fix(cli): remove usage of deprecated npm env var from arg parser

This removes some code from our argument parsing implementation which
would look for an environment variable (`npm_config_argv`) set by npm
and, if present, merge CLI flags found their into the ones already
present on `process.argv`.

We want to remove this for two reasons:

- `npm_config_argv` is deprecated in `npm`, so in newer versions of the
  package manager it is no longer set and our code referencing it is
  effectively doing nothing
- `yarn` v1.x still sets it (presumably for compatibility with `npm`
  that hasn't been removed yet, which causes an inconsistency between
  `npm` and `yarn` where certain `package.json` scripts will run without
  issue in `npm` but fail in `yarn` (see #3482)

Accordingly, this commit deletes the offending function from
`src/cli/parse-flags.ts` and makes a few related changes at call sites,
etc which are necessary due to that change.

This commit also refactors the spec file for `parse-flags.ts` to remove
redundant tests. Because all of the supported CLI arguments (i.e. those
added to `knownArgs`) are defined in `ReadonlyArray<string>` variables
we can do a lot of exhaustive testing of all the arguments, set in the
various possible permutations, etc, so we don't need to define a bunch
of individual tests. Accordingly, the test file is refactored to remove
redundant tests, add a few more test cases for the exhaustive tests,
organize things a bit more with `describe` blocks, and ensure that we
have good tests around all off the 'edge-case-ey' things.

src/cli/parse-flags.ts

@@ -1,4 +1,4 @@
-import { CompilerSystem, LogLevel, LOG_LEVELS, TaskCommand } from '../declarations';
+import { LogLevel, LOG_LEVELS, TaskCommand } from '../declarations';
 import { dashToPascalCase, toDashCase } from '@utils';
 import {
   BOOLEAN_CLI_ARGS,
@@ -19,11 +19,10 @@ import {
 /**
  * Parse command line arguments into a structured `ConfigFlags` object
  *
- * @param args an array of config flags
- * @param sys an optional compiler system
+ * @param args an array of CLI flags
  * @returns a structured ConfigFlags object
  */
-export const parseFlags = (args: string[], sys?: CompilerSystem): ConfigFlags => {
+export const parseFlags = (args: string[]): ConfigFlags => {
   const flags: ConfigFlags = createConfigFlags();
 
   // cmd line has more priority over npm scripts cmd
@@ -33,17 +32,6 @@ export const parseFlags = (args: string[], sys?: CompilerSystem): ConfigFlags =>
   }
   parseArgs(flags, flags.args);
 
-  if (sys && sys.name === 'node') {
-    const envArgs = getNpmConfigEnvArgs(sys);
-    parseArgs(flags, envArgs);
-
-    envArgs.forEach((envArg) => {
-      if (!flags.args.includes(envArg)) {
-        flags.args.push(envArg);
-      }
-    });
-  }
-
   if (flags.task != null) {
     const i = flags.args.indexOf(flags.task);
     if (i > -1) {
@@ -344,19 +332,3 @@ const isLogLevel = (maybeLogLevel: string): maybeLogLevel is LogLevel =>
   //
   // see microsoft/TypeScript#31018 for some discussion of this
   LOG_LEVELS.includes(maybeLogLevel as any);
-
-const getNpmConfigEnvArgs = (sys: CompilerSystem) => {
-  // process.env.npm_config_argv
-  // {"remain":["4444"],"cooked":["run","serve","--port","4444"],"original":["run","serve","--port","4444"]}
-  let args: string[] = [];
-  try {
-    const npmConfigArgs = sys.getEnvironmentVar('npm_config_argv');
-    if (npmConfigArgs) {
-      args = JSON.parse(npmConfigArgs).original as string[];
-      if (args[0] === 'run') {
-        args = args.slice(2);
-      }
-    }
-  } catch (e) {}
-  return args;
-};

src/cli/run.ts

@@ -23,7 +23,7 @@ export const run = async (init: d.CliInitOptions) => {
   const { args, logger, sys } = init;
 
   try {
-    const flags = parseFlags(args, sys);
+    const flags = parseFlags(args);
     const task = flags.task;
 
     if (flags.debug || flags.verbose) {