berry: [Bug] Syntax error in parsing package.json run scripts containing parameter substitutions or {}

Describe the bug

i am unable to run a npm script that contains parameter substitutions or the find command’s {} syntax with yarn 2, though yarn 1 and npm are both able to run it without issue.

To Reproduce

const {mkdir, writeFile} = require('fs/promises');

await mkdir('dist');

await writeFile('dist/example.d.ts', '// Example typescript definition file', 'utf8');

await packageJsonAndInstall({
  scripts: {
    "flowtypes": "find . -type f -not -path './node_modules/*' -regex '.*/dist/[^/]*.d.ts' -exec sh -c 'echo $1; echo ${1%.*.*}.js.flow;' _ {} \\;",
  }
});

await expect(yarn(`flowtypes`)).rejects.not.toThrow(`Command failed`);

Environment:

• OS: macOS 11.2.3
• Node version: 15.12.0
• Yarn version: 2.4.0-git.20210324.hash-a307bddb

Additional context

the real command i am trying to run is a find command that runs flowgen on every dist/*.d.ts file that isn’t in node_modules:

find . -type f -not -path './node_modules/*' -regex '.*/dist/[^/]*.d.ts' -exec sh -c 'yarn flowgen $1 -o ${1%.*.*}.js.flow' _ {} \\;

i tried to wrap the potentially problematic portions of the command with single quotes as recommended in https://github.com/yarnpkg/berry/issues/797#issuecomment-607724596 and in https://github.com/mysticatea/npm-run-all/issues/200, but i’m still hitting these syntax issues.

while this example is a pretty specific command that is unlikely to affect many people, a much more common issue is the case of "start": "run-p start:*" (or similar), which is a common pattern for packages and which breaks in yarn 2 unless start:* is wrapped in single quotes.