Improvements and clean up related to thorough golangci-lint checking

.github/workflows/zizmor.yml

@@ -21,4 +21,4 @@ jobs:
           persist-credentials: false
 
       - name: Run zizmor 🌈
-        uses: zizmorcore/zizmor-action@b1d7e1fb5de872772f31590499237e7cce841e8e # v0.5.3
+        uses: zizmorcore/zizmor-action@3dc1ecc9bcb9e94e9b2c709687979e1298497054 # v0.6.2

.gitignore

@@ -1,8 +1,5 @@
 # Ignorables.
 
-# Docs
-docs/_build
-
 # IDEs
 .idea
 

.golangci.yml

@@ -25,6 +25,11 @@ linters:
     - unparam
     - unused
     - whitespace
+  settings:
+    goconst:
+      # Repeated literals in tests are idiomatic and are excluded from
+      # reporting below, so they should not inflate counts for real code either.
+      ignore-tests: true
   exclusions:
     generated: lax
     presets:
@@ -33,8 +38,12 @@ linters:
       - legacy
       - std-error-handling
     rules:
+      # Repeated literals in table-driven tests are idiomatic, and long test
+      # tables are not complexity debt, so goconst/gocognit are not useful here.
       - linters:
           - bodyclose
+          - gocognit
+          - goconst
           - gosec
           - noctx
           - unparam

Makefile

@@ -56,10 +56,20 @@ gocyclo:
 	@ go install github.com/fzipp/gocyclo/cmd/gocyclo@latest
 	gocyclo -over 25 -avg -ignore "vendor" .
 
+# Mirrors the Lint step in .github/workflows/build_and_test.yml. Deliberately
+# not part of `test` while pre-existing complexity findings are outstanding;
+# CI runs it with continue-on-error for the same reason.
+lint:
+	@ command -v golangci-lint >/dev/null 2>&1 || { \
+		echo "golangci-lint not found. Install it: https://golangci-lint.run/docs/welcome/install/"; \
+		exit 1; \
+	}
+	golangci-lint run
+
 test: fmtcheck staticcheck vet
 	go test ./*.go $(TESTARGS)
 
 version:
 	@echo $(VERSION)
 
-.PHONY: clean test fmtcheck staticcheck vet gocyclo version testdeps cross build_dir default install
+.PHONY: clean test fmtcheck staticcheck vet lint gocyclo version testdeps cross build_dir default install