initial values of flex

There's been a lot of discussion lately (after the Hamburg F2F) on what the initial values of 'flex' should be, and there are some concerns raised by Ojan with the resolution recorded there.

What are the best initial values for flex?

• Pros
  • It's easier to use alignment and auto margins
  • Easier for use cases that want some but not most items flexible, e.g. one item takes up all free space
• Cons
  • Doesn't have negative flexibility be default, which could help prevent overflow in many cases
  • Inconsistent with 'stretch' default in cross-dimension

• Pros
  • Negative flex is on by default, preventing overflow in many cases
  • Consistent with 'stretch' default in cross-dimension
• Cons
  • Harder to use alignment and margins, since have to turn off flex first
  • More work for use cases that want most items inflexible

• Pros
  • Negative flex is on by default, preventing overflow in many cases
  • Easy to use alignment and auto margins since positive free space is not flexed
  • Easy for use cases where free space is distributed to e.g. only one item
• Cons
  • Inconsistent with 'stretch' default in cross-dimension

The WG resolved on Proposal C.