Boolean flags override even when not specified

When Yargs defaults are specified, they provide the value as flags to the command constructor. This means that when flags, command overrides, lerna json options and legacy options are merged, the flags will take precedence over any thing else because they have a value.

This can easily be reproduced by simply trying to use stream: true in the lerna.json. If you remove the option from, for example, RunCommand it works. Similarly, if you rename it from boolean to string, it continues to work. So it seems that while _.defaults() is doing the right thing (because false is a value, where undefined is not), providing a default that is considered a “value”, will break anything following the durable option convention.

Expected Behavior

Durable options should take precedence over Yargs defaults.

Current Behavior

Defaults override user-defined values not specified as flags.

Possible Solution

After digging a bit deeper, it seems that all we really have to do to get around this is to specify default: undefined to any option that is a boolean and doesn’t already have a default (because they default to false. When _.defaults() is called, they will then be overridden if they’re not specified by the user.

Steps to Reproduce

1. Put stream: true in the lerna.json
2. Run a command that should stream.
3. It won’t stream.

Context

• References #893.

[treshugart]

Wrote a test to confirm:

it("should prefer durable options over yargs defaults", () => {
  // yargs does this when default values are specified
  const instance = new TestBCommand([], {
    testOption: false,
    testOption2: 1
  }, testDir);
  expect(instance.options.testOption).toBe("b");
  expect(instance.options.testOption2).toBe("b");
});

[lock[bot]]

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