2.x prep

[brettmc]

Initial work for a 2.x branch:

• make PHP 8.2 the minimum
• make 2.x-dev alias
• bump phpunit dependency
• run rector over the codebase and implement its recommended 8.2 changes
• update SPI PackageDependency values

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 2 lines in your changes missing coverage. Please review.

Project coverage is 73.23%. Comparing base (b515b6b) to head (397d818).
Report is 1 commits behind head on 2.x.

Files with missing lines	Patch %	Lines
src/Context/ZendObserverFiber.php	0.00%	2 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##                2.x    #1463      +/-   ##
============================================
- Coverage     73.27%   73.23%   -0.04%     
+ Complexity     2683     2682       -1     
============================================
  Files           387      387              
  Lines          8014     8014              
============================================
- Hits           5872     5869       -3     
- Misses         2142     2145       +3     

Flag	Coverage Δ
8.1	?
8.2	?
8.3	?
8.4	73.20% <0.00%> (-0.02%)	⬇️
8.5	73.20% <0.00%> (ø)

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Files with missing lines	Coverage Δ
src/Context/ZendObserverFiber.php	0.00% <0.00%> (ø)

... and 3 files with indirect coverage changes

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[Nevay]

We should consider keeping the API and Context packages on 1.x; bumping these packages to a new major version requires updating every instrumentation package which might slow down adoption of an SDK 2.x release.

[brettmc]

That's reasonable. They will still exist in the 2.x branch (as will proto, semconv), but we can avoid releasing a new version until we do make a breaking change. I think the most likely trigger for this would be removing the registry in favour of SPI (and possibly removing globals initializers at the same time).

[Nevay]

FWIW I don't like changing readonly properties to readonly classes automatically as this might result in unnecessary diffs if we decide to change a property back to non-readonly / decide to add a non-readonly property in the future¹. I would prefer if we apply this change only to classes that should truly be readonly.

Footnotes

1. e.g. the DataInterface implementations have mutable $dataPoints in the upstream version of the metrics SDK to support MetricFilter. ↩

[brettmc]

reverted the rector changes and disabled this rule

[Nevay]

The version of this package is based on the https://github.com/open-telemetry/semantic-conventions version? -> should stay on 1.x.

[Nevay]

Same as above; based on https://github.com/open-telemetry/opentelemetry-proto version?

[brettmc]

I've pared this PR back:

• minimum PHP version is bumped to 8.2 for most components (but, we are not obligated to release a 2.x version of anything until we do have a breaking change)
• aliases, gitsplit config, github workflow config for 2.x
• package requirements kept at 1.x, until we do have 2.x version(s)