Add IsDeadlockError

[Giorgi]

No description provided.

[Copilot]

Pull request overview

This PR adds deadlock detection to the exception-classification pipeline by introducing an IsDeadlockError classifier hook, mapping provider-specific deadlock signals to a new DeadlockException, and adding cross-provider tests to validate the behavior.

Changes:

• Add IsDeadlockError to IDbExceptionClassifier and implement it for SQLite, SQL Server, PostgreSQL, Oracle, and MySQL.
• Introduce DeadlockException and wire deadlock classification through the interceptor/factory.
• Add/override deadlock-focused tests and enable creating secondary DemoContext instances from stored options.

Reviewed changes

Copilot reviewed 13 out of 13 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
EntityFramework.Exceptions/Tests/SqliteTests.cs	Adds a SQLite-specific deadlock test case.
EntityFramework.Exceptions/Tests/OracleTests.cs	Adds an Oracle-specific deadlock test case with Oracle-specific rollback handling.
EntityFramework.Exceptions/Tests/DemoContext.cs	Stores DbContextOptions for creating secondary contexts in tests.
EntityFramework.Exceptions/Tests/DatabaseTests.cs	Adds a provider-agnostic deadlock test (overridden by some providers).
EntityFramework.Exceptions/Common/Exceptions.cs	Adds DeadlockException type.
EntityFramework.Exceptions/Common/ExceptionProcessorInterceptor.cs	Adds deadlock classification path and enum value.
EntityFramework.Exceptions/Common/ExceptionFactory.cs	Maps DatabaseError.DeadLock to DeadlockException.
DbExceptionClassifier/Sqlite/SqliteExceptionClassifier.cs	Implements SQLite deadlock detection.
DbExceptionClassifier/SqlServer/SqlServerExceptionClassifier.cs	Implements SQL Server deadlock detection (1205).
DbExceptionClassifier/PostgreSQL/PostgreSQLExceptionClassifier.cs	Implements PostgreSQL deadlock detection (DeadlockDetected).
DbExceptionClassifier/Oracle/OracleExceptionClassifier.cs	Implements Oracle deadlock detection (ORA-00060).
DbExceptionClassifier/MySQL/MySQLExceptionClassifier.cs	Implements MySQL deadlock detection.
DbExceptionClassifier/Common/IDbExceptionClassifier.cs	Adds IsDeadlockError to the classifier interface.

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[Copilot]

BeginTransactionAsync() on DemoContext doesn’t acquire a lock in SQLite until a statement is executed. As written, transaction1 is never used, so the controlContext update may succeed and the test will fail/flap. Execute at least one read/write statement inside transaction1 (and keep it uncommitted) before running the conflicting controlContext ExecuteUpdateAsync, or use an explicit locking transaction mode to reliably trigger SQLITE_LOCKED_SHAREDCACHE.

Suggested change

	// Execute a write operation within transaction1 to acquire a SQLite lock
	await DemoContext.Products
	.Where(c => c.Id == product.Id)
	.ExecuteUpdateAsync(c => c.SetProperty(p => p.Name, "Test11"));

[Copilot]

Adding IsDeadlockError as a new abstract interface member is a source/binary breaking change for any external IDbExceptionClassifier implementations. If this package is meant to be extensible, consider providing a default interface implementation returning false (net8 supports DIMs) to preserve compatibility, or ensure the package versioning reflects a breaking change.

Suggested change

	public bool IsDeadlockError(DbException exception);
	public bool IsDeadlockError(DbException exception) => false;