Feature: Daniel's tooling for local module replacements

.github/workflows/check-consistency.yml

@@ -0,0 +1,19 @@
+name: Check consistency
+
+on:
+  pull_request:
+  workflow_dispatch:
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Setup Go
+        uses: actions/setup-go@v4
+        with:
+          go-version: 1.21
+      - name: Build tooling
+        run: (cd tooling/go && go build ./cmd/local-overrides-enforcer)
+      - name: Check consistency
+        run: ./tooling/go/local-overrides-enforcer

.github/workflows/test-tooling.yml

@@ -0,0 +1,17 @@
+name: Test tooling
+
+on:
+  pull_request:
+  workflow_dispatch:
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Setup Go
+        uses: actions/setup-go@v4
+        with:
+          go-version: 1.21
+      - name: Run tooling tests
+        run: cd tooling/go && go test ./...

tooling/go/.gitignore

@@ -0,0 +1 @@
+/local-overrides-enforcer

tooling/go/cmd/local-overrides-enforcer/main.go

@@ -0,0 +1,74 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+	"io/fs"
+	"log"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"github.com/CodeYourFuture/curriculum/tooling/go/internal/local-overrides-enforcer/checker"
+)
+
+func main() {
+	var rootDirectory string
+	flag.StringVar(&rootDirectory, "root-dir", ".", "Root directory to search for go.mod files in")
+	excludeDirectoriesFlag := flag.String("exclude", filepath.Join("tooling", "go"), "Directories to exclude from searches (comma-delimited)")
+	var parentModule string
+	flag.StringVar(&parentModule, "parent-module", "github.com/CodeYourFuture/curriculum", "Parent module to search for missing overrides within")
+
+	flag.Parse()
+
+	var err error
+	rootDirectory, err = filepath.Abs(rootDirectory)
+	if err != nil {
+		log.Fatalf("Failed to get absolute path of root directory: %v", err)
+	}
+
+	var excludeDirectories []string
+	for _, excludeDirectory := range strings.Split(*excludeDirectoriesFlag, ",") {
+		excludeDirectory, err = filepath.Abs(excludeDirectory)
+		if err != nil {
+			log.Fatalf("Failed to get absolute path of exclude directory: %v", err)
+		}
+		excludeDirectories = append(excludeDirectories, excludeDirectory)
+	}
+
+	sawBadFile := false
+
+	err = filepath.WalkDir(rootDirectory, func(path string, d fs.DirEntry, err error) error {
+		for _, excluded := range excludeDirectories {
+			if path == excluded {
+				return fs.SkipDir
+			}
+		}
+		if err != nil {
+			return err
+		}
+
+		if d.Name() != "go.mod" {
+			return nil
+		}
+		content, err := os.ReadFile(path)
+		if err != nil {
+			return fmt.Errorf("failed to read %s: %w", path, err)
+		}
+		expectedContents, ok, err := checker.CheckFile(path, content, parentModule)
+		if err != nil {
+			return fmt.Errorf("failed to check %s: %w", path, err)
+		}
+		if !ok {
+			sawBadFile = true
+			fmt.Printf("⚠️  File at path %s didn't have some local overrides - its contents should be:\n%s\n", path, expectedContents)
+		}
+		return nil
+	})
+	if err != nil {
+		log.Fatalf("Error walking filesystem: %v", err)
+	}
+	if sawBadFile {
+		os.Exit(1)
+	}
+}

tooling/go/go.mod

@@ -0,0 +1,14 @@
+module github.com/CodeYourFuture/curriculum/tooling/go
+
+go 1.21.5
+
+require (
+	github.com/stretchr/testify v1.8.4
+	golang.org/x/mod v0.14.0
+)
+
+require (
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)

tooling/go/go.sum

@@ -0,0 +1,12 @@
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/testify v1.8.4 h1:CcVxjf3Q8PM0mHUKJCdn+eZZtm5yQwehR5yeSVQQcUk=
+github.com/stretchr/testify v1.8.4/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo=
+golang.org/x/mod v0.14.0 h1:dGoOF9QVLYng8IHTm7BAyWqCqSheQ5pYWGhzW00YJr0=
+golang.org/x/mod v0.14.0/go.mod h1:hTbmBsO62+eylJbnUtE2MGJUyE7QWk4xUqPFrRgJ+7c=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

tooling/go/internal/local-overrides-enforcer/checker/checker.go

@@ -0,0 +1,56 @@
+package checker
+
+import (
+	"fmt"
+	"strings"
+
+	"golang.org/x/mod/modfile"
+)
+
+// CheckFile checks that a go.mod file has local overrides for all children of the passed parent module.
+// It returns one of:
+//   - If the contents was correct: "", true, nil
+//   - If the contents was not correct: the expected contents, false, nil
+//   - If an error occurred: "", false, error
+func CheckFile(goModPath string, contents []byte, parentModule string) (string, bool, error) {
+	gomodFile, err := modfile.Parse(goModPath, contents, nil)
+	if err != nil {
+		return "", false, fmt.Errorf("failed to parse %s as go.mod file: %w", goModPath, err)
+	}
+
+	parentModuleWithTrailingSlash := parentModule + "/"
+
+	if !strings.HasPrefix(gomodFile.Module.Mod.Path, parentModuleWithTrailingSlash) {
+		return "", false, fmt.Errorf("module at path %s was named %s which isn't a child of %s", goModPath, gomodFile.Module.Mod.Path, parentModule)
+	}
+	slashCount := strings.Count(gomodFile.Module.Mod.Path[len(parentModule):], "/")
+
+	replaces := make(map[string]struct{})
+	for _, replace := range gomodFile.Replace {
+		replaces[replace.Old.Path] = struct{}{}
+	}
+
+	missingReplaces := false
+	for _, require := range gomodFile.Require {
+		modPath := require.Mod.Path
+		if !strings.HasPrefix(modPath, parentModuleWithTrailingSlash) {
+			continue
+		}
+		if _, isReplaced := replaces[modPath]; isReplaced {
+			continue
+		}
+		missingReplaces = true
+		rel := modPath[len(parentModuleWithTrailingSlash):]
+		if err := gomodFile.AddReplace(modPath, "", strings.Repeat("../", slashCount)+rel, ""); err != nil {
+			return "", false, fmt.Errorf("failed to add replace: %w", err)
+		}
+	}
+	if missingReplaces {
+		formatted, err := gomodFile.Format()
+		if err != nil {
+			return "", false, fmt.Errorf("failed to serialize go.mod file: %w", err)
+		}
+		return string(formatted), false, nil
+	}
+	return "", true, nil
+}

tooling/go/internal/local-overrides-enforcer/checker/checker_test.go

@@ -0,0 +1,70 @@
+package checker_test
+
+import (
+	"testing"
+
+	"github.com/CodeYourFuture/curriculum/tooling/go/internal/local-overrides-enforcer/checker"
+	"github.com/stretchr/testify/require"
+)
+
+func TestCorrect(t *testing.T) {
+	goModContent := `module github.com/CodeYourFuture/curriculum/org-cyf
+
+go 1.21.3
+
+replace github.com/CodeYourFuture/curriculum/common-content => ../common-content
+replace github.com/CodeYourFuture/curriculum/common-theme => ../common-theme
+
+require (
+	github.com/CodeYourFuture/curriculum/common-content v0.0.0-20240103071042-5b2177342232 // indirect
+	github.com/CodeYourFuture/curriculum/common-theme v0.0.0-20240103071042-5b2177342232 // indirect
+)
+`
+
+	newContent, ok, err := checker.CheckFile("/some/go.mod", []byte(goModContent), "github.com/CodeYourFuture/curriculum")
+	require.NoError(t, err)
+	require.True(t, ok)
+	require.Equal(t, "", newContent)
+}
+
+func TestMissingReplace(t *testing.T) {
+	goModContent := `module github.com/CodeYourFuture/curriculum/org-cyf
+
+	go 1.21.3
+
+	replace github.com/CodeYourFuture/curriculum/common-theme => ../common-theme
+
+	require (
+		github.com/CodeYourFuture/curriculum/common-content v0.0.0-20240103071042-5b2177342232 // indirect
+		github.com/CodeYourFuture/curriculum/common-theme v0.0.0-20240103071042-5b2177342232 // indirect
+	)
+`
+
+	newContent, ok, err := checker.CheckFile("/some/go.mod", []byte(goModContent), "github.com/CodeYourFuture/curriculum")
+	require.NoError(t, err)
+	require.False(t, ok)
+	require.Contains(t, newContent, "replace github.com/CodeYourFuture/curriculum/common-content => ../common-content")
+}
+
+func TestModuleNotChildOfParent(t *testing.T) {
+	goModContent := `module github.com/CodeYourFuture/wrong
+
+go 1.21.3
+
+replace github.com/CodeYourFuture/curriculum/common-content => ../common-content
+replace github.com/CodeYourFuture/curriculum/common-theme => ../common-theme
+
+require (
+	github.com/CodeYourFuture/curriculum/common-content v0.0.0-20240103071042-5b2177342232 // indirect
+	github.com/CodeYourFuture/curriculum/common-theme v0.0.0-20240103071042-5b2177342232 // indirect
+)
+`
+
+	_, _, err := checker.CheckFile("/some/go.mod", []byte(goModContent), "github.com/CodeYourFuture/curriculum")
+	require.ErrorContains(t, err, "module at path /some/go.mod was named github.com/CodeYourFuture/wrong which isn't a child of github.com/CodeYourFuture/curriculum")
+}
+
+func TestInvalidGoModFile(t *testing.T) {
+	_, _, err := checker.CheckFile("/some/go.mod", []byte("hello"), "github.com/CodeYourFuture/curriculum")
+	require.ErrorContains(t, err, "failed to parse /some/go.mod as go.mod file: ")
+}