chore(jans-cedarling): improve wasm optimization build flags

[olehbozhok]

Move size-oriented release settings (opt-level = "z", lto = "fat", etc.) from workspace [profile.release] into a per-directory config-based profile under bindings/cedarling_wasm/.cargo/config.toml, so WASM builds stay size-optimized while native builds get speed optimization (opt-level = 3).

Prepare

• Read PR guidelines
• Read license information

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Description

Target issue

closes #14200

Implementation Details

Problem

The workspace [profile.release] in jans-cedarling/Cargo.toml used opt-level = "z", codegen-units = 1, and no LTO — all size-oriented settings. This applied to all release builds regardless of target, meaning native binding builds (Java, Python, Go, Uniffi) were unintentionally size-optimized instead of speed-optimized.

Solution

Split release profiles:

• jans-cedarling/Cargo.toml: restored default opt-level = 3 for native speed. Removed codegen-units = 1.
• bindings/cedarling_wasm/.cargo/config.toml (new): config-based [profile.release] overriding opt-level = "z", lto = "fat", codegen-units = 1, strip = true. Cargo applies this only when building from the cedarling_wasm directory (i.e. under wasm-pack).
• bindings/cedarling_wasm/Cargo.toml: moved wasm-opt flags to -Oz (aggressive size) and added required feature flags (bulk-memory, nontrapping-float-to-int, sign-ext, mutable-globals, multivalue) so fat-LTO output passes wasm-opt validation.

Why not custom profile + wasm-pack --profile

wasm-pack 0.14 ignores wasm-opt metadata for custom profile names, breaking --enable-* features.

Why config-based profile instead of [profile.*] in member Cargo.toml

Cargo silently ignores [profile.*] in non-root workspace members. Config-based profiles (.cargo/config.toml) are honored and merge over workspace root settings.

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Test and Document the changes

• Static code analysis has been run locally and issues have been fixed
• Relevant unit and integration tests have been added/updated
• Relevant documentation has been updated if any (i.e. user guides, installation and configuration guides, technical design docs etc)

Please check the below before submitting your PR. The PR will not be merged if there are no commits that start with docs: to indicate documentation changes or if the below checklist is not selected.

• I confirm that there is no impact on the docs due to the code changes in this PR.

Summary by CodeRabbit

• Chores
  • Refined build configurations to separate native speed-optimized releases from WebAssembly size-optimized releases, improving WASM package size and build outputs.
• Documentation
  • Added clarifying comments explaining which release profiles apply for workspace vs WASM crate builds.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: ASSERTIVE

Plan: Pro

Run ID: caa46a66-b28c-440f-b85b-08b8c1eec02d

📥 Commits

Reviewing files that changed from the base of the PR and between 1d761a3 and 48eaa86.

📒 Files selected for processing (1)

• jans-cedarling/bindings/cedarling_wasm/.cargo/config.toml

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📝 Walkthrough

Walkthrough

Cargo release profile was simplified at the workspace root; a crate-scoped .cargo/config.toml was added for bindings/cedarling_wasm to apply size/LTO/strip settings, and the crate's wasm-opt args were updated to -Oz plus required feature flags for LTO output.

Changes

WASM Compiler Optimization Fix

Layer / File(s)	Summary
Workspace profile rationalization jans-cedarling/Cargo.toml	Root [profile.release] is simplified to only debug-assertions = false, with comments documenting native vs WASM optimization intent.
WASM-specific optimization implementation jans-cedarling/bindings/cedarling_wasm/.cargo/config.toml, jans-cedarling/bindings/cedarling_wasm/Cargo.toml	Adds .cargo/config.toml scoped to the WASM crate applying opt-level = "z", lto = "fat", codegen-units = 1, and strip = true. Updates package.metadata.wasm-pack.profile.release.wasm-opt to -Oz and enables feature flags (--enable-reference-types, --enable-bulk-memory, --enable-nontrapping-float-to-int, --enable-sign-ext, --enable-mutable-globals, --enable-multivalue).

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20–30 minutes

Suggested labels

kind-feature, comp-jans-cedarling

Suggested reviewers

• dagregi
• haileyesus2433

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately describes the main change: improving WASM optimization build flags through profile and config reorganization.
Description check	✅ Passed	The PR description follows the template with all required sections completed: preparation checklist marked, target issue linked (#14200), implementation details provided with problem/solution analysis, and docs impact confirmed.
Linked Issues check	✅ Passed	The PR fully addresses issue #14200 requirements: moves LTO and strip to a config-based profile in .cargo/config.toml, updates wasm-opt flags to -Oz with required feature enables, and restores speed-oriented native builds (opt-level=3).
Out of Scope Changes check	✅ Passed	All changes are in scope: workspace profile adjustments, new WASM-specific config file, and WASM Cargo.toml updates directly support the stated goal of fixing optimizer flag application without removing features.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch jans-cedarling-14200

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[coderabbitai]

Actionable comments posted: 2

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@jans-cedarling/bindings/cedarling_wasm/.cargo/config.toml`:
- Around line 20-24: Update the top-of-file comment in
bindings/cedarling_wasm/.cargo/config.toml (lines referencing the profile
behavior) to remove the stale claim that the workspace sets opt-level = 3 and
instead state that Cargo overlays .cargo/config.toml onto the workspace profile
and this file sets opt-level = "z" for the release profile; also mention that
debug-assertions and overflow-checks are inherited from the workspace Cargo.toml
and that wasm-pack build --release uses Cargo’s profile handling so the local
.cargo/config.toml will be honored when building from this directory.

In `@jans-cedarling/Cargo.toml`:
- Around line 36-43: The comment notes a mismatch between the prose and the
actual [profile.release] keys: add an explicit opt-level entry to the release
profile to make native behavior unambiguous. Update the [profile.release] block
in Cargo.toml by adding opt-level = 3 (or alternatively revise the surrounding
comment to refer to Cargo’s default opt-level) so that the release profile in
this file explicitly documents the optimization level rather than implying it.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: ASSERTIVE

Plan: Pro

Run ID: b35cacda-9ffc-4bc8-a495-a1ad154e679a

📥 Commits

Reviewing files that changed from the base of the PR and between cf125e2 and 1d761a3.

📒 Files selected for processing (3)

• jans-cedarling/Cargo.toml
• jans-cedarling/bindings/cedarling_wasm/.cargo/config.toml
• jans-cedarling/bindings/cedarling_wasm/Cargo.toml