cli: add lifecycle event env to node --run

Author: anonrig

doc/api/cli.md

@@ -1847,6 +1847,10 @@ Modules preloaded with `--require` will run before modules preloaded with `--imp
 
 <!-- YAML
 added: v22.0.0
+changes:
+  - version: REPLACEME
+    pr-url: https://github.com/nodejs/node/pull/XXXXXX
+    description: `NODE_LIFECYCLE_EVENT` environment variable is added.
 -->
 
 > Stability: 1.1 - Active development
@@ -1887,6 +1891,13 @@ are:
 * Running `pre` or `post` scripts in addition to the specified script.
 * Defining package manager-specific environment variables.
 
+#### Environment variables
+
+The following environment variables are set when running a script with `--run`:
+
+* `NODE_LIFECYCLE_EVENT`: The name of the script being run. For example, if
+  `--run` is used to run `test`, the value of this variable will be `test`.
+
 ### `--secure-heap=n`
 
 <!-- YAML

src/node_task_runner.cc

@@ -12,6 +12,7 @@ static constexpr const char* bin_path = "/node_modules/.bin";
 #endif  // _WIN32
 
 ProcessRunner::ProcessRunner(std::shared_ptr<InitializationResultImpl> result,
+                             std::string_view script_name,
                              std::string_view command,
                              const PositionalArgs& positional_args) {
   memset(&options_, 0, sizeof(uv_process_options_t));
@@ -85,6 +86,10 @@ ProcessRunner::ProcessRunner(std::shared_ptr<InitializationResultImpl> result,
   }
   uv_os_free_environ(env_items, env_count);
 
+  // Add NODE_LIFECYCLE_EVENT environment variable to the environment
+  // to indicate which script is being run.
+  env_vars_.push_back("NODE_LIFECYCLE_EVENT=" + std::string(script_name));
+
   // Use the stored reference on the instance.
   options_.file = file_.c_str();
 
@@ -276,7 +281,7 @@ void RunTask(std::shared_ptr<InitializationResultImpl> result,
     return;
   }
 
-  auto runner = ProcessRunner(result, command, positional_args);
+  auto runner = ProcessRunner(result, command_id, command, positional_args);
   runner.Run();
 }
 

src/node_task_runner.h

@@ -52,6 +52,7 @@ class ProcessRunner {
 };
 
 void RunTask(std::shared_ptr<InitializationResultImpl> result,
+             std::string_view script_name,
              std::string_view command_id,
              const PositionalArgs& positional_args);
 PositionalArgs GetPositionalArgs(const std::vector<std::string>& args);