Bump rust to 1.78 and add feature to Cargo.toml according to libdatadog changes

[dubloom]

Description

libdatadog removed the set_cgroup_file feature. However it is used in some dd-trace-php tests. As we are not sure they can be removed and without any changes the tracer cannot be built, they added back but under a feature flag.

This PR activates the feature flag and therefore enable the tracer to be built again.

Reviewer checklist

• Test coverage seems ok.
• Appropriate labels assigned.

[iamluc]

@dubloom You probably have to update the reference of the libdatadog submodule to make it work

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 38.62%. Comparing base (205c6d8) to head (39df479).

❗ There is a different number of reports uploaded between BASE (205c6d8) and HEAD (39df479). Click for more details.

HEAD has 2 uploads less than BASE

Flag	BASE (205c6d8)	HEAD (39df479)
tracer-php	11	9

Additional details and impacted files

@@              Coverage Diff              @@
##             master    #3005       +/-   ##
=============================================
- Coverage     74.80%   38.62%   -36.19%     
  Complexity     2781     2781               
=============================================
  Files           112      112               
  Lines         11017    11017               
=============================================
- Hits           8241     4255     -3986     
- Misses         2776     6762     +3986     

Flag	Coverage Δ
tracer-php	38.62% <ø> (-36.19%)	⬇️

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see 42 files with indirect coverage changes

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[pr-commenter]

Benchmarks [ tracer ]

Benchmark execution time: 2024-12-20 13:11:47

Comparing candidate commit aae29fb in PR branch dubloom/add-cargo-feature-flag with baseline commit 0d57b55 in branch master.

Found 0 performance improvements and 3 performance regressions! Performance is the same for 175 metrics, 0 unstable metrics.

scenario:MessagePackSerializationBench/benchMessagePackSerialization

• 🟥 execution_time [+6.135µs; +8.285µs] or [+3.604%; +4.867%]

scenario:MessagePackSerializationBench/benchMessagePackSerialization-opcache

• 🟥 execution_time [+6.531µs; +8.309µs] or [+3.868%; +4.921%]

scenario:PDOBench/benchPDOBaseline

• 🟥 execution_time [+10.940µs; +15.320µs] or [+6.014%; +8.421%]

[ekump]

If this is for tests, you probably don't want this feature as a regular dependency. You can leave the ddcommon dependency as it was here, and under dev-dependencies add it again with this feature.

[dubloom]

i might do it wrong, but when i try, themake install command will fail because set_cgroup_file is not found.

[bwoebi]

It's for tests, but for PHP extension tests. Which are (also) run on release builds.

[pr-commenter]

Benchmarks [ profiler ]

Benchmark execution time: 2025-01-06 16:32:50

Comparing candidate commit 39df479 in PR branch dubloom/add-cargo-feature-flag with baseline commit 205c6d8 in branch master.

Found 0 performance improvements and 2 performance regressions! Performance is the same for 26 metrics, 8 unstable metrics.

scenario:walk_stack/50

• 🟥 wall_time [+723.415ns; +732.872ns] or [+4.989%; +5.054%]

scenario:walk_stack/99

• 🟥 wall_time [+725.946ns; +730.181ns] or [+5.034%; +5.063%]

[morrisonlevi]

Approved on the profiling side 👍🏻