[gdalle-bot]

Important

This PR was generated by a coding agent, please disregard it until @gdalle has reviewed it.

Restore AutoDiffractor support, which has been frozen at Diffractor v0.2.6 and untested in CI.

Diagnosis

Two independent problems:

1. Broadcasting bug in Diffractor v0.2.7 to v0.2.10 (New release broke DifferentiationInterface Diffractor.jl#290). The forward broadcast rule in src/stage1/broadcast.jl calls FwdMap{E}(f), but the only constructor is FwdMap{N,E}(f). So E = false lands in the N slot and we get MethodError: no method matching (FwdMap{false, E, T} where ...). Any f.(x) fails; map and scalar code are fine. The typo is still present on Diffractor main.
2. Registered Diffractor does not load on Julia 1.12: v0.2.10 fails to precompile there (method overwriting of copy(::IRCode)). Diffractor main (unreleased v0.2.11) does not load on 1.12 either (MethodList has no field mt), though it does on 1.13-rc3. DI cannot fix this.

Changes

• Extension: define the missing Diffractor.FwdMap{E}(f) constructor. This is type piracy, flagged as such in the code and docs; it is safe because compat is pinned to a single Diffractor version.
• Compat: Diffractor = "=0.2.6" → "=0.2.10".
• Tests: recreate the Diffractor backend test group (same scenarios as before its removal in chore: revamp testing CI with dedicated environments #926, plus a non-regression test for broadcasting) and reactivate it in CI on Julia 1.10 only (the matrix is 1.10 / 1.12 / 1.13, and the last two are excluded for this group).
• Docs, README, changelog updated to say that Diffractor works on Julia 1.10 and 1.11 only.

Testing

Draft PRs skip Julia 1.10 in CI, so the Diffractor group does not run here until the PR is marked ready. Ran the group locally: 3425/3425 tests pass on both Julia 1.10.11 and 1.11.9.

Possible follow-up

A one-line upstream PR to Diffractor (FwdMap{E} → FwdMap{N,E}) would let us drop the piracy once released.

Generated with Claude Opus 5.5 (claude-opus-5-5).

🤖 Generated with Claude Code

https://claude.ai/code/session_017t9zghYPb67WRAZPDhMCNt

[gdalle]

Okay this is actually useless, nevermind

[codecov]

Codecov Report

❌ Patch coverage is 0% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 93.92%. Comparing base (e068471) to head (11bf04e).

Files with missing lines	Patch %	Lines
...ractorExt/DifferentiationInterfaceDiffractorExt.jl	0.00%	2 Missing ⚠️
...ferentiationInterface/test/Back/Diffractor/test.jl	0.00%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##             main    #1079       +/-   ##
===========================================
+ Coverage   60.79%   93.92%   +33.13%     
===========================================
  Files         137      141        +4     
  Lines        8111     8197       +86     
===========================================
+ Hits         4931     7699     +2768     
+ Misses       3180      498     -2682     

Flag	Coverage Δ
DI	94.54% <0.00%> (+47.71%)	⬆️
DIT	92.20% <ø> (-6.29%)	⬇️

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