openclaw_e2e_run_command "$@" >"$log_path" 2>&1 || { openclaw_e2e_print_log "$log_path"; exit 1; }
 }
 openclaw_e2e_run_command() {
   local timeout_value="${OPENCLAW_E2E_COMMAND_TIMEOUT:-300s}"
@@ -490,7 +496,6 @@ openclaw_e2e_enable_openclaw_cli_timeout() {
 openclaw_e2e_dump_logs() {
   local path
   for path in "$@"; do
-    [ -f "$path" ] || continue
-    echo "--- $path ---"; tail -n "${OPENCLAW_E2E_LOG_TAIL_LINES:-120}" "$path" || true
+    openclaw_e2e_print_log "$path"
   done
 }

test/scripts/openclaw-e2e-instance.test.ts

@@ -445,6 +445,54 @@ describe("scripts/lib/openclaw-e2e-instance.sh", () => {
     }
   });
 
+  it("bounds npm install failure logs to the configured tail", () => {
+    const tempDir = fs.mkdtempSync(path.join(os.tmpdir(), "openclaw-e2e-instance-install-log-"));
+    try {
+      const timeoutArgsPath = path.join(tempDir, "timeout-args.txt");
+      const logPath = path.join(tempDir, "install.log");
+      const packagePath = path.join(tempDir, "openclaw.tgz");
+      const prefixPath = path.join(tempDir, "prefix");
+      writePackageFixture(packagePath);
+      writeFakeTimeout(path.join(tempDir, "timeout"), true);
+      writeBashExecutable(path.join(tempDir, "npm"), [
+        'printf "DO_NOT_PRINT_OLD_NPM_LOG\\n"',
+        'i=0; while [ "$i" -lt 220 ]; do printf "x"; i=$((i + 1)); done',
+        'printf "\\nrecent npm tail\\n"',
+        "exit 42",
+      ]);
+
+      const result = spawnSync(
+        "/bin/bash",
+        [
+          "-c",
+          [
+            "set -euo pipefail",
+            `source ${shellQuote(helperPath)}`,
+            `openclaw_e2e_install_package ${shellQuote(logPath)} ${shellQuote("fixture package")} ${shellQuote(prefixPath)}`,
+          ].join("; "),
+        ],
+        {
+          encoding: "utf8",
+          env: shellTestEnv({
+            PATH: `${tempDir}${path.delimiter}${hostPath}`,
+            OPENCLAW_CURRENT_PACKAGE_TGZ: packagePath,
+            OPENCLAW_E2E_LOG_TAIL_BYTES: "80",
+            OPENCLAW_E2E_NPM_INSTALL_TIMEOUT: "42s",
+            OPENCLAW_TEST_TIMEOUT_ARGS: timeoutArgsPath,
+          }),
+        },
+      );
+
+      expect(result.status).toBe(1);
+      expect(result.stderr).toContain("npm install failed for fixture package");
+      expect(result.stderr).toContain("recent npm tail");
+      expect(result.stderr).not.toContain("DO_NOT_PRINT_OLD_NPM_LOG");
+      expect(fs.readFileSync(logPath, "utf8")).toContain("DO_NOT_PRINT_OLD_NPM_LOG");
+    } finally {
+      fs.rmSync(tempDir, { force: true, recursive: true });
+    }
+  });
+
   it("bounds commands with the Node watchdog when timeout is unavailable", () => {
     const tempDir = fs.mkdtempSync(path.join(os.tmpdir(), "openclaw-e2e-instance-node-watchdog-"));
     try {
@@ -912,6 +960,54 @@ exit 1
     }
   });
 
+  it("bounds logged command failure output to the configured tail", () => {
+    const tempDir = fs.mkdtempSync(path.join(os.tmpdir(), "openclaw-e2e-instance-run-log-tail-"));
+    const logLabel = path.basename(tempDir);
+    const logDir = path.join(tempDir, "logs");
+    try {
+      const timeoutArgsPath = path.join(tempDir, "timeout-args.txt");
+      writeFakeTimeout(path.join(tempDir, "timeout"), true);
+      writeBashExecutable(path.join(tempDir, "fixture-command"), [
+        'printf "DO_NOT_PRINT_OLD_COMMAND_LOG\\n"',
+        'i=0; while [ "$i" -lt 220 ]; do printf "x"; i=$((i + 1)); done',
+        'printf "\\nrecent command tail\\n"',
+        "exit 23",
+      ]);
+
+      const result = spawnSync(
+        "/bin/bash",
+        [
+          "-c",
+          [
+            "set -euo pipefail",
+            `source ${shellQuote(helperPath)}`,
+            `openclaw_e2e_run_logged ${shellQuote(logLabel)} fixture-command`,
+          ].join("; "),
+        ],
+        {
+          encoding: "utf8",
+          env: shellTestEnv({
+            PATH: `${tempDir}${path.delimiter}${hostPath}`,
+            OPENCLAW_E2E_COMMAND_TIMEOUT: "17s",
+            OPENCLAW_E2E_LOG_DIR: logDir,
+            OPENCLAW_E2E_LOG_TAIL_BYTES: "80",
+            OPENCLAW_TEST_TIMEOUT_ARGS: timeoutArgsPath,
+          }),
+        },
+      );
+
+      expect(result.status).toBe(1);
+      expect(result.stdout).toContain("recent command tail");
+      expect(result.stdout).not.toContain("DO_NOT_PRINT_OLD_COMMAND_LOG");
+      const [logFile] = fs.readdirSync(logDir);
+      expect(fs.readFileSync(path.join(logDir, logFile), "utf8")).toContain(
+        "DO_NOT_PRINT_OLD_COMMAND_LOG",
+      );
+    } finally {
+      fs.rmSync(tempDir, { force: true, recursive: true });
+    }
+  });
+
   it("installs the trash shim under isolated test state", () => {
     const tempDir = fs.mkdtempSync(path.join(os.tmpdir(), "openclaw-e2e-trash-shim-"));
     try {