[Experiment] Integrate scheduler readability stack with server main

.github/.golangci.yml

@@ -234,6 +234,10 @@ linters:
       - path: ^tools\/.+\.go
         linters:
           - revive
+      # These packages remain imported to read and maintain persisted HSM state.
+      - text: "SA1019: go.temporal.io/server/service/history/hsm/(callbacks|nexusoperations) is deprecated"
+        linters:
+          - staticcheck
 issues:
   max-issues-per-linter: 0
   max-same-issues: 0

.github/CODEOWNERS

@@ -13,6 +13,8 @@
 
 /chasm/lib/nexusoperation/ @temporalio/act @temporalio/nexus
 /chasm/lib/callback/ @temporalio/act @temporalio/nexus
+/chasm/lib/workflow/nexus_* @temporalio/act @temporalio/nexus
+/chasm/nexus_* @temporalio/oss-foundations @temporalio/act @temporalio/nexus
 
 # Service Clients
 
@@ -31,10 +33,11 @@
 
 /common/tasks/ @temporalio/oss-foundations @temporalio/cgs
 /common/persistence/ @temporalio/oss-foundations @temporalio/oss-matching @temporalio/cgs
+/common/persistence/**/nexus_endpoint* @temporalio/oss-foundations @temporalio/oss-matching @temporalio/nexus
 
-# Components
+# Legacy HSM implementations
 
-/components/ @temporalio/act @temporalio/nexus
+/service/history/hsm/ @temporalio/act @temporalio/nexus
 
 # Proto Definitions
 
@@ -51,6 +54,10 @@
 # DB Schema
 /schema/**/visibility/ @temporalio/oss-foundations
 
+# Frontend Service
+
+/service/frontend/nexus_* @temporalio/nexus
+
 # History Service
 
 /service/history/archival/ @temporalio/oss-foundations
@@ -82,7 +89,7 @@
 /service/worker/dlq/ @temporalio/oss-foundations
 
 /service/worker/scanner/ @temporalio/oss-foundations @temporalio/oss-matching
-/service/worker/scanner/executions/ @temporalio/oss-foundations 
+/service/worker/scanner/executions/ @temporalio/oss-foundations
 /service/worker/scanner/history/ @temporalio/oss-foundations
 /service/worker/scanner/build_ids/ @temporalio/oss-matching
 /service/worker/scanner/taskqueue/ @temporalio/oss-matching
@@ -100,3 +107,6 @@
 *_mock.go      @temporalio/server @temporalio/cgs @temporalio/nexus
 *_gen.go       @temporalio/server @temporalio/cgs @temporalio/nexus
 *.gen.go       @temporalio/server @temporalio/cgs @temporalio/nexus
+
+# This generated file has no code owner to allow automated updates by CI.
+/tests/testcore/shard_salt.txt

.github/actions/post-test-reporting/action.yml

@@ -64,15 +64,15 @@ runs:
 
     - name: Upload code coverage to Codecov
       if: ${{ !failure() && !cancelled() }}
-      uses: codecov/codecov-action@0fb7174895f61a3b6b78fc075e0cd60383518dac # v5.5.5
+      uses: codecov/codecov-action@e79a6962e0d4c0c17b229090214935d2e33f8354 # v6.0.1
       with:
         token: ${{ env.CODECOV_TOKEN }}
         directory: ./.testoutput
         flags: ${{ steps.codecov.outputs.flag }}
 
     - name: Upload test results to Codecov
       if: ${{ !cancelled() }}
-      uses: codecov/codecov-action@0fb7174895f61a3b6b78fc075e0cd60383518dac # v5.5.5
+      uses: codecov/codecov-action@e79a6962e0d4c0c17b229090214935d2e33f8354 # v6.0.1
       with:
         token: ${{ env.CODECOV_TOKEN }}
         directory: ./.testoutput

.github/copilot-instructions.md

@@ -13,26 +13,30 @@ Apply these patterns when reviewing PRs or suggesting code changes.
 - Remove redundant nil checks after you just set a value
 - Do not export anything that doesn't need to be exported
 
-## 2. Go Naming Conventions
+## 2. Go Conventions
 
 - Don't use `Get` prefix for getters: `func (a *Activity) Store()` not `GetStore()`
 - Don't use `Impl` suffix for implementations
 - Don't put underscore after `Test` in test names: `TestRetry` not `Test_Retry`
 - Avoid stuttering: don't use `ActivityStatus` in package `activity`, just `Status`
 - Use `ok` boolean pattern instead of nil checks where idiomatic
+- Prefer `cmp.Or` for defaults when zero means "unset"; it returns the first non-zero argument. Use an `if` statement for side-effecting or expensive fallbacks because all arguments are evaluated.
 
-## 3. Testify Suite Correctness and Reliability
+## 3. Testing Correctness and Reliability
 
 - Never use `s.T()` in subtests - use the subtest's `t` parameter
 - Never use suite assertion methods (`s.NoError`, `s.Equal`) from goroutines - causes panics
 - Use `EventuallyWithT` when you need assertions inside eventually blocks, and use that block's `t`
 - Use `require.ErrorAs(t, err, &specificErr)` for specific error type checks
 - Prefer `require` over `assert` - it's rarely useful to continue a test after a failed assertion
+- Prefer table-driven tests over separate `Test*` methods when cases exercise the same behavior. Give each case a descriptive name and run it as a subtest.
+- Run independent cases in parallel in plain `t.Run` tests. Testify suites do not support parallel subtests.
+- Prefer comparing a function's full result with an expected value over separate `require.Equal` calls for each field. Use `protorequire.ProtoEqual` for proto results and proto fields within non-proto results. Use other field-level assertions only when part of the result is relevant.
 - Add comments explaining why `Eventually` is needed (e.g., eventual consistency)
 - Do not use single-value type assertions on errors (`err.(*T)`); this panics instead of failing the test when the type doesn't match. Use `errors.As` with a guarded return.
 - When launching a goroutine to maintain a precondition for later assertions (e.g., keeping pollers active so a deployment version gets registered), loop until context cancellation rather than running once. A single attempt that times out exits silently, leaving downstream Eventually/propagation waits to hang until their own deadline.
 - Never call testify assertions (`s.NoError`, `s.Equal`, `require.NoError`, even `assert.NoError`) inside a `go func()` — if the goroutine outlives the test, the assertion panics the binary with `panic: Fail in goroutine after TestXxx has completed`. Move assertions to the test goroutine or use a buffered error channel.
-- Any `<-ch` that isn't inside a `select` with `ctx.Done()` will hang indefinitely if the sender never sends. Always provide a context cancellation fallback.
+- Prefer `await.Rcv` and `await.Snd` for blocking channel operations so tests fail on timeout instead of hanging indefinitely.
 - Never write to package-level or global variables in tests — parallel tests share the same process; thread values through function parameters instead.
 - Never use `time.Sleep` or `time.Since(start) > threshold` to enforce ordering — use channels, `sync.WaitGroup`, or `EventuallyWithT` instead.
 - When using `EventuallyWithT` (or similar) to wait for a condition driven by a background goroutine, ensure the goroutine's timeout is longer than the `EventuallyWithT` deadline — if the background op times out first, the condition will never be satisfied and the wait will hang until its own deadline.
@@ -62,12 +66,14 @@ Apply these patterns when reviewing PRs or suggesting code changes.
 
 - Follow existing patterns: "We have been passing through the frontend request in other libraries. Let's keep the same pattern here"
 - Use existing utilities before creating new ones
+- Use static logger messages and record all dynamic content in structured tags
 - Follow CLI documentation conventions (capitalize proper nouns)
 - Match existing metric tag formats (CONSTANT_CASE for enum values)
 - Use the same error message style (no punctuation for single sentences)
 
 ## 7. Code comments
 
+- Write comments that read like sentences as full sentences, starting with a capital letter and ending with punctuation. Short labels, end-of-line fragments, directives, and `TODO` markers are exempt.
 - A comment should be removed if the behavior of the code without the comment should be apparent to a reader familiar with the codebase.
 - If the benefit of a comment can be achieved by improving variable/function names then suggest that.
 - A comment must not give unnecessary or verbose explanation.

.github/workflows/claude-review-teams.yml

@@ -226,8 +226,8 @@ jobs:
       pull-requests: write
       issues: write
     steps:
-      - uses: actions/checkout@v4
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6.0.3
+      - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6.0.3
         with:
           ref: ${{ needs.check-review-eligibility.outputs.head_sha }}
           path: pr-head

.github/workflows/optimize-test-sharding.yml

@@ -8,6 +8,7 @@ on:
 
 permissions:
   contents: read
+  pull-requests: write
 
 env:
   SALT_FILE: tests/testcore/shard_salt.txt
@@ -51,8 +52,9 @@ jobs:
           GH_TOKEN: ${{ steps.generate-token.outputs.token }}
 
       - name: Create pull request
+        id: create-pr
         run: |
-          if git diff --quiet; then
+          if git diff --quiet -- "${{ env.SALT_FILE }}"; then
             echo "No changes to shard salt"
             exit 0
           fi
@@ -69,10 +71,24 @@ jobs:
           git commit -m "Update test shard salt"
           git push origin ${{ env.BRANCH }}
 
-          gh pr create \
+          pr_url=$(gh pr create \
             --title "Update test shard salt" \
-            --body "Automatically generated by the optimize-test-sharding workflow."
+            --body "Automatically generated by the optimize-test-sharding workflow.")
 
-          gh pr merge ${{ env.BRANCH }} --auto --squash
+          echo "pr_url=${pr_url}" >> "${GITHUB_OUTPUT}"
         env:
           GH_TOKEN: ${{ steps.generate-token.outputs.token }}
+
+      - name: Approve pull request
+        if: steps.create-pr.outputs.pr_url != ''
+        env:
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          PR_URL: ${{ steps.create-pr.outputs.pr_url }}
+        run: gh pr review --approve "${PR_URL}"
+
+      - name: Enable auto-merge
+        if: steps.create-pr.outputs.pr_url != ''
+        env:
+          GH_TOKEN: ${{ steps.generate-token.outputs.token }}
+          PR_URL: ${{ steps.create-pr.outputs.pr_url }}
+        run: gh pr merge "${PR_URL}" --auto --squash

.github/workflows/run-tests.yml

@@ -551,3 +551,36 @@ jobs:
           go run ./cmd/tools/ci-notify alert \
             --run-id "${{ github.run_id }}" \
             --slack-webhook "$SLACK_WEBHOOK"
+
+  notify-data-race:
+    name: Notify Slack on Data Race
+    # Runs on both passing and failing main runs: the race detector can trip on
+    # one attempt and pass on a retry, leaving the run green while a data race
+    # was still recorded in the test-summary artifacts.
+    if: |
+      always() &&
+      github.ref == 'refs/heads/main' &&
+      (needs.test-status.result == 'success' || needs.test-status.result == 'failure')
+    needs: test-status
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      actions: read
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6.0.3
+
+      - name: Set up Go
+        uses: actions/setup-go@4a3601121dd01d1626a1e23e37211e3254c1c06c # v6.4.0
+        with:
+          go-version-file: "go.mod"
+          cache: true
+
+      - name: Send Slack notification
+        env:
+          SLACK_WEBHOOK: ${{ secrets.SLACK_WEBHOOK }}
+          GH_TOKEN: ${{ github.token }}
+        run: |
+          go run ./cmd/tools/ci-notify data-race \
+            --run-id "${{ github.run_id }}" \
+            --slack-webhook "$SLACK_WEBHOOK"

.github/workflows/stale.yml

@@ -12,7 +12,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: label stale pull requests
-        uses: actions/stale@5bef64f19d7facfb25b37b414482c7164d639639 # v9.1.0
+        uses: actions/stale@3a9db7e6a41a89f618792c92c0e97cc736e1b13f # v10.0.0
         with:
           days-before-close: -1 # ie disabled
           days-before-stale: 120

AGENTS.md

@@ -47,7 +47,8 @@ Before starting the implementation of any request, you MUST REVIEW the following
 - `/service/worker`: worker service implementation
 
 ## Important Commands:
-- Linting: `make lint-code`
+- Fast Go linting (changed packages): `make lint-code-fast`
+- Full Go linting (all packages): `make lint-code`
 - Formatting imports: `make fmt-imports`
 - Code generation: `make proto`
 - Update API proto: `make update-go-api`
@@ -87,7 +88,7 @@ When requested to perform tasks like fixing bugs, adding features, refactoring,
 3. **Implement:** Use the available tools to act on the plan, strictly adhering to the project's established conventions (detailed under 'Core Mandates').
 4. **Regenerate:** If necessary, regenerate code based on your changes. If you alter anything annotated with `//go:generate` or in a `.proto` file you will need to do this.
 5. **Verify (Tests):** If applicable and feasible, verify the changes using the project's testing procedures. Identify the correct test commands and frameworks by examining 'README' files, build/package configuration (e.g., 'Makefile'), or existing test execution patterns. NEVER assume standard test commands.
-6. **Verify (Standards):** VERY IMPORTANT: After making code changes, execute the project-specific build, linting and type-checking commands (`make lint-code`)
+6. **Verify (Standards):** VERY IMPORTANT: After making code changes, execute the project-specific build, linting and type-checking commands (`make lint-code-fast` for development)
 
 ## Planning
 When planning (under 'Software Engineering Tasks'):

Makefile

@@ -172,11 +172,11 @@ $(STAMPDIR):
 $(LOCALBIN):
 	@mkdir -p $(LOCALBIN)
 
-# When updating the version, update the golangci-lint GHA workflow as well.
 .PHONY: golangci-lint
+LINT_CODE_TARGETS ?= ./...
 GOLANGCI_LINT_BASE_REV ?= $(MAIN_BRANCH)
 GOLANGCI_LINT_FIX ?= true
-GOLANGCI_LINT_VERSION := v2.9.0
+GOLANGCI_LINT_VERSION := v2.13.0
 GOLANGCI_LINT := $(LOCALBIN)/golangci-lint-$(GOLANGCI_LINT_VERSION)
 $(GOLANGCI_LINT): $(LOCALBIN)
 	$(call go-install-tool,$(GOLANGCI_LINT),github.com/golangci/golangci-lint/v2/cmd/golangci-lint,$(GOLANGCI_LINT_VERSION))
@@ -229,7 +229,7 @@ YAMLFMT := $(LOCALBIN)/yamlfmt-$(YAMLFMT_VER)
 $(YAMLFMT): | $(LOCALBIN)
 	$(call go-install-tool,$(YAMLFMT),github.com/google/yamlfmt/cmd/yamlfmt,$(YAMLFMT_VER))
 
-GOIMPORTS_VER := v0.36.0
+GOIMPORTS_VER := v0.49.0
 GOIMPORTS := $(LOCALBIN)/goimports-$(GOIMPORTS_VER)
 $(STAMPDIR)/goimports-$(GOIMPORTS_VER): | $(STAMPDIR) $(LOCALBIN)
 	$(call go-install-tool,$(GOIMPORTS),golang.org/x/tools/cmd/goimports,$(GOIMPORTS_VER))
@@ -263,7 +263,7 @@ $(STAMPDIR)/mockgen-$(MOCKGEN_VER): | $(STAMPDIR) $(LOCALBIN)
 	@touch $@
 $(MOCKGEN): $(STAMPDIR)/mockgen-$(MOCKGEN_VER)
 
-STRINGER_VER := v0.36.0
+STRINGER_VER := v0.49.0
 STRINGER := $(LOCALBIN)/stringer
 $(STAMPDIR)/stringer-$(STRINGER_VER): | $(STAMPDIR) $(LOCALBIN)
 	$(call go-install-tool,$(STRINGER),golang.org/x/tools/cmd/stringer,$(STRINGER_VER))
@@ -404,10 +404,36 @@ lint-actions: $(ACTIONLINT)
 	@printf $(COLOR) "Linting GitHub actions..."
 	@$(ACTIONLINT)
 
+.PHONY: lint-code lint-code-fast
+# --new-from-rev filters reported issues _after_ analysis; this target also reduces package inputs _before_ analysis.
+lint-code-fast:
+	@if ! git rev-parse --verify --quiet "$(GOLANGCI_LINT_BASE_REV)^{commit}" >/dev/null; then \
+		printf $(RED) "GOLANGCI_LINT_BASE_REV=$(GOLANGCI_LINT_BASE_REV) is not a known commit; fetch it or override GOLANGCI_LINT_BASE_REV"; \
+		exit 1; \
+	fi
+	@base=$$(git merge-base HEAD "$(GOLANGCI_LINT_BASE_REV)"); \
+	targets=$$({ \
+		git diff --no-renames --name-only "$$base" -- '*.go'; \
+		git ls-files --others --exclude-standard -- '*.go'; \
+	} | sed 's|^|./|; s|/[^/]*$$||' | sort -u \
+	  | while read -r dir; do [ -d "$$dir" ] && printf '%s ' "$$dir"; done); \
+	if [ -z "$$targets" ]; then \
+		printf $(COLOR) "No changed Go packages to lint."; \
+	else \
+		$(MAKE) GOLANGCI_LINT_BASE_REV="$$base" LINT_CODE_TARGETS="$$targets" lint-code; \
+	fi
+
 lint-code: $(GOLANGCI_LINT) $(ERRORTYPE)
 	@printf $(COLOR) "Linting code..."
-	@$(GOLANGCI_LINT) run --verbose --build-tags $(ALL_TEST_TAGS) --timeout 10m --fix=$(GOLANGCI_LINT_FIX) --new-from-rev=$(GOLANGCI_LINT_BASE_REV) --config=.github/.golangci.yml
-	@go vet -tags $(ALL_TEST_TAGS) -vettool="$(ERRORTYPE)" -style-check=false ./...
+	@$(GOLANGCI_LINT) run \
+		--verbose \
+		--build-tags $(ALL_TEST_TAGS) \
+		--timeout 10m \
+		--fix=$(GOLANGCI_LINT_FIX) \
+		--new-from-rev=$(GOLANGCI_LINT_BASE_REV) \
+		--config=.github/.golangci.yml \
+		$(LINT_CODE_TARGETS)
+	@go vet -tags $(ALL_TEST_TAGS) -vettool="$(ERRORTYPE)" -style-check=false $(LINT_CODE_TARGETS)
 
 lint-yaml: $(YAMLFMT)
 	@printf $(COLOR) "Checking YAML formatting..."