Fixed an issue with UpdateFromQuery/Async for string literals

[PabloFerroDev]

When we want to update some value, for example using this:

await db.Users
     .Where(o => o.Id == requestAccount.Id)
     .UpdateFromQueryAsync(o => new Users { 
         Name = name,
         Surname = surname,
         Email = email,
         Initials = initials,
         Job = job,
         Password = newPassword,
         LastPasswordUpdate = DateTime.UtcNow
     });
     

and the e-mail is something like 'luciano.cravero@testmail.com', the 'o.' part is replaced to [Extent1], producing an update that does not respect the original string.

[NorthernLight1]

Review of PR #164 - Fix UpdateFromQuery/Async string literal corruption

Fixes: Issue #165

Root Cause

The old code performed a naive string.Replace on the entire generated SQL expression, replacing the lambda parameter prefix (e.g. o.) with the table alias prefix (e.g. [Extent1].). This incorrectly mutated content inside SQL string literals - e.g. 'luciano.cravero@testmail.com' became 'lucian[Extent1].cravero@testmail.com'.

Fix Assessment

Core change in LinqExtensions.cs:

The new ReplaceOutsideSqlStringLiterals method uses a compiled regex ('(?:''|[^'])*') to split the SQL expression. Because the regex uses a capturing group, Regex.Split interleaves non-literal and literal segments [non-lit, lit, non-lit, ...]. Stepping i += 2 correctly applies the replacement only to non-literal segments.

Correctness checks:

• Regex correctly matches SQL string literals including escaped single quotes ('')
• Split interleaving behavior is correct for .NET's Regex.Split with capturing groups
• Static + compiled regex is efficient for a potentially hot path
• Unused using System.Threading.Tasks correctly removed and replaced with using System.Text.RegularExpressions

Tests

• With_String_Containing_Dot - directly reproduces the reported bug
• With_String_Column_Copy - regression guard ensuring column-reference expressions (where the dot must still be replaced) continue to work
• Both sync and async variants covered

Minor Suggestion (non-blocking)

Consider adding a brief comment to ReplaceOutsideSqlStringLiterals explaining that Regex.Split with a capturing group interleaves captured/non-captured segments, making the i += 2 step non-obvious to future maintainers.

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Verdict: Approved. The fix is minimal, targeted, and correct. Solid test coverage.