Change Activity.DefaultIdFormat to W3C

[shirhatti]

In 5.0, we should change the Default value for Activity.DefaultIdFormat to ActivityIdFormat.W3C.

cc @SergeyKanzhelev

[SergeyKanzhelev]

Thank you for filing it!

[shirhatti]

@tarekgh Can we get this work scheduled?

cc @davidfowl @noahfalk

[tarekgh]

@shirhatti @noahfalk this looks a breaking change. did we decide we are going to do it? is it an acceptable change.

@tommcdon @noahfalk any idea who should do this work?

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[davidfowl]

It’s not breaking if you have a mix of 3.1 and 5.0 apps. It’s only breaking if you mix 2.x and >= 5.x apps specifically if you have a 5.0 app with w3c making a request to a 2.x app. This is broken today if you explicitly set it but it work fine if you do the same with a 3.x app (since Activity detects the format)

[noahfalk]

@shirhatti - If I remember right the last time we talked about this you were looking into what kind of notification we should do to customers. Did we ever reach a conclusion?

did we decide we are going to do it? is it an acceptable change.

I am in favor of doing it. If there is a broader process the BCL team likes to do or more consensus to gather could you let me know?

@tommcdon @noahfalk any idea who should do this work?

I was hoping it could be you but let me know if that is a problem. Code-wise I expect this is a tiny change:

1. Assign W3C to the s_defaultIdFormat field
2. Add a compat switch so that customers can opt-out of the change if it breaks their app (hopefully this is very rare)

[tarekgh]

@noahfalk I'll try to get into this then at some time in the next couple of weeks if it is not earlier. We need to talk about the config switch as from what I am hearing from @davidfowl will not be a serious breaking except with some configuration (mixing 2.x with 5.x). Usually, we don't use config switches in core except for serious breaking cases. We can delay the switch till we fix someone broken and we can try service the library with the switch support.

[noahfalk]

We need to talk about the config switch

I'm happy to chat, but up-front I'd be nervous about making a change like this without an opt-out.

We can delay the switch till we fix someone broken and we can try service the library with the switch support.

This sounds hugely expensive vs. adding it now. I'm not sure why we'd want to be this reserved about it? I think the odds of at least one customer wanting this switch is pretty good.