# PR 3319 conflict resolution plan

## Goal

Resolve the merge conflict between `feat/premium-dm-azure` and `master` for PR #3319 while preserving both:

- Azure Premium DM source support added by the PR
- upstream precheck/listing API additions already present on `master`

## Current context

| Item | Value |
|---|---|
| PR | `tidbcloud/dataflow-service#3319` |
| Head branch | `feat/premium-dm-azure` |
| Base branch | `master` |
| Mergeability | `CONFLICTING` / `DIRTY` |
| Worktree | `/home/tennix/workspace/worktrees/tidbcloud/dataflow-service/pr3319-conflict` |
| Observed conflicting file | `dataflow-service-ng/idl/pbgen/proto/premium_dm/v1beta2/premium_dm.pb.go` |

## Root cause analysis

The logical source file `dataflow-service-ng/idl/idl/dataflow/premium_dm/v1beta2/premium_dm.proto` can be merged cleanly because the two sides modify different semantic areas:

- PR branch adds `AZURE_FLEXIBLE_MYSQL = 2` to `PremiumDMSourceType`
- `master` adds `ListPremiumMigrationPrechecks` RPC and related messages

The actual merge conflict appears only in generated code:

- `dataflow-service-ng/idl/pbgen/proto/premium_dm/v1beta2/premium_dm.pb.go`

This is expected because the generated descriptor blob is a monolithic string and does not merge linewise.

## Symbols and behavior to preserve

| Source | Must preserve |
|---|---|
| PR branch | `PremiumDMSourceType_AZURE_FLEXIBLE_MYSQL` and related API/schema output |
| master | `ListPremiumMigrationPrechecks` RPC, request/response messages, generated outputs |

## Execution steps

1. Reproduce the merge against `master` in the task worktree.
   - Command: `git fetch origin master && git merge --no-commit --no-ff FETCH_HEAD`
   - Success criteria: merge stops with the expected generated-file conflict.
2. Confirm the only unresolved path is the generated `premium_dm.pb.go`.
   - Command: `git diff --name-only --diff-filter=U`
   - Success criteria: only the generated pb file is unresolved.
3. Keep the semantically merged `.proto` and regenerate outputs instead of hand-editing generated code.
   - Command: `git checkout --ours dataflow-service-ng/idl/pbgen/proto/premium_dm/v1beta2/premium_dm.pb.go`
   - Rationale: discard conflicted generated text, then rebuild from merged source of truth.
4. Regenerate IDL outputs.
   - Command: `make generate-idl`
   - Success criteria:
     - generated pb file contains `AZURE_FLEXIBLE_MYSQL`
     - generated outputs reflect `ListPremiumMigrationPrechecks`
     - no unresolved conflicts remain.
5. Stage the resolved/generated files.
   - Command: `git add dataflow-service-ng/idl/idl/dataflow/premium_dm/v1beta2/premium_dm.proto dataflow-service-ng/idl/pbgen/proto/premium_dm/v1beta2/premium_dm.pb.go dataflow-service-ng/api/premium_dm.swagger.json dataflow-service-ng/api/premium_dm.ui.swagger.json`
   - Success criteria: `git diff --name-only --diff-filter=U` returns empty.
6. Run verification focused on this conflict resolution.
   - Commands:
     - `git diff --name-only --diff-filter=U`
     - `git status --short`
     - `make generate-idl` (already doubles as generator validation)
   - Optional heavier validation if needed later: `make app-unit-test-local`

## Files expected to change

- `dataflow-service-ng/idl/idl/dataflow/premium_dm/v1beta2/premium_dm.proto`
- `dataflow-service-ng/idl/pbgen/proto/premium_dm/v1beta2/premium_dm.pb.go`
- `dataflow-service-ng/api/premium_dm.swagger.json`
- `dataflow-service-ng/api/premium_dm.ui.swagger.json`

## Risks

1. `make generate-idl` may touch unrelated generated files because `master` has broader changes in flight.
2. The repo already has many non-conflict merge changes from `master`; avoid claiming the branch is ready for merge without a final human check.
3. Running full unit tests may be expensive and may surface unrelated baseline failures.

## Verification summary target

At completion, verify all of the following:

- `git diff --name-only --diff-filter=U` is empty
- generated `premium_dm.pb.go` contains `AZURE_FLEXIBLE_MYSQL`
- merged proto retains `ListPremiumMigrationPrechecks`
- `make generate-idl` succeeds