[Clippy] Modernise random/guid usage, fix discarded Guid bug, and remove dead code

[github-actions]

🤖 This is an automated PR from Clippy, an AI assistant for this repository.

Summary

Four focused code-quality improvements across the library:

1. Random.Shared instead of new Random() (DocumentBuilder.cs)

GenStyleIdFromStyleName was calling (new Random()).Next(990). This allocates a new Random instance on every call and can produce identical sequences when called in rapid succession on older runtimes. Using Random.Shared is the idiomatic .NET 6+ approach: no allocation, thread-safe, and backed by a properly seeded shared instance.

2. Fix discarded Guid.NewGuid() result — latent bug (WmlComparer.Private.Methods.ProduceDocument.cs)

Two Select lambdas in the text-box ancestor-unid processing contained:

if (thisUnid == null)
    Guid.NewGuid().ToString().Replace("-", "");  // result discarded!
return thisUnid;  // still null

The assignment to thisUnid was accidentally dropped, so null would be returned and inserted into the AncestorUnids array — potentially causing downstream NullReferenceExceptions or incorrect comparison results. Fixed to thisUnid = Guid.NewGuid().ToString("N");.

3. Simplify Guid.ToString("N") (WmlComparer.Private.Methods.Util.cs)

Guid.NewGuid().ToString().Replace("-", "") → Guid.NewGuid().ToString("N"). The "N" format specifier produces the same 32-character lowercase hex string without hyphens, but avoids the extra string allocation from Replace.

4. Remove #if false dead code (FieldRetriever.cs)

The original non-caching implementation of InstrText was left behind a #if false block with a comment noting the caching version is "significantly faster". This block has been dead code for a long time and can be safely removed.

Test Status

• Build: ✅ 0 errors
• Tests: ✅ 1699 passed, 1 skipped (pre-existing), 0 failed

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[Copilot]

Pull request overview

Modernizes random/GUID generation patterns in Clippit’s Word-processing utilities and comparer pipeline, fixes a latent bug where generated GUIDs were discarded, and removes long-dead conditional code.

Changes:

• Use Random.Shared in DocumentBuilder to avoid per-call Random allocations and weak seeding behavior.
• Replace Guid.NewGuid().ToString().Replace("-", "") with Guid.NewGuid().ToString("N") for lower-allocation GUID formatting.
• Fix two lambdas in comparer document production where a newly generated GUID was previously discarded, allowing null ancestor IDs to leak.
• Remove #if false dead code in FieldRetriever.InstrText.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

File	Description
Clippit/Word/DocumentBuilder.cs	Switch style-id suffix generation to Random.Shared.
Clippit/FieldRetriever.cs	Remove dead #if false non-caching implementation block.
Clippit/Comparer/WmlComparer.Private.Methods.Util.cs	Use Guid.ToString("N") for part URI name generation.
Clippit/Comparer/WmlComparer.Private.Methods.ProduceDocument.cs	Fix discarded GUID result when ancestor Unid is missing.

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[sergey-tihon]

@copilot fix inline comments

[Copilot]

@copilot fix inline comments

Fixed in commit 19d3cf2. Both lambdas now call ae.SetAttributeValue(PtOpenXml.Unid, thisUnid) immediately after generating the GUID, so repeated appearances of the same ancestor XElement get a consistent stable ID across all atoms.

[Copilot]

Pull request overview

Copilot reviewed 4 out of 4 changed files in this pull request and generated no new comments.

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