Validate Golden

Validate an export against Unity golden values

Golden validation diffs the database this tool exports from a .snap against reference numbers captured from Unity's own Memory Profiler for the same snapshot. A pass means the export agrees with what a developer sees in the profiler; a failure names the exact metric and the expected/actual values.

Full reference (schema, every compared metric, tolerances, failure formats): docs/golden-validation.md. Read it before changing what validation compares. This skill is the operational quick-path.

Paths below are relative to the repo root (the directory containing MemorySnapshotDataTools.sln).

When to use

• Validate / verify an export, or confirm the tool matches Unity's Memory Profiler.
• Produce a golden file in Unity, or interpret a *_golden.json / *_validation_result.json.
• Debug a validation failure, or change what the comparison covers (also touch the Unity extractor).

The three steps

The golden file and the database must come from the same .snap or everything mismatches.

1. Extract golden values in Unity (produces {name}_golden.json)

The extractor is a Unity Editor package — com.unity.memory-snapshot-data-tools in UnityPackage/ (Unity 2022.3+, com.unity.memoryprofiler 1.1.12), not the .NET CLI. Import it into the target Unity project via a local file: path in that project's Packages/manifest.json, then run Tools → Memory Snapshot Validation → Extract Golden Values and pick a .snap. It writes {name}_golden.json next to the snapshot. It pulls the Summary-page numbers from the Memory Profiler's own model builders, so golden == what the profiler UI shows.

2. Export the same snapshot

dotnet run --project Cli/MemorySnapshotDataTools.Cli.csproj -- export <name>.snap <name>.duckdb --validate minimal

DuckDB recommended (.db + --destination sqlite also works). Needs the native_objects, native_roots, and summary_metrics tables — a current-schema export has them.

3. Run validate

dotnet run --project Cli/MemorySnapshotDataTools.Cli.csproj -- validate <name>_golden.json <name>.duckdb [--out result.json]

• Writes {name}_golden_validation_result.json next to the golden file unless --out is set, and prints the result to stdout.
• Exit codes: 0 = passed, 1 = metric mismatch(es), 3 = error (bad input / unparseable golden / unsupported DB extension). The DB is schema-gated first; an older major schema is rejected — re-export rather than upgrade (upgrade only covers minor analysis-view changes).

What it compares (summary — details in the doc)

• Native types: AssetBundle (from native_objects) and SerializedFile (from native_roots, area_name LIKE '%serializedfile%') — Count and AllocatedBytes exact, ResidentBytes within tolerance.
• PMR: sum of PersistentManager Remapper roots — Allocated exact, Resident within tolerance.
• Summary page: Totals + AllocatedMemoryDistribution + ManagedHeapUtilization rows from the summary_metrics table.

Tolerances: counts & allocated bytes must be exact; resident = max(64 KB, 1%); summary committed = max(64 KB, 1%), except estimated rows (Graphics, Untracked — golden ResidentAvailable=false) which get max(1 MB, 5%). Summary comparison is skipped when the golden file has no Summary rows (older/partial golden files still validate on native metrics).

Reading a failure

Each Failures[] entry is \<metric\>: expected=…, actual=…, e.g. SerializedFile.Count: expected=34, actual=33 or Summary[AllocatedMemoryDistribution].Native.Committed: expected=…, actual=…. A … row missing from export means the export lacks a Summary row the golden file has → re-export with the current tool. Everything mismatching → golden and DB came from different snapshots.

Changing what validation compares

Touch both sides so they don't drift:

• Tool: SQL constants in Core/Validation/GoldenValidationQueries.cs, comparison/tolerances in Core/Validation/GoldenValidationRunner.cs, models in Core/Validation/GoldenValidationModels.cs.
• Unity extractor: UnityPackage/com.unity.memory-snapshot-data-tools/Editor/GoldenValueExtractor.cs and shared names in …/Editor/MemorySnapshotValidationHelpers.cs.
• Validation SQL must stay constant-only (no interpolated external values) per docs/sql-safety.md.
• Add/extend tests in Tests/GoldenValidationRunnerTests.cs (they build a SQLite DB + golden JSON in temp and assert pass/fail). Test helpers must be public.
• Run dotnet test MemorySnapshotDataTools.sln and update docs/golden-validation.md.