💥 Remove remoteConfigurationId from RUM SDK (breaking change, v7)

docs/plans/2026-03-03-init-user-global-context-design.md

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+# Design: Initial User and Global Context via `RumInitConfiguration`
+
+**Date:** 2026-03-03
+**Author:** Adrian de la Rosa
+**Branch:** `adlrb/ssi-breaking`
+**Status:** Approved
+
+## Problem
+
+The `@datadog/browser-remote-config` schema defines `rum.user` (`ContextItem[]`) and `rum.context` (`ContextItem[]`) fields that carry dynamic key-value pairs for populating user context and global context at SDK init time. These fields are embedded verbatim in bundles generated by `@datadog/browser-sdk-endpoint`, but `validateAndBuildRumConfiguration` in `rum-core` does not recognize them — they are silently dropped. `resolveDynamicValues` is never called, and `setUser`/`setGlobalContextProperty` are never invoked.
+
+## Decision
+
+Extend `RumInitConfiguration` with two new optional fields:
+
+- `user?: User` — applied via the user context manager after `startRum()`, equivalent to calling `datadogRum.setUser()` at init time
+- `globalContext?: Context` — applied via the global context manager after `startRum()`, equivalent to calling `datadogRum.setGlobalContextProperty()` for each key
+
+The bundle generator (`generateCombinedBundle`) resolves `DynamicOption` values from `user[]` and `context[]` arrays at browser runtime using inlined vanilla JS helpers, then passes the resolved plain objects to `DD_RUM.init()` as `user` and `globalContext`.
+
+## Architecture
+
+### rum-core changes
+
+**`packages/rum-core/src/domain/configuration/configuration.ts`**
+
+Add to `RumInitConfiguration`:
+```typescript
+user?: User
+globalContext?: Context
+```
+
+These types already exist in the RUM public API (`setUser` accepts `User`, `setGlobalContextProperty` accepts `Context`). No new shapes.
+
+**`packages/rum-core/src/boot/rumPublicApi.ts`**
+
+In `doStartRum` (the callback passed to `createPreStartStrategy`), after `startRum()` returns, check `cachedInitConfiguration` for `user` and `globalContext` and apply them through the returned context managers:
+
+```typescript
+if (cachedInitConfiguration.user) {
+  startRumResult.userContextManager.setContext(cachedInitConfiguration.user)
+}
+if (cachedInitConfiguration.globalContext) {
+  Object.entries(cachedInitConfiguration.globalContext).forEach(([key, value]) => {
+    startRumResult.globalContextManager.setContextProperty(key, value)
+  })
+}
+```
+
+This runs after the context managers are initialized but before any views are tracked, so the first view event carries the correct user and global context.
+
+### endpoint changes
+
+**`packages/endpoint/src/bundleGenerator.ts`**
+
+`generateCombinedBundle` no longer passes the raw `RumRemoteConfiguration` object directly to `DD_RUM.init()`. Instead it emits:
+
+1. Inline resolution helpers (`__dd_resolveContextValue`, `__dd_getCookie`, `__dd_resolveJsPath`, `__dd_resolveDom`) — vanilla ES5, namespaced to avoid collisions, covering all four `DynamicOption` strategies plus regex `extractor` support.
+
+2. Resolution loop that builds `user` and `globalContext` plain objects from the `ContextItem[]` arrays.
+
+3. A single `DD_RUM.init()` call with a spread of the scalar remote config fields plus the resolved `user` and `globalContext`:
+
+```js
+var __dd_user = {};
+(__DATADOG_REMOTE_CONFIG__.user || []).forEach(function(item) {
+  __dd_user[item.key] = __dd_resolveContextValue(item.value);
+});
+
+var __dd_ctx = {};
+(__DATADOG_REMOTE_CONFIG__.context || []).forEach(function(item) {
+  __dd_ctx[item.key] = __dd_resolveContextValue(item.value);
+});
+
+window.DD_RUM.init(Object.assign({}, __DATADOG_REMOTE_CONFIG__, {
+  user: Object.keys(__dd_user).length ? __dd_user : undefined,
+  globalContext: Object.keys(__dd_ctx).length ? __dd_ctx : undefined,
+}));
+```
+
+The resolution helpers are defined in a separate source file `packages/endpoint/src/contextResolutionHelpers.ts` that exports the JS string constant, keeping `bundleGenerator.ts` readable and allowing the helpers to be unit-tested independently.
+
+## Data Flow
+
+```
+Remote config JSON (server)
+  └── fetchRemoteConfiguration()          [Node.js, build time]
+      └── RumRemoteConfiguration
+          ├── scalar fields (sessionSampleRate, service, ...)
+          ├── user: ContextItem[]          [DynamicOption values — unresolved]
+          └── context: ContextItem[]       [DynamicOption values — unresolved]
+
+generateCombinedBundle()                  [Node.js, build time]
+  └── Embeds raw config as __DATADOG_REMOTE_CONFIG__
+  └── Emits resolution helpers + loop
+  └── Emits DD_RUM.init({ ...scalars, user: __dd_user, globalContext: __dd_ctx })
+
+Browser loads generated bundle            [runtime]
+  1. __dd_resolveContextValue resolves each DynamicOption
+     (reads cookies, walks window.*, queries DOM)
+  2. DD_RUM.init({ user: { id: "resolved", ... }, globalContext: { plan: "pro" } })
+  3. rum-core's doStartRum applies user/globalContext via context managers
+  4. First view event carries correct user context and global context
+```
+
+## Non-Goals
+
+- No changes to `setUser()` or `setGlobalContextProperty()` public API
+- No new dependencies between `rum-core` and `@datadog/browser-remote-config`
+- The `localStorage` strategy gap (exists in types, missing handler in `resolveDynamicOption`) is out of scope for this change
+
+## Testing
+
+### Unit tests
+
+- `packages/rum-core/src/boot/rumPublicApi.spec.ts` — verify that `user` and `globalContext` in `initConfiguration` are applied to context managers after start; verify they are ignored gracefully if absent or empty
+- `packages/endpoint/src/contextResolutionHelpers.spec.ts` — verify the emitted JS string resolves cookie/js/dom/string strategies correctly (run in jsdom)
+- `packages/endpoint/src/bundleGenerator.spec.ts` — verify the generated bundle includes resolution code when `user`/`context` are present; verify correct `DD_RUM.init()` shape in generated output
+
+### E2E tests
+
+- `test/e2e/scenario/rum/embeddedConfig.scenario.ts` — add cases for static user context and global context applied from embedded config
+- `test/e2e/scenario/rum/embeddedConfigDynamic.scenario.ts` — add cases for cookie and JS-path dynamic user context resolved correctly at page load