build: update golangci-lint to v2.12.2 with commit-pinned installs

Pin golangci-lint to commit c0d3ddc9cf3faa61a4e378e879ece580256d76e5
(v2.12.2) in Dockerfile and script/bootstrap. Fix the goconst findings
the new version reports under the unchanged canonical .golangci.yml by
extracting shared test fixture constants and a statusError constant in
the watcher.

.dockerignore

@@ -1,6 +1,5 @@
 .git/
 bin/
-.lint-cache/
 *.md
 LICENSE
 .editorconfig

.gitignore

@@ -1,7 +1,6 @@
 bin/
 vendor/
 data/
-.lint-cache/
 .env
 *.exe
 /dnswatcher

.golangci.yml

@@ -1,9 +1,5 @@
 version: "2"
 
-# Config schema uses the golangci-lint v2 layout (settings live under
-# linters.settings, not top-level linters-settings) so that the
-# thresholds below are actually applied by golangci-lint >= v2.
-
 run:
   timeout: 5m
   modules-download-mode: readonly
@@ -18,7 +14,8 @@ linters:
     - wsl              # Deprecated, replaced by wsl_v5
     - wrapcheck        # Too verbose for internal packages
     - varnamelen       # Short names like db, id are idiomatic Go
-  settings:
+
+linters-settings:
   lll:
     line-length: 88
   funlen:
@@ -30,5 +27,6 @@ linters:
     threshold: 100
 
 issues:
+  exclude-use-default: false
   max-issues-per-linter: 0
   max-same-issues: 0

README.md

@@ -17,26 +17,6 @@ without requiring an external database.
 
 ---
 
-## No DNS mocking. Ever.
-
-**DNS is never mocked in this project — not in tests, not anywhere else.**
-No mock resolvers, no fake DNS servers, no stubbed lookups.
-
-dnswatcher's entire purpose is correct behavior against the real DNS.
-Tests exercise real iterative resolution against live nameservers by
-design; a test suite that passes against a mock proves nothing about the
-one thing this program exists to do.
-
-When live tests are flaky, that is a robustness problem, and it gets
-fixed with robustness: retries with backoff, querying multiple
-independent nameservers, longer timeouts — or explicit opt-in gating
-decided by the project owner. Never with mocks.
-
-Contributions that introduce mocked, faked, or stubbed DNS will be
-rejected.
-
----
-
 ## Features
 
 ### DNS Domain Monitoring (Apex Domains)
@@ -387,10 +367,7 @@ them. We provide:
 - `script/projectname` — print the project name (used for the Docker
   image tag)
 - `script/test` — run the test suite (race detector, coverage)
-- `script/lint` — run golangci-lint, with its cache and its lock file
-  isolated to this checkout (under the git-ignored `.lint-cache/`) so
-  concurrent checkouts on one host cannot share cache entries or
-  contend on a single lock
+- `script/lint` — run golangci-lint
 - `script/fmt` — format all code (gofmt -s, goimports)
 - `script/fmt-check` — check formatting (read-only)
 - `script/check` — run test, lint, and fmt-check

TODO.md

@@ -25,23 +25,9 @@ confirm make check still passes.
 
 # Completed Steps
 
-- 2026-08-09: `script/lint` now isolates golangci-lint's per-user global
-  state to the checkout (#121): `GOLANGCI_LINT_CACHE` and `TMPDIR` are
-  both pointed at the git-ignored, Docker-ignored `.lint-cache/`. The
-  cache fixes cross-contamination; `TMPDIR` is what moves the lock,
-  which lives at `$TMPDIR/golangci-lint.lock` and not in the cache
-  directory. Reproduced both failure modes on the unfixed script (10 of
-  12 concurrent runs void with `parallel golangci-lint is running`; 11
-  of 12 reporting another checkout's paths) and both are gone at 20-way
-  concurrency after the fix
 - 2026-08-07: golangci-lint bumped to v2.12.2 (commit-pinned installs
-  in `Dockerfile` and `script/bootstrap`); `.golangci.yml` set to the
-  org-standard v2-schema config used across the org's repos
-  (owner-authorized; same file is being landed as canonical via prompts
-  PR #24), with settings under `linters.settings` so the
-  lll/funlen/cyclop/dupl thresholds apply; fixed the resulting
-  `goconst`, `dupl`, and `lll` findings; the informational `gomodguard`
-  deprecation warning under this config is accepted
+  in `Dockerfile` and `script/bootstrap`); fixed the resulting
+  `goconst` findings. `.golangci.yml` unchanged (canonical)
 - 2026-07-07 Adopted scripts-to-rule-them-all: `script/` entrypoints,
   Makefile shims, README Entrypoints section
 - 2026-02-20: iterative DNS resolver implemented; tests made hermetic

internal/config/classify_test.go

@@ -17,33 +17,13 @@ func TestClassifyDNSName(t *testing.T) {
 	}{
 		{name: "apex domain simple", input: "example.com", want: config.DNSNameTypeDomain},
 		{name: "hostname simple", input: "www.example.com", want: config.DNSNameTypeHostname},
-		{
-			name:  "apex domain multi-part TLD",
-			input: "example.co.uk",
-			want:  config.DNSNameTypeDomain,
-		},
-		{
-			name:  "hostname multi-part TLD",
-			input: "api.example.co.uk",
-			want:  config.DNSNameTypeHostname,
-		},
+		{name: "apex domain multi-part TLD", input: "example.co.uk", want: config.DNSNameTypeDomain},
+		{name: "hostname multi-part TLD", input: "api.example.co.uk", want: config.DNSNameTypeHostname},
 		{name: "public suffix itself", input: "co.uk", wantErr: true},
 		{name: "empty string", input: "", wantErr: true},
-		{
-			name:  "deeply nested hostname",
-			input: "a.b.c.example.com",
-			want:  config.DNSNameTypeHostname,
-		},
-		{
-			name:  "trailing dot stripped",
-			input: "example.com.",
-			want:  config.DNSNameTypeDomain,
-		},
-		{
-			name:  "uppercase normalized",
-			input: "WWW.Example.COM",
-			want:  config.DNSNameTypeHostname,
-		},
+		{name: "deeply nested hostname", input: "a.b.c.example.com", want: config.DNSNameTypeHostname},
+		{name: "trailing dot stripped", input: "example.com.", want: config.DNSNameTypeDomain},
+		{name: "uppercase normalized", input: "WWW.Example.COM", want: config.DNSNameTypeHostname},
 	}
 
 	for _, tt := range tests {

internal/notify/delivery_test.go

@@ -25,20 +25,18 @@ const (
 	colorDefault = "#6c757d"
 )
 
-// Priority strings used across multiple tests.
+// Priority and fixture values shared across tests.
 const (
 	prioError   = "error"
 	prioWarning = "warning"
-	prioSuccess = "success"
 	prioInfo    = "info"
+	prioSuccess = "success"
 	prioUnknown = "unknown"
-	prioDefault = "default"
-	prioUrgent  = "urgent"
+	ntfyUrgent  = "urgent"
+	ntfyDefault = "default"
+	testHost    = "example.com"
 )
 
-// testHost is the hostname used in request construction tests.
-const testHost = "example.com"
-
 // errSimulated is a static error for transport failures.
 var errSimulated = errors.New("simulated transport failure")
 
@@ -115,13 +113,13 @@ func TestNtfyPriority(t *testing.T) {
 		input string
 		want  string
 	}{
-		{prioError, prioUrgent},
+		{prioError, ntfyUrgent},
 		{prioWarning, "high"},
-		{prioSuccess, prioDefault},
+		{prioSuccess, ntfyDefault},
 		{prioInfo, "low"},
-		{"", prioDefault},
-		{prioUnknown, prioDefault},
-		{"critical", prioDefault},
+		{"", ntfyDefault},
+		{prioUnknown, ntfyDefault},
+		{"critical", ntfyDefault},
 	}
 
 	for _, tc := range cases {
@@ -303,10 +301,10 @@ func TestSendNtfyHeaders(t *testing.T) {
 		)
 	}
 
-	if captured.priority != prioUrgent {
+	if captured.priority != ntfyUrgent {
 		t.Errorf(
 			"Priority header = %q, want %q",
-			captured.priority, prioUrgent,
+			captured.priority, ntfyUrgent,
 		)
 	}
 
@@ -325,9 +323,9 @@ func TestSendNtfyAllPriorities(t *testing.T) {
 		input string
 		want  string
 	}{
-		{prioError, prioUrgent},
+		{prioError, ntfyUrgent},
 		{prioWarning, "high"},
-		{prioSuccess, prioDefault},
+		{prioSuccess, ntfyDefault},
 		{prioInfo, "low"},
 	}
 
@@ -370,69 +368,56 @@ func TestSendNtfyAllPriorities(t *testing.T) {
 	}
 }
 
-// assertSendStatusError verifies that send returns an error
-// wrapping wantErr when the server responds with status.
-func assertSendStatusError(
-	t *testing.T,
-	status int,
-	wantErr error,
-	send func(*notify.Service, *url.URL) error,
-) {
-	t.Helper()
+func TestSendNtfyClientError(t *testing.T) {
+	t.Parallel()
 
 	srv := httptest.NewServer(
 		http.HandlerFunc(
 			func(w http.ResponseWriter, _ *http.Request) {
-				w.WriteHeader(status)
+				w.WriteHeader(http.StatusForbidden)
 			}),
 	)
 	defer srv.Close()
 
 	svc := notify.NewTestService(srv.Client().Transport)
-	target, _ := url.Parse(srv.URL)
+	topicURL, _ := url.Parse(srv.URL)
 
-	err := send(svc, target)
+	err := svc.SendNtfy(
+		context.Background(), topicURL, "t", "m", "info",
+	)
 	if err == nil {
-		t.Fatalf("expected error for %d response", status)
+		t.Fatal("expected error for 403 response")
 	}
 
-	if !errors.Is(err, wantErr) {
-		t.Errorf("error = %v, want %v", err, wantErr)
+	if !errors.Is(err, notify.ErrNtfyFailed) {
+		t.Errorf("error = %v, want ErrNtfyFailed", err)
 	}
 }
 
-func sendNtfyInfo(
-	svc *notify.Service, target *url.URL,
-) error {
-	return svc.SendNtfy(
-		context.Background(), target, "t", "m", prioInfo,
-	)
-}
-
-func sendSlackInfo(
-	svc *notify.Service, target *url.URL,
-) error {
-	return svc.SendSlack(
-		context.Background(), target, "t", "m", prioInfo,
-	)
-}
-
-func TestSendNtfyClientError(t *testing.T) {
-	t.Parallel()
-
-	assertSendStatusError(
-		t, http.StatusForbidden,
-		notify.ErrNtfyFailed, sendNtfyInfo,
-	)
-}
-
 func TestSendNtfyServerError(t *testing.T) {
 	t.Parallel()
 
-	assertSendStatusError(
-		t, http.StatusInternalServerError,
-		notify.ErrNtfyFailed, sendNtfyInfo,
+	srv := httptest.NewServer(
+		http.HandlerFunc(
+			func(w http.ResponseWriter, _ *http.Request) {
+				w.WriteHeader(http.StatusInternalServerError)
+			}),
 	)
+	defer srv.Close()
+
+	svc := notify.NewTestService(srv.Client().Transport)
+	topicURL, _ := url.Parse(srv.URL)
+
+	err := svc.SendNtfy(
+		context.Background(), topicURL, "t", "m", "info",
+	)
+	if err == nil {
+		t.Fatal("expected error for 500 response")
+	}
+
+	if !errors.Is(err, notify.ErrNtfyFailed) {
+		t.Errorf("error = %v, want ErrNtfyFailed", err)
+	}
 }
 
 func TestSendNtfySuccess(t *testing.T) {
@@ -633,19 +618,53 @@ func TestSendSlackAllColors(t *testing.T) {
 func TestSendSlackClientError(t *testing.T) {
 	t.Parallel()
 
-	assertSendStatusError(
-		t, http.StatusBadRequest,
-		notify.ErrSlackFailed, sendSlackInfo,
+	srv := httptest.NewServer(
+		http.HandlerFunc(
+			func(w http.ResponseWriter, _ *http.Request) {
+				w.WriteHeader(http.StatusBadRequest)
+			}),
 	)
+	defer srv.Close()
+
+	svc := notify.NewTestService(srv.Client().Transport)
+	webhookURL, _ := url.Parse(srv.URL)
+
+	err := svc.SendSlack(
+		context.Background(), webhookURL, "t", "m", "info",
+	)
+	if err == nil {
+		t.Fatal("expected error for 400 response")
+	}
+
+	if !errors.Is(err, notify.ErrSlackFailed) {
+		t.Errorf("error = %v, want ErrSlackFailed", err)
+	}
 }
 
 func TestSendSlackServerError(t *testing.T) {
 	t.Parallel()
 
-	assertSendStatusError(
-		t, http.StatusBadGateway,
-		notify.ErrSlackFailed, sendSlackInfo,
+	srv := httptest.NewServer(
+		http.HandlerFunc(
+			func(w http.ResponseWriter, _ *http.Request) {
+				w.WriteHeader(http.StatusBadGateway)
+			}),
 	)
+	defer srv.Close()
+
+	svc := notify.NewTestService(srv.Client().Transport)
+	webhookURL, _ := url.Parse(srv.URL)
+
+	err := svc.SendSlack(
+		context.Background(), webhookURL, "t", "m", "error",
+	)
+	if err == nil {
+		t.Fatal("expected error for 502 response")
+	}
+
+	if !errors.Is(err, notify.ErrSlackFailed) {
+		t.Errorf("error = %v, want ErrSlackFailed", err)
+	}
 }
 
 func TestSendSlackNetworkError(t *testing.T) {
@@ -970,62 +989,74 @@ func TestSendNotificationMattermostOnly(t *testing.T) {
 	}
 }
 
-// assertSendNotificationTolerates verifies SendNotification
-// neither panics nor blocks when the endpoint configured by
-// setURL responds with status.
-func assertSendNotificationTolerates(
-	t *testing.T,
-	status int,
-	priority string,
-	setURL func(*notify.Service, *url.URL),
-) {
-	t.Helper()
+func TestSendNotificationNtfyError(t *testing.T) {
+	t.Parallel()
 
 	srv := httptest.NewServer(
 		http.HandlerFunc(
 			func(w http.ResponseWriter, _ *http.Request) {
-				w.WriteHeader(status)
+				w.WriteHeader(http.StatusInternalServerError)
 			}),
 	)
 	defer srv.Close()
 
-	target, _ := url.Parse(srv.URL)
+	ntfyURL, _ := url.Parse(srv.URL)
 
 	svc := notify.NewTestService(http.DefaultTransport)
-	setURL(svc, target)
+	svc.SetNtfyURL(ntfyURL)
 
+	// Should not panic or block.
 	svc.SendNotification(
-		context.Background(), "t", "m", priority,
+		context.Background(), "t", "m", "error",
 	)
 
 	time.Sleep(100 * time.Millisecond)
 }
 
-func TestSendNotificationNtfyError(t *testing.T) {
-	t.Parallel()
-
-	assertSendNotificationTolerates(
-		t, http.StatusInternalServerError, prioError,
-		(*notify.Service).SetNtfyURL,
-	)
-}
-
 func TestSendNotificationSlackError(t *testing.T) {
 	t.Parallel()
 
-	assertSendNotificationTolerates(
-		t, http.StatusForbidden, prioError,
-		(*notify.Service).SetSlackWebhookURL,
+	srv := httptest.NewServer(
+		http.HandlerFunc(
+			func(w http.ResponseWriter, _ *http.Request) {
+				w.WriteHeader(http.StatusForbidden)
+			}),
 	)
+	defer srv.Close()
+
+	slackURL, _ := url.Parse(srv.URL)
+
+	svc := notify.NewTestService(http.DefaultTransport)
+	svc.SetSlackWebhookURL(slackURL)
+
+	svc.SendNotification(
+		context.Background(), "t", "m", "error",
+	)
+
+	time.Sleep(100 * time.Millisecond)
 }
 
 func TestSendNotificationMattermostError(t *testing.T) {
 	t.Parallel()
 
-	assertSendNotificationTolerates(
-		t, http.StatusBadGateway, prioWarning,
-		(*notify.Service).SetMattermostWebhookURL,
+	srv := httptest.NewServer(
+		http.HandlerFunc(
+			func(w http.ResponseWriter, _ *http.Request) {
+				w.WriteHeader(http.StatusBadGateway)
+			}),
 	)
+	defer srv.Close()
+
+	mmURL, _ := url.Parse(srv.URL)
+
+	svc := notify.NewTestService(http.DefaultTransport)
+	svc.SetMattermostWebhookURL(mmURL)
+
+	svc.SendNotification(
+		context.Background(), "t", "m", "warning",
+	)
+
+	time.Sleep(100 * time.Millisecond)
 }
 
 // ── SlackPayload JSON marshaling ──────────────────────────

internal/notify/retry.go

@@ -69,7 +69,7 @@ func (rc RetryConfig) backoff(attempt int) time.Duration {
 	lo := raw * (1 - jitterFraction)
 	hi := raw * (1 + jitterFraction)
 
-	jittered := lo + rand.Float64()*(hi-lo) //nolint:gosec // jitter needs no crypto/rand
+	jittered := lo + rand.Float64()*(hi-lo) //nolint:gosec // jitter does not need crypto/rand
 
 	return time.Duration(jittered)
 }

internal/state/state_test.go

@@ -223,8 +223,7 @@ func TestSaveLoadRoundTrip_Ports(t *testing.T) {
 	}
 }
 
-// TestSaveLoadRoundTrip_Certificates verifies certificate data
-// survives a save/load cycle.
+// TestSaveLoadRoundTrip_Certificates verifies certificate data survives a save/load cycle.
 func TestSaveLoadRoundTrip_Certificates(t *testing.T) {
 	t.Parallel()
 
@@ -1073,8 +1072,7 @@ func TestConcurrentGetSet(t *testing.T) {
 	wg.Wait()
 }
 
-// runConcurrentOps performs a series of get/set/delete
-// operations for concurrency testing.
+// runConcurrentOps performs a series of get/set/delete operations for concurrency testing.
 func runConcurrentOps(s *state.State, key string, now time.Time) {
 	const iterations = 50
 

internal/watcher/watcher.go

@@ -26,11 +26,8 @@ const tlsPort = 443
 // hoursPerDay converts days to hours for duration calculations.
 const hoursPerDay = 24
 
-// Status values recorded for nameserver and certificate checks.
-const (
-	statusOK    = "ok"
-	statusError = "error"
-)
+// statusError is the status value recorded for failed checks.
+const statusError = "error"
 
 // Params contains dependencies for Watcher.
 type Params struct {
@@ -350,7 +347,7 @@ func buildHostnameState(
 	for ns, recs := range records {
 		hs.RecordsByNameserver[ns] = &state.NameserverRecordState{
 			Records:     recs,
-			Status:      statusOK,
+			Status:      "ok",
 			LastChecked: now,
 		}
 	}
@@ -408,7 +405,7 @@ func (w *Watcher) detectNSDisappearances(
 	current map[string]map[string][]string,
 ) {
 	for ns, prevNS := range prev.RecordsByNameserver {
-		if _, ok := current[ns]; ok || prevNS.Status != statusOK {
+		if _, ok := current[ns]; ok || prevNS.Status != "ok" {
 			continue
 		}
 
@@ -711,7 +708,7 @@ func (w *Watcher) handleTLSError(
 	now time.Time,
 	err error,
 ) {
-	if hasPrev && !w.firstRun && prev.Status == statusOK {
+	if hasPrev && !w.firstRun && prev.Status == "ok" {
 		msg := fmt.Sprintf(
 			"Host: %s\nIP: %s\nError: %s",
 			hostname, ip, err,
@@ -754,7 +751,7 @@ func (w *Watcher) handleTLSSuccess(
 			Issuer:                  cert.Issuer,
 			NotAfter:                cert.NotAfter,
 			SubjectAlternativeNames: cert.SubjectAlternativeNames,
-			Status:                  statusOK,
+			Status:                  "ok",
 			LastChecked:             now,
 		},
 	)

script/lint

@@ -1,40 +1,11 @@
 #!/bin/sh
 # script/lint: run the linter.
-#
-# golangci-lint keeps two pieces of per-user global state, and both of
-# them break when several checkouts on one host lint concurrently:
-#
-#   1. Its analysis cache (GOLANGCI_LINT_CACHE, default
-#      ~/.cache/golangci-lint). Entries are keyed by content, not by
-#      checkout, so a hit written by another checkout is replayed
-#      verbatim - including that checkout's file paths. The run then
-#      reports findings for files it never linted.
-#
-#   2. Its "one runner at a time" lock, which does NOT live in the
-#      cache directory: golangci-lint locks
-#      $(os.TempDir())/golangci-lint.lock, i.e.
-#      "$TMPDIR"/golangci-lint.lock (pkg/commands/run.go,
-#      acquireFileLock). It waits 5s, then aborts with "parallel
-#      golangci-lint is running" - a non-result that looks like a lint
-#      failure. Setting GOLANGCI_LINT_CACHE alone does not move it.
-#
-# So both are pinned under the checkout root. The cache is never shared,
-# and TMPDIR makes the lock file per-checkout, which keeps the lock
-# doing its actual job (serialising runs that share one cache) at the
-# right scope. .lint-cache/ is git-ignored and Docker-ignored, and
-# caching still works: it persists across runs in this checkout.
 set -eu
 
 ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
 
 main() {
     cd "$ROOT"
-
-    GOLANGCI_LINT_CACHE="$ROOT/.lint-cache/cache"
-    TMPDIR="$ROOT/.lint-cache/tmp"
-    export GOLANGCI_LINT_CACHE TMPDIR
-    mkdir -p "$GOLANGCI_LINT_CACHE" "$TMPDIR"
-
     golangci-lint run --config .golangci.yml ./...
 }