Migration
32 bites tagged Migration — interview questions with model answers, and 60-second explainers.
What do the spec file and CodeGen do in migration?
The spec file declares the component's typed props and events; CodeGen reads it at build time to generate type-safe C++/native and JS glue, catching mismatches early. migration mechanics.
Decommission a depended-on API gracefully
Map consumers and usage, provide a migration target, announce a versioned timeline, decommission only after traffic hits zero. graceful API deprecation with live consumers. shutting off the API with no replacement.
Build the case to deprecate a legacy feature
Quantify cost versus value and who the 2% are, propose migration paths and a phased sunset, weigh velocity against trust. data-driven deprecation with empathy. killing it abruptly on raw usage with no migration.
Automating a breaking design token rename
Ship a codemod to rewrite old token references, add a deprecation alias mapping old to new during a transition window, document the change. Token migration automation.
Deprecating a widely used component gracefully
Announce and document replacement, soft-deprecate with runtime and type warnings, ship codemods, remove only in a later major. Phased deprecation strategy.
Challenges of breaking changes in a design system
Technical (semver, codemods, coexistence) and organizational (comms, migration support, timelines) challenges. managing breaking changes at scale. shipping a breaking major with no migration path or warning.
Coexisting major versions during migration
Scoped aliases or namespaced packages, isolated token scopes, and incremental migration. running two breaking versions side by side safely. ignoring duplicated CSS, global token collisions, and bundle bloat.
Quantifying migration cost for a major release
Pre-release, scan codebases for affected usages and estimate engineer-hours; post-release, track actual upgrade lead time and effort. Whether you can estimate and measure migration effort.
Designing a component deprecation process
Announce with a replacement and timeline, mark deprecated with runtime and lint warnings, provide codemods, then remove only in a major release. Whether you can retire a component without breaking consumers.
Zero-downtime schema migration on a hot table
Expand-migrate-contract phases, dual-write and backfill, decouple deploys from migrations. safe online schema evolution. a single blocking ALTER plus drop-old-column in one release, breaking running code.
Near-zero-downtime database migration to cloud
Assess and provision, do a full load then continuous CDC replication with a tool like DMS, validate, then cut over with a rollback plan. planning a low-downtime migration. a one-shot dump-and-restore with a long outage.
Driving and measuring design system adoption
Lower friction with migration paths and great docs, incentivize over mandate, and measure adoption via package usage, component coverage, and code analysis. Strategy plus instrumentation for adoption.
Releasing a breaking Button change with SemVer
Bump the major version, write a changelog and migration guide, deprecate before removing where possible, and communicate clearly. Handling breaking changes responsibly under SemVer.
Structuring release notes for breaking API changes
Lead with a summary and why, group breaking changes with before/after migration steps, give deprecation timelines and an upgrade path. communicating breaking changes. burying breaking changes in a flat changelog.
Strangler Fig with serverless and an event bus
API Gateway acts as the routing facade, new features run as Lambda functions, an event bus decouples and fans out to new services, and traffic shifts feature by feature until the monolith… applying incremental migration with serverless.
Explain the Strangler Fig pattern
A facade routes traffic, new services gradually replace legacy features one slice at a time, and the old system is retired when fully strangled. incremental modernization strategy.
Migrating a stateful monolith to PaaS
Externalize state to backing services, make processes stateless and disposable, read config from the environment per Twelve-Factor. cloud-native refactoring strategy. a lift-and-shift that keeps local-disk state.
End-to-end process for a Modal props API break
Justify and design the change, additive rollout with deprecation, major release plus codemod, comms and adoption tracking. the full lifecycle of a breaking API change.
Gradual design system adoption in legacy code
Coexistence strategy, codemods for mechanical swaps, lint rules to block regressions, prioritize high-traffic surfaces. incremental migration of a large legacy codebase.
Technical and comms plan for a Button break
Additive-first then deprecate, major semver, codemod and guide, multi-channel early comms with adoption tracking. pairing technical migration tooling with communication.
Critical a11y fix requiring a breaking API change
Ship a safe interim fix, plan the breaking API as a major with deprecation and codemod, communicate urgency. balancing urgent accessibility risk against breaking-change discipline.
Rolling out a breaking change to a shared Button
Major semver bump, deprecation period, codemod and migration guide, staged comms. managing a breaking change in a high-blast-radius component. forcing an immediate hard cutover with no deprecation window or upgrade tooling.
Unify Android EventBus and RxJava with Kotlin Flow
Mixing EventBus, RxJava, and Kotlin Flow in Android codebases creates memory leaks and GC pressure from stream wrapping. Operator translation and lifecycle mismatches drive engineering debt.
Angular 21.1 ships with Signal Forms debounce patterns
Angular 21.1 ships with minor fixes. Signal Forms tutorials now show debounced async validators to cut wasted backend API calls. Migration guides for the modern Control Flow syntax are available for apps still on legacy structural directives.
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