Brandon Lucas
26d340b5a3
Better source change detection using find instead of single file check. Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
84 lines
3.0 KiB
Plaintext
84 lines
3.0 KiB
Plaintext
// Schema Evolution Demo
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// Demonstrates version tracking and automatic migrations
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// ============================================================
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// PART 1: Type-Declared Migrations
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// ============================================================
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// Define a versioned type with a migration from v1 to v2
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type User @v2 {
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name: String,
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email: String,
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// Migration from v1: add default email
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from @v1 = { name: old.name, email: "unknown@example.com" }
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}
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// Create a v1 user
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let v1_user = Schema.versioned("User", 1, { name: "Alice" })
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let v1_version = Schema.getVersion(v1_user) // 1
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// Migrate to v2 - uses the declared migration automatically
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let v2_user = Schema.migrate(v1_user, 2)
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let v2_version = Schema.getVersion(v2_user) // 2
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// ============================================================
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// PART 2: Runtime Schema Operations (separate type)
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// ============================================================
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// Create versioned values for a different type (no migration)
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let config1 = Schema.versioned("Config", 1, "debug")
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let config2 = Schema.versioned("Config", 2, "release")
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// Check versions
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let c1 = Schema.getVersion(config1) // 1
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let c2 = Schema.getVersion(config2) // 2
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// Migrate config (auto-migration since no explicit migration defined)
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let upgradedConfig = Schema.migrate(config1, 2)
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let upgradedConfigVersion = Schema.getVersion(upgradedConfig) // 2
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// ============================================================
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// PART 2: Practical Example - API Versioning
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// ============================================================
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// Simulate different API response versions
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fn createResponseV1(data: String): { version: Int, payload: String } =
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{ version: 1, payload: data }
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fn createResponseV2(data: String, timestamp: Int): { version: Int, payload: String, meta: { ts: Int } } =
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{ version: 2, payload: data, meta: { ts: timestamp } }
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// Version-aware processing
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fn getPayload(response: { version: Int, payload: String }): String =
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response.payload
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let resp1 = createResponseV1("Hello")
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let resp2 = createResponseV2("World", 1234567890)
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let payload1 = getPayload(resp1)
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let payload2 = resp2.payload
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// ============================================================
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// RESULTS
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// ============================================================
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fn main(): Unit with {Console} = {
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Console.print("=== Schema Evolution Demo ===")
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Console.print("")
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Console.print("Part 1: Type-declared migrations")
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Console.print(" User before migration: v" + toString(v1_version))
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Console.print(" User after migration: v" + toString(v2_version))
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Console.print("")
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Console.print("Part 2: Runtime schema operations")
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Console.print(" Config v1 version: " + toString(c1))
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Console.print(" Config v2 version: " + toString(c2))
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Console.print(" After upgrade: " + toString(upgradedConfigVersion))
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Console.print("")
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Console.print("Part 3: API versioning")
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Console.print(" Response v1 payload: " + payload1)
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Console.print(" Response v2 payload: " + payload2)
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}
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let output = run main() with {}
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