*: merge master to feature/active-active

.github/skills/tidb-test-guidelines/SKILL.md

@@ -24,6 +24,8 @@ description: Decide where to place TiDB tests and how to write them (basic struc
 - If a test must use multiple sessions or domains (for example, cross-session cache behavior), keep the extra stores/testkits but document why in the test.
 - Keep per-test runtime short; consolidate similar checks only if runtime stays reasonable.
 - Use behavior-based test names; never use issue-id-only names.
+- In test code, use the variable name `tk` for `*testkit.TestKit` (avoid `testKit`).
+- When merging multiple tests into one, keep a single `store` and a single `tk` unless multi-session behavior is required; do not create a new store/tk inside the same test body without a documented reason.
 
 ## Placement rules
 
@@ -38,9 +40,11 @@ description: Decide where to place TiDB tests and how to write them (basic struc
 
 - Apply the same rules (placement, shard_count, naming) to other packages beyond `pkg/planner`.
 - Use existing testdata patterns (`*_in.json`, `*_out.json`, `*_xut.json`) in the same directory when extending suites. When tests use testdata, run with `-record --tags=intest` as needed.
+- For `pkg/planner/core/casetest/rule` predicate pushdown cases, keep SQL in `predicate_pushdown_suite_in.json` and record both `EXPLAIN format='brief'` and query results via the test runner (see `rule_predicate_pushdown_test.go`).
 - When moving benchmarks between packages, update any `TestBenchDaily` wrappers that list them and keep `Makefile` `bench-daily` entries aligned with the new package location.
 - When updating tests in any `pkg/*` package, ask AI to update the corresponding case map under `references/`.
 - When updating tests in any other directory, also update this skill: add or extend a case map under `references/` and add guidance in this `SKILL.md` so future changes stay consistent.
+- When merging issue regression tests into existing behavior tests, keep the issue id in SQL comments (e.g. `/* issue:12345 */`) or nearby comments for traceability.
 - Prefer unit tests over `tests/integrationtest` for end-to-end coverage unless you need to avoid union-storage executor differences or require full workflow validation.
 - When tests read source files under Bazel, use `go/runfiles` and ensure the target file is exported via `exports_files()` in its owning `BUILD.bazel`.
 - For Bazel runfiles, be ready to include the workspace prefix (from `TEST_WORKSPACE`) in the runfile path if needed.

.github/skills/tidb-test-guidelines/references/planner-case-map.md

@@ -120,11 +120,10 @@
 ## pkg/planner/core/casetest
 
 ### Tests
-- `pkg/planner/core/casetest/integration_test.go` - planner/core/casetest: Cascades integration cases for verbose explain outputs, TiFlash isolation/MPP/partition behaviors, fix-control regressions, and issue-specific plan checks.
+- `pkg/planner/core/casetest/integration_test.go` - planner/core/casetest: Cascades integration cases for verbose explain outputs, TiFlash isolation/MPP/partition behaviors, fix-control regressions, and merged issue regressions.
 - `pkg/planner/core/casetest/main_test.go` - Configures default goleak settings and registers testdata.
-- `pkg/planner/core/casetest/plan_test.go` - planner/core/casetest: Tests prefer range scan and normalized plan output.
+- `pkg/planner/core/casetest/plan_test.go` - planner/core/casetest: Tests plan digest stability, normalized plan output, and related regressions.
 - `pkg/planner/core/casetest/stats_test.go` - planner/core/casetest: Tests group NDVs.
-- `pkg/planner/core/casetest/tiflash_predicate_push_down_test.go` - planner/core/casetest: Tests TiFlash late materialization and inverted index plans.
 
 ### Testdata
 - `pkg/planner/core/casetest/testdata/integration_suite_in.json`
@@ -167,7 +166,7 @@
 ## pkg/planner/core/casetest/cbotest
 
 ### Tests
-- `pkg/planner/core/casetest/cbotest/cbo_test.go` - planner/core/casetest/cbotest: Tests CBO regressions, no-analyze stats, and straight join cases.
+- `pkg/planner/core/casetest/cbotest/cbo_test.go` - planner/core/casetest/cbotest: Tests CBO analyze suites, no-analyze stats, straight join cases, and merged issue regressions.
 - `pkg/planner/core/casetest/cbotest/main_test.go` - Configures default goleak settings and registers testdata.
 
 ### Testdata
@@ -293,7 +292,7 @@
 ## pkg/planner/core/casetest/join
 
 ### Tests
-- `pkg/planner/core/casetest/join/join_test.go` - planner/core/casetest/join: Tests semijoin order, NULL-safe join EQ, join condition simplification, join key preservation, and issue regressions.
+- `pkg/planner/core/casetest/join/join_test.go` - planner/core/casetest/join: Tests semijoin order, NULL-safe join EQ, join condition simplification, join key preservation, and merged issue regressions.
 - `pkg/planner/core/casetest/join/main_test.go` - Configures default goleak settings and registers testdata.
 
 ## pkg/planner/core/casetest/logicalplan
@@ -306,7 +305,7 @@
 
 ### Tests
 - `pkg/planner/core/casetest/mpp/main_test.go` - Configures default goleak settings and registers testdata.
-- `pkg/planner/core/casetest/mpp/mpp_test.go` - planner/core/casetest/mpp: Tests MPP joins (broadcast/shuffle), exchange pruning, fine-grained join/agg, pushdown rules, versioning, and issue regressions.
+- `pkg/planner/core/casetest/mpp/mpp_test.go` - planner/core/casetest/mpp: Tests MPP joins (broadcast/shuffle), exchange pruning, join/agg pushdown, versioning, and merged issue regressions.
 
 ### Testdata
 - `pkg/planner/core/casetest/mpp/testdata/integration_suite_in.json`
@@ -324,7 +323,7 @@
 ### Tests
 - `pkg/planner/core/casetest/partition/integration_partition_test.go` - planner/core/casetest/partition: Tests list/list-columns pruning and dynamic/static plan differences.
 - `pkg/planner/core/casetest/partition/main_test.go` - Configures default goleak settings and registers testdata.
-- `pkg/planner/core/casetest/partition/partition_pruner_test.go` - planner/core/casetest/partition: Tests hash/list partition pruning and partition info extraction.
+- `pkg/planner/core/casetest/partition/partition_pruner_test.go` - planner/core/casetest/partition: Tests partition pruning rules, extract functions, and merged issue regressions.
 
 ### Testdata
 - `pkg/planner/core/casetest/partition/testdata/integration_partition_suite_in.json`
@@ -338,7 +337,7 @@
 
 ### Tests
 - `pkg/planner/core/casetest/physicalplantest/main_test.go` - Configures default goleak settings and registers testdata.
-- `pkg/planner/core/casetest/physicalplantest/physical_plan_test.go` - planner/core/casetest/physicalplantest: Tests refine/agg eliminator with plan suite data.
+- `pkg/planner/core/casetest/physicalplantest/physical_plan_test.go` - planner/core/casetest/physicalplantest: Tests plan suite cases, MPP hints, agg elimination, and merged issue regressions.
 
 ### Testdata
 - `pkg/planner/core/casetest/physicalplantest/testdata/cascades_template_in.json`
@@ -358,7 +357,7 @@
 - `pkg/planner/core/casetest/plancache/plan_cache_rebuild_test.go` - planner/core/casetest/plancache: Tests cached-plan clone/rebuild correctness and fast point get cloning.
 - `pkg/planner/core/casetest/plancache/plan_cache_suite_test.go` - planner/core/casetest/plancache: Tests prepared/non-prepared plan cache regressions, bindings, MV index, and resource groups.
 - `pkg/planner/core/casetest/plancache/plan_cache_test.go` - planner/core/casetest/plancache: Tests deallocate prepare cache separation and cache key benchmarks.
-- `pkg/planner/core/casetest/plancache/plan_cacheable_checker_test.go` - planner/core/casetest/plancache: Tests cacheable checks, IN-list fix control, and issue regressions.
+- `pkg/planner/core/casetest/plancache/plan_cacheable_checker_test.go` - planner/core/casetest/plancache: Tests cacheable checks, IN-list fix control, and merged issue regressions.
 
 ### Testdata
 - `pkg/planner/core/casetest/plancache/testdata/plan_cache_suite_in.json`
@@ -396,9 +395,9 @@
 - `pkg/planner/core/casetest/rule/rule_eliminate_projection_test.go` - planner/core/casetest/rule: Tests projection elimination with expression indexes.
 - `pkg/planner/core/casetest/rule/rule_inject_extra_projection_test.go` - planner/core/casetest/rule: Tests cast injection for aggregate function modes.
 - `pkg/planner/core/casetest/rule/rule_join_reorder_test.go` - planner/core/casetest/rule: Tests join reorder hints, hash-join toggle, and TiFlash/dynamic partitions.
-- `pkg/planner/core/casetest/rule/rule_outer2inner_test.go` - planner/core/casetest/rule: Tests outer-to-inner rewrites with regressions.
+- `pkg/planner/core/casetest/rule/rule_outer2inner_test.go` - planner/core/casetest/rule: Tests outer-to-inner rewrites with merged issue regressions.
 - `pkg/planner/core/casetest/rule/rule_outer_to_semi_join_test.go` - planner/core/casetest/rule: Tests outer-to-semi join rewrite correctness.
-- `pkg/planner/core/casetest/rule/rule_predicate_pushdown_test.go` - planner/core/casetest/rule: Tests predicate pushdown cases with collation-sensitive constants.
+- `pkg/planner/core/casetest/rule/rule_predicate_pushdown_test.go` - planner/core/casetest/rule: Tests predicate pushdown cases and records plan+result for selected cases.
 - `pkg/planner/core/casetest/rule/rule_predicate_simplification_test.go` - planner/core/casetest/rule: Tests predicate simplification across complex schemas.
 
 ### Testdata
@@ -477,7 +476,7 @@
 ### Tests
 - `pkg/planner/core/casetest/windows/main_test.go` - Configures default goleak settings and registers testdata.
 - `pkg/planner/core/casetest/windows/widow_with_exist_subquery_test.go` - planner/core/casetest/windows: Tests window functions with correlated EXISTS subqueries.
-- `pkg/planner/core/casetest/windows/window_push_down_test.go` - planner/core/casetest/windows: Tests TiFlash window pushdown plans and warnings.
+- `pkg/planner/core/casetest/windows/window_push_down_test.go` - planner/core/casetest/windows: Tests TiFlash window pushdown plans, warnings, and merged issue regressions.
 
 ### Testdata
 - `pkg/planner/core/casetest/windows/testdata/window_push_down_suite_in.json`

.gitignore

@@ -1,56 +1,80 @@
+# OS / filesystem
 __MACOSX
-bin
-/tidb-server/tidb-server
-/tidb-server/debug
-coverage.out
+.DS_Store
+
+# Editor / IDE
 .idea/
 *.iml
+.ijwb/
+.vscode
 *.swp
-*.log
-*.test.bin
 tags
-profile.coverprofile
-mysql_tester
-tests/integrationtest/integration-test.out
-tests/integrationtest/integrationtest_tidb-server
-tests/integrationtest/s/
-tests/integrationtest/replayer/
-*.fail.go
+
+# Local tooling metadata
+.specstory
+.cursor
+.codex
+.trae
+
+# Go workspace / tooling
+go.work
+go.work.sum
+.golangci.bck.yml
+
+# Binaries / generated tools
+bin
+/tidb-server/tidb-server
+/tidb-server/debug
 tools/bin/
-vendor
+mysql_tester
+genkeyword
 /_tools/
-.DS_Store
-.vscode
-bench_daily.json
-coverage.txt
-var
-fix.sql
-export-20*/
-*-coverage.xml
-*-junit-report.xml
-compose-dev.yaml
-# Files generated when testing
-out
+
+# Dependencies
+vendor
+
+# Bazel
+# skywalking-eyes 0.4 cannot handle the git glob syntax correctly. As a temporary workaround,
+# we explicitly list the bazel-related files and directories to be ignored.
+# TODO: test and consider upgrading skywalking-eyes in the future.
 /_bazel
+bazel-*
 bazel-bin
 bazel-out
 bazel-testlogs
 bazel-tidb
 MODULE.bazel.lock
-.ijwb/
-/oom_record/
-*.log.json
-genkeyword
+
+# Testing / coverage / reports
+# Files generated when testing
+out
 test_coverage
+coverage.out
+coverage.txt
 coverage.dat
-.specstory
-.golangci.bck.yml
-go.work
-go.work.sum
-.cursor
-.codex
+profile.coverprofile
+*-coverage.xml
+*-junit-report.xml
+*.test.bin
+*.fail.go
+*.log
+*.log.json
 *__failpoint_stash__
+/oom_record/
+
+# Integration tests
+tests/integrationtest/integration-test.out
+tests/integrationtest/integrationtest_tidb-server
+tests/integrationtest/s/
+tests/integrationtest/replayer/
+
+# Local dev artifacts
+bench_daily.json
+compose-dev.yaml
+fix.sql
+export-20*/
+var
+
 # Personal config files
 /*config.toml
 .cache
-.trae

AGENTS.md

@@ -49,6 +49,13 @@ This file provides guidance to agents when working with code in this repository.
 
 - When creating new source files (for example: `*.go`), include the standard TiDB copyright (and Apache 2.0 license) header at the top; copy the header from an existing file in the same directory and update the year if needed.
 
+### Notes
+
+- Notes directory: `docs/note/<component>/` is the canonical location for component notes. If missing, create it and add an entry here.
+- Notes rules: update existing sections when topics overlap; append new sections only for new topics. Purpose: capture decisions, pitfalls, and test patterns.
+- Planner rule notes: `docs/note/planner/rule/rule_ai_notes.md`.
+- If a single notes file exceeds 2000 lines, split by functionality into multiple markdown files and update references here.
+
 ## Building
 
 ### Bazel bootstrap (`make bazel_prepare`)
@@ -68,7 +75,7 @@ Recommended local build flow:
 make bazel_prepare
 
 # build
-make
+make bazel_bin
 
 # optional: regenerate generated code if needed
 make gogenerate
@@ -136,6 +143,13 @@ The following points must be achieved:
 2. Existing tests should be reused as much as possible, and existing test data and table structures should be utilized. Modifications should be made on this basis to accommodate the new tests.
 3. Some tests use the JSON files in `testdata` as the test set (`xxxx_in.json`) and the validation set (`xxxx_out.json` and `xxxx_xut.json`). It is necessary to modify the test set before running the unit test.
 
+#### Regression tests for bug fixes
+
+- A bug fix should include a regression test that reproduces the issue.
+- Verify the new/updated test fails on the buggy code (before the fix), and passes after the fix.
+  - Example approaches: run the test on `upstream/master` (or the target base commit) before applying the fix, or temporarily revert the fix and confirm the test fails.
+- Include the exact test command in the PR description under `Tests` (for example: `go test -run TestXxx --tags=intest ./pkg/...`).
+
 ### Integration Tests
 
 Integration tests are located in the `/tests/integrationtest` directory.
@@ -249,6 +263,17 @@ curl -f "http://${PD_ADDR}/pd/api/v1/version"
 - **Environment check**: Check for running playground processes before starting.
 - **Fmt-only changes**: If PR only involves code formatting (gofmt, indentation), do NOT run time-consuming `realtikvtest`. Just ensure local compilation passes.
 
+## Issue Instructions
+
+- When submitting an issue, follow the GitHub templates under `.github/ISSUE_TEMPLATE/` and fill in all required fields.
+- Bug reports should include minimal reproduction steps, expected/actual behavior, and the TiDB version (for example: the output of `SELECT tidb_version()`).
+- Search existing issues/PRs first to avoid duplicates (try `gh` first; for example: `gh search issues --repo pingcap/tidb --include-prs "<keywords>"`), and include any relevant logs/configuration/SQL plans to help diagnosis.
+- Apply labels to help triage:
+  - `type/*` is usually applied by the issue template; add `type/regression` when applicable.
+  - Add at least one `component/*` label (for example: `component/ddl`, `component/br`, `component/parser`).
+  - For bug/regression issues, `severity/*` and affected-version label(s) are required (for example: `affects-8.5`; use `may-affects-*` if unsure).
+  - If you don't have permission to add labels, include a `Suggested labels: ...` line in the issue body.
+
 ## Pull Request Instructions
 
 ### PR title