Warn when concretising a dynamic index on a GrowableArray & when creating a GrowableArray

[penelopeysm]

Closes #1241
Closes #1251

With this PR:

julia> using DynamicPPL

julia> vnt = @vnt begin
          x[1] := 1.0
       end
┌ Warning: Creating a growable `Base.Array` of dimension 1 to store values. This may not match the actual type or size of the actual `AbstractArray` that will be used inside the DynamicPPL model.
│
│  If this is not the type or size that you expect, please see: https://turinglang.org/docs/uri/growablearray
└ @ DynamicPPL.VarNamedTuples ~/ppl/dppl/src/varnamedtuple/partial_array.jl:823
VarNamedTuple
└─ x => PartialArray size=(1,) data::DynamicPPL.VarNamedTuples.GrowableArray{Float64, 1}
        └─ (1,) => 1.0

julia> vnt[@varname(x[end])]
┌ Warning: Returning a `Base.Array` with a presumed size based on the indices used to set values; but this may not be the actual type or size of the actual `AbstractArray` that was inside the DynamicPPL model. You should inspect the returned result to make sure that it has the correct value.
│
│ To find out how to avoid this warning, please see: https://turinglang.org/docs/uri/growablearray
└ @ DynamicPPL.VarNamedTuples ~/ppl/dppl/src/varnamedtuple/partial_array.jl:812
1.0

Previously neither of these would warn.

[github-actions]

Benchmark Report

• this PR's head: 4c413f91264e7bef995a7ffa6198ac693840ffed
• base branch: e14912c541b1a9301b261c5199cc3b964e99863c

Computer Information

Julia Version 1.11.8
Commit cf1da5e20e3 (2025-11-06 17:49 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

┌───────────────────────┬───────┬─────────────┬────────┬───────────────────────────────┬────────────────────────────┬─────────────────────────────────┐
│                       │       │             │        │       t(eval) / t(ref)        │     t(grad) / t(eval)      │        t(grad) / t(ref)         │
│                       │       │             │        │ ─────────┬──────────┬──────── │ ───────┬─────────┬──────── │ ──────────┬───────────┬──────── │
│                 Model │   Dim │  AD Backend │ Linked │     base │  this PR │ speedup │   base │ this PR │ speedup │      base │   this PR │ speedup │
├───────────────────────┼───────┼─────────────┼────────┼──────────┼──────────┼─────────┼────────┼─────────┼─────────┼───────────┼───────────┼─────────┤
│               Dynamic │    10 │    mooncake │   true │   397.72 │   380.90 │    1.04 │  10.90 │   11.34 │    0.96 │   4336.91 │   4321.25 │    1.00 │
│                   LDA │    12 │ reversediff │   true │  2802.21 │  2728.02 │    1.03 │   4.96 │    4.89 │    1.01 │  13899.42 │  13343.23 │    1.04 │
│   Loop univariate 10k │ 10000 │    mooncake │   true │ 66982.16 │ 72380.60 │    0.93 │   5.06 │    5.09 │    0.99 │ 339095.46 │ 368616.21 │    0.92 │
├───────────────────────┼───────┼─────────────┼────────┼──────────┼──────────┼─────────┼────────┼─────────┼─────────┼───────────┼───────────┼─────────┤
│    Loop univariate 1k │  1000 │    mooncake │   true │  6666.86 │  8021.71 │    0.83 │   5.08 │    4.21 │    1.21 │  33883.89 │  33750.03 │    1.00 │
│      Multivariate 10k │ 10000 │    mooncake │   true │ 74629.73 │ 74777.68 │    1.00 │   4.49 │    4.42 │    1.02 │ 334827.40 │ 330366.53 │    1.01 │
│       Multivariate 1k │  1000 │    mooncake │   true │  3529.87 │  3663.39 │    0.96 │   9.50 │    9.20 │    1.03 │  33529.74 │  33685.06 │    1.00 │
├───────────────────────┼───────┼─────────────┼────────┼──────────┼──────────┼─────────┼────────┼─────────┼─────────┼───────────┼───────────┼─────────┤
│ Simple assume observe │     1 │ forwarddiff │  false │     2.67 │     2.61 │    1.02 │   3.87 │    3.95 │    0.98 │     10.32 │     10.32 │    1.00 │
│           Smorgasbord │   201 │ forwarddiff │  false │  1113.95 │  1100.72 │    1.01 │  68.75 │  133.81 │    0.51 │  76585.15 │ 147282.62 │    0.52 │
│           Smorgasbord │   201 │      enzyme │   true │  1518.26 │  1531.50 │    0.99 │   6.95 │    6.70 │    1.04 │  10547.81 │  10257.31 │    1.03 │
├───────────────────────┼───────┼─────────────┼────────┼──────────┼──────────┼─────────┼────────┼─────────┼─────────┼───────────┼───────────┼─────────┤
│           Smorgasbord │   201 │ forwarddiff │   true │  1549.09 │  1521.43 │    1.02 │  63.39 │   64.58 │    0.98 │  98195.46 │  98258.70 │    1.00 │
│           Smorgasbord │   201 │    mooncake │   true │  1607.22 │  1534.66 │    1.05 │   5.37 │    5.62 │    0.96 │   8631.13 │   8622.11 │    1.00 │
│           Smorgasbord │   201 │ reversediff │   true │  1512.20 │  1528.34 │    0.99 │ 103.07 │  100.27 │    1.03 │ 155861.67 │ 153252.74 │    1.02 │
├───────────────────────┼───────┼─────────────┼────────┼──────────┼──────────┼─────────┼────────┼─────────┼─────────┼───────────┼───────────┼─────────┤
│              Submodel │     1 │    mooncake │   true │     3.27 │     3.27 │    1.00 │  52.88 │   96.43 │    0.55 │    172.96 │    315.70 │    0.55 │
└───────────────────────┴───────┴─────────────┴────────┴──────────┴──────────┴─────────┴────────┴─────────┴─────────┴───────────┴───────────┴─────────┘

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 78.57%. Comparing base (e14912c) to head (4c413f9).
⚠️ Report is 2 commits behind head on breaking.

Additional details and impacted files

@@              Coverage Diff              @@
##           breaking    #1253       +/-   ##
=============================================
+ Coverage     36.98%   78.57%   +41.59%     
=============================================
  Files            46       46               
  Lines          3572     3608       +36     
=============================================
+ Hits           1321     2835     +1514     
+ Misses         2251      773     -1478     

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[github-actions]

DynamicPPL.jl documentation for PR #1253 is available at:
https://TuringLang.github.io/DynamicPPL.jl/previews/PR1253/