Fix crashes on saving scores with parts

[miiizen]

Resolves: #33516

This PR makes EIDRegister and EID::newUnique thread safe, as during saving we create and register new EIDs.
I have also made sure MasterScore::checkMidiMapping is only called for the master score. There's no need to repeat this for each part.

The crashes were introduced in #32702

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro

Run ID: 36ebb6d6-2c2e-49de-818f-17aa58520609

📥 Commits

Reviewing files that changed from the base of the PR and between acc3f9a and 331b6bb.

📒 Files selected for processing (6)

• muse
• src/engraving/infrastructure/eid.cpp
• src/engraving/infrastructure/eidregister.cpp
• src/engraving/infrastructure/eidregister.h
• src/engraving/rw/write/writer.cpp
• src/engraving/rw/write/writer.h

🚧 Files skipped from review as they are similar to previous changes (4)

• src/engraving/rw/write/writer.cpp
• src/engraving/infrastructure/eid.cpp
• muse
• src/engraving/infrastructure/eidregister.h

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📝 Walkthrough

Walkthrough

This PR advances the muse submodule and makes several concurrency-related changes: EID::newUnique() uses thread-local RNG and distribution; EIDRegister adds a mutable std::shared_mutex and takes a std::lock_guard in registerItemEID; Writer replaces GlobalInject with GlobalThreadSafeInject for IApplication and runs masterScore()->checkMidiMapping() only when score->isMaster().

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and accurately describes the main problem being fixed: preventing crashes when saving scores with parts.
Description check	✅ Passed	The description includes the issue link, explains the root cause (thread safety), and identifies the regression source, meeting most template requirements.
Linked Issues check	✅ Passed	Code changes directly address the linked issue #33516 by making EIDRegister and EID::newUnique thread-safe to prevent crashes during concurrent save operations with parts.
Out of Scope Changes check	✅ Passed	All changes are directly scoped to fixing thread-safety issues and save logic for the reported crash; the muse submodule update may warrant verification but appears scope-related.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[coderabbitai]

Actionable comments posted: 1

🤖 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 `@src/engraving/infrastructure/eidregister.cpp`:
- Line 43: The methods accessing the shared maps are inconsistently
synchronized: add appropriate locking around all accesses to m_itemToEid and
m_eidToItem—use an exclusive lock (std::lock_guard or std::unique_lock on
m_mutex) at the start of removeItem (since it modifies both maps) and use shared
locks (std::shared_lock on m_mutex) at the start of itemFromEID and EIDFromItem
(since they only read); ensure the locks are acquired before any map access in
the functions registerItemEID, removeItem, itemFromEID, and EIDFromItem to
prevent data races.

🪄 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: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro

Run ID: 858bb581-22f9-43bc-aca7-4cb8a773a10c

📥 Commits

Reviewing files that changed from the base of the PR and between 37b61ae and ec4ac8c.

📒 Files selected for processing (6)

• muse
• src/engraving/infrastructure/eid.cpp
• src/engraving/infrastructure/eidregister.cpp
• src/engraving/infrastructure/eidregister.h
• src/engraving/rw/write/writer.cpp
• src/engraving/rw/write/writer.h

[coderabbitai]

Actionable comments posted: 0

[davidstephengrant]

@miiizen I am no longer seeing assertions printed to the terminal, but this is still sometimes crashing upon save.

See here (crash at 00:34):

Screencast.from.2026-05-29.10-24-56.webm