Fixes for Turing 0.41

[penelopeysm]

Assorted fixes to get the new Turing release to work nicely with DPPL.

Things included in this PR:

• setleafcontext(model, context) convenience method (closes setleafcontext(::Model, ::AbstractContext) #993)
• Default initial_params in the default sample call for DynamicPPL models (otherwise AbstractMCMC will insert nothing and it will error)
• Improved signatures for some context methods

[github-actions]

Benchmark Report for Commit 6e67ce7

Computer Information

Julia Version 1.11.7
Commit f2b3dbda30a (2025-09-08 12:10 UTC)
Build Info:
  Official https://julialang.org/ release
Platform Info:
  OS: Linux (x86_64-linux-gnu)
  CPU: 4 × AMD EPYC 7763 64-Core Processor
  WORD_SIZE: 64
  LLVM: libLLVM-16.0.6 (ORCJIT, znver3)
Threads: 1 default, 0 interactive, 1 GC (on 4 virtual cores)

Benchmark Results

┌───────────────────────┬───────┬─────────────┬───────────────────┬────────┬────────────────┬─────────────────┐
│                 Model │   Dim │  AD Backend │           VarInfo │ Linked │ t(eval)/t(ref) │ t(grad)/t(eval) │
├───────────────────────┼───────┼─────────────┼───────────────────┼────────┼────────────────┼─────────────────┤
│ Simple assume observe │     1 │ forwarddiff │             typed │  false │            8.9 │             1.5 │
│           Smorgasbord │   201 │ forwarddiff │             typed │  false │          666.0 │            42.3 │
│           Smorgasbord │   201 │ forwarddiff │ simple_namedtuple │   true │          431.1 │            52.0 │
│           Smorgasbord │   201 │ forwarddiff │           untyped │   true │         1158.9 │            31.7 │
│           Smorgasbord │   201 │ forwarddiff │       simple_dict │   true │         6930.4 │            26.4 │
│           Smorgasbord │   201 │ reversediff │             typed │   true │         1044.5 │            40.9 │
│           Smorgasbord │   201 │    mooncake │             typed │   true │         1030.0 │             4.7 │
│    Loop univariate 1k │  1000 │    mooncake │             typed │   true │         6013.0 │             4.3 │
│       Multivariate 1k │  1000 │    mooncake │             typed │   true │         1021.1 │             9.4 │
│   Loop univariate 10k │ 10000 │    mooncake │             typed │   true │        66962.1 │             3.9 │
│      Multivariate 10k │ 10000 │    mooncake │             typed │   true │         8823.8 │            10.5 │
│               Dynamic │    10 │    mooncake │             typed │   true │          150.3 │            10.6 │
│              Submodel │     1 │    mooncake │             typed │   true │           13.1 │             4.9 │
│                   LDA │    12 │ reversediff │             typed │   true │         1049.5 │             2.1 │
└───────────────────────┴───────┴─────────────┴───────────────────┴────────┴────────────────┴─────────────────┘

[codecov]

Codecov Report

❌ Patch coverage is 91.30435% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 82.39%. Comparing base (11d0b69) to head (fb669a1).
⚠️ Report is 1 commits behind head on breaking.

Files with missing lines	Patch %	Lines
src/sampler.jl	60.00%	2 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##           breaking    #1057      +/-   ##
============================================
- Coverage     82.43%   82.39%   -0.04%     
============================================
  Files            42       42              
  Lines          3815     3818       +3     
============================================
+ Hits           3145     3146       +1     
- Misses          670      672       +2     

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[yebai]

One minor comment I have is that we can warn the user if they pass initial_parameters instead of initial_params? I find this a bit confusing since some most other keyword arguments don't use abbrevation, and when initial_parameters is passed, it got a silent expected behaviour.

[github-actions]

DynamicPPL.jl documentation for PR #1057 is available at:
https://TuringLang.github.io/DynamicPPL.jl/previews/PR1057/

[mhauru]

All good