Utilities using jcommander for boolean argument can be misleading

[xushiyan]

When people use Hudi utilities, many of them are not aware of --a-boolean-flag being present means true, and by following other args' pattern, they tend to set --a-boolean-flag true which resulted in

Exception in thread "main" org.apache.hudi.com.beust.jcommander.ParameterException: Was passed main parameter 'true' but no main parameter was defined in your arg class

To improve this experience, we should allow both ways to set a boolean arg. People should be able to

• omit or present a bool flag, omitting means using default value (can be true or false), present means true
• setting a true or false explicitly overwrites the default

To go further, any boolean arg used by utilities should be changed to default false. This may lead to breaking some usage, but it's a necessary step to align the expectations.

[danny0405]

+1, I got a lot of feedback because of these confusions. A explicit param true or false is more straight-forward.

[vinothchandar]

Can we list out all such boolean flags? are they all fixable without causing any side-effects 'silently' i.e changing behavior for the Hudi streamer run ..

This discussion will be more actionable with that analysis