Null safety

[WieFel]

Closes #85

[WieFel]

@daadu need your help on some things

[WieFel]

Also: should example/ and demo/ also be migrated? @daadu

For demo we need gallerize package to be migrated, which still waits on flutter_highlight (git-touch/highlight.dart#18) to be migrated.

[daadu]

@WieFel Should we merge this to master?

Or release "null-saftey" to different version series "v0.6.x". This is until we are supporting "non-null safety" in v0.5.x.

Any new fix, will need to be merged with both. Later we can merge them.

[daadu]

@WieFel Should we merge this to master?

Or release "null-saftey" to different version series "v0.6.x". This is until we are supporting "non-null safety" in v0.5.x.

Any new fix, will need to be merged with both. Later we can merge them.

@WieFel Give me your views on it.

If the user does not uprgade his project to "null safety", will our package break things? if that is true, then we can merge this to master.

[WieFel]

If the user does not uprgade his project to "null safety", will our package break things? if that is true, then we can merge this to master.

I just played around with it. I downgraded Flutter to version 1.22.6 and created a sample app into which I imported backdrop null-safety branch. When doing flutter pub get, the following error arises:

The current Dart SDK version is 2.10.5.

Because backdrop_nullsafety_test depends on backdrop from git which requires SDK version >=2.12.0 <3.0.0, version solving failed.
pub get failed (1; Because backdrop_nullsafety_test depends on backdrop from git which requires SDK version >=2.12.0 <3.0.0, version solving failed.)

(where backdrop_nullsafety_test is the name of my freshly created app)

Thus, by applying null-safe code to master we would force users to upgrade to Flutter 2.0.0, which isn't so bad in my opinion.

[WieFel]

@WieFel Should we merge this to master?

Or release "null-saftey" to different version series "v0.6.x". This is until we are supporting "non-null safety" in v0.5.x.

Any new fix, will need to be merged with both. Later we can merge them.

@daadu In my opinion it requires just additional effort if we maintain a "null-safety" and "non-null-safety" version in two different branches.
Also other packages don't do it, like: cupertino_icons, flutter_launcher_icons, ...

Those are way more popular than backdrop. So I would say if we just release the new null-safe version as 0.6.0, we are fine.

@proninyaroslav what do you think about this?

[proninyaroslav]

@WieFel
The library is still actively developing and I don't think that such a strict separation is necessary, thereby creating legacy at an early stage. API essentially remains the same. Switching to the null safety version is not painful when using backdrop in a project.

[daadu]

@WieFel @proninyaroslav Ok then, lets release this as v0.6.0, with a note in README that explains the breaking change.

@WieFel Can you add that note?

[daadu]

@WieFel Can you add that note?

Added myself.

[WieFel]

LGTM 🎉

[daadu]

This fix/feature has landed with v0.6.0 on pub.dev.