René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"[Order 05][P2] Harden duplicate detection and null binary materialization","articleBody":"## Priority order\n\nOrder: 05 of 09\nPriority: P2 correctness\n\n## Problem\n\nProvider error handling and binary materialization have fragile edge cases.\n\nEvidence:\n\n- `src/NEventStore.Persistence.Sql/SqlDialects/MySqlDialect.cs:43`\n- MySQL duplicate detection reflects a `Number` property and immediately casts it.\n- `src/NEventStore.Persistence.Sql/CommitExtensions.cs:87`\n- `GetByteArray` returns `[default]` for `null`/`DBNull.Value`.\n\n## Impact\n\n- MySQL can mask non-provider exceptions with `NullReferenceException` or invalid casts during error handling.\n- Nullable `Headers` values can be deserialized from one zero byte instead of returning default, which can fail for legacy rows or manually inserted rows.\n\n## Mandatory test-first workflow\n\n- Add tests first to reproduce or verify each behavior.\n- Add a unit test proving `MySqlDialect.IsDuplicate(new Exception(...))` returns false and does not throw.\n- Add a materialization test for a commit row with `Headers = NULL`.\n- Do not change production code until the tests capture the expected behavior.\n\n## Proposed action\n\n- Guard MySQL `IsDuplicate` for missing or non-int `Number`.\n- Prefer provider-specific exception checks where available.\n- Return `[]` for `null` and `DBNull.Value` in `GetByteArray`.\n\n## Acceptance criteria\n\n- Duplicate detection does not throw for unrelated exception types.\n- Null headers materialize as default/empty headers behavior without deserialization failure.\n- Existing duplicate-commit behavior remains covered.\n\nSource: `docs/Project-Analysis-Issue-Drafts.md`.","author":{"url":"https://github.com/AGiorgetti","@type":"Person","name":"AGiorgetti"},"datePublished":"2026-06-11T09:21:09.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":0},"url":"https://github.com/62/NEventStore.Persistence.SQL/issues/62"}