Go: Make diagnostics unit-testable and add test for EmitCannotFindPackages

go/extractor/diagnostics/diagnostics.go

@@ -3,7 +3,7 @@ package diagnostics
 import (
 	"encoding/json"
 	"fmt"
-	"log"
+	"log/slog"
 	"os"
 	"strings"
 	"time"
@@ -56,18 +56,65 @@ type diagnostic struct {
 var diagnosticsEmitted, diagnosticsLimit uint = 0, 100
 var noDiagnosticDirPrinted bool = false
 
-func emitDiagnostic(sourceid, sourcename, markdownMessage string, severity diagnosticSeverity, visibility *visibilityStruct, location *locationStruct) {
-	if diagnosticsEmitted < diagnosticsLimit {
-		diagnosticsEmitted += 1
+type DiagnosticsWriter interface {
+	WriteDiagnostic(d diagnostic)
+}
 
-		diagnosticDir := os.Getenv("CODEQL_EXTRACTOR_GO_DIAGNOSTIC_DIR")
-		if diagnosticDir == "" {
-			if !noDiagnosticDirPrinted {
-				log.Println("No diagnostic directory set, so not emitting diagnostic")
-				noDiagnosticDirPrinted = true
-			}
-			return
+type FileDiagnosticsWriter struct {
+	diagnosticDir string
+}
+
+func (writer *FileDiagnosticsWriter) WriteDiagnostic(d diagnostic) {
+	if writer == nil {
+		return
+	}
+
+	content, err := json.Marshal(d)
+	if err != nil {
+		slog.Error("Failed to encode diagnostic as JSON", slog.Any("err", err))
+		return
+	}
+
+	targetFile, err := os.CreateTemp(writer.diagnosticDir, "go-extractor.*.json")
+	if err != nil {
+		slog.Error("Failed to create diagnostic file", slog.Any("err", err))
+		return
+	}
+	defer func() {
+		if err := targetFile.Close(); err != nil {
+			slog.Error("Failed to close diagnostic file", slog.Any("err", err))
+		}
+	}()
+
+	_, err = targetFile.Write(content)
+	if err != nil {
+		slog.Error("Failed to write to diagnostic file", slog.Any("err", err))
+	}
+}
+
+var DefaultWriter *FileDiagnosticsWriter = nil
+
+func NewFileDiagnosticsWriter() *FileDiagnosticsWriter {
+	diagnosticDir := os.Getenv("CODEQL_EXTRACTOR_GO_DIAGNOSTIC_DIR")
+	if diagnosticDir == "" {
+		if !noDiagnosticDirPrinted {
+			slog.Warn("No diagnostic directory set, so not emitting diagnostics")
+			noDiagnosticDirPrinted = true
 		}
+		return nil
+	}
+
+	return &FileDiagnosticsWriter{diagnosticDir}
+}
+
+func init() {
+	DefaultWriter = NewFileDiagnosticsWriter()
+}
+
+// Emits a diagnostic using the specified `DiagnosticsWriter`.
+func emitDiagnosticTo(writer DiagnosticsWriter, sourceid, sourcename, markdownMessage string, severity diagnosticSeverity, visibility *visibilityStruct, location *locationStruct) {
+	if diagnosticsEmitted < diagnosticsLimit {
+		diagnosticsEmitted += 1
 
 		timestamp := time.Now().UTC().Format("2006-01-02T15:04:05.000") + "Z"
 
@@ -93,33 +140,15 @@ func emitDiagnostic(sourceid, sourcename, markdownMessage string, severity diagn
 			}
 		}
 
-		content, err := json.Marshal(d)
-		if err != nil {
-			log.Println(err)
-			return
-		}
-
-		targetFile, err := os.CreateTemp(diagnosticDir, "go-extractor.*.json")
-		if err != nil {
-			log.Println("Failed to create diagnostic file: ")
-			log.Println(err)
-			return
-		}
-		defer func() {
-			if err := targetFile.Close(); err != nil {
-				log.Println("Failed to close diagnostic file:")
-				log.Println(err)
-			}
-		}()
-
-		_, err = targetFile.Write(content)
-		if err != nil {
-			log.Println("Failed to write to diagnostic file: ")
-			log.Println(err)
-		}
+		writer.WriteDiagnostic(d)
 	}
 }
 
+// Emits a diagnostic using the default `DiagnosticsWriter`.
+func emitDiagnostic(sourceid, sourcename, markdownMessage string, severity diagnosticSeverity, visibility *visibilityStruct, location *locationStruct) {
+	emitDiagnosticTo(DefaultWriter, sourceid, sourcename, markdownMessage, severity, visibility, location)
+}
+
 func EmitPackageDifferentOSArchitecture(pkgPath string) {
 	emitDiagnostic(
 		"go/autobuilder/package-different-os-architecture",
@@ -141,7 +170,7 @@ func plural(n int, singular, plural string) string {
 
 const maxNumPkgPaths = 5
 
-func EmitCannotFindPackages(pkgPaths []string) {
+func EmitCannotFindPackages(writer DiagnosticsWriter, pkgPaths []string) {
 	numPkgPaths := len(pkgPaths)
 
 	numPrinted := numPkgPaths
@@ -188,7 +217,8 @@ func EmitCannotFindPackages(pkgPaths []string) {
 			"If any of the packages are already present in the repository, but were not found, then you may need a [custom build command](https://docs.github.com/en/code-security/how-tos/scan-code-for-vulnerabilities/manage-your-configuration/codeql-code-scanning-for-compiled-languages)."
 	}
 
-	emitDiagnostic(
+	emitDiagnosticTo(
+		writer,
 		"go/autobuilder/package-not-found",
 		"Some packages could not be found",
 		message,

go/extractor/diagnostics/diagnostics_test.go

@@ -0,0 +1,85 @@
+package diagnostics
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+type memoryDiagnosticsWriter struct {
+	diagnostics []diagnostic
+}
+
+func newMemoryDiagnosticsWriter() *memoryDiagnosticsWriter {
+	return &memoryDiagnosticsWriter{[]diagnostic{}}
+}
+
+func (writer *memoryDiagnosticsWriter) WriteDiagnostic(d diagnostic) {
+	writer.diagnostics = append(writer.diagnostics, d)
+}
+
+func Test_EmitCannotFindPackages_Default(t *testing.T) {
+	writer := newMemoryDiagnosticsWriter()
+
+	// Clear environment variables that affect the diagnostic message.
+	t.Setenv("GITHUB_EVENT_NAME", "")
+	t.Setenv("GITHUB_ACTIONS", "")
+
+	EmitCannotFindPackages(writer, []string{"github.com/github/foo"})
+
+	assert.Len(t, writer.diagnostics, 1, "Expected one diagnostic to be emitted")
+
+	d := writer.diagnostics[0]
+	assert.Equal(t, d.Source.Id, "go/autobuilder/package-not-found")
+	assert.Equal(t, d.Severity, string(severityWarning))
+	assert.True(t, d.Visibility.CliSummaryTable)
+	assert.True(t, d.Visibility.StatusPage)
+	assert.True(t, d.Visibility.Telemetry)
+	// Non-Actions suggestion for private registries
+	assert.Contains(t, d.MarkdownMessage, "ensure that the necessary credentials and environment variables are set up")
+	// Custom build command suggestion
+	assert.Contains(t, d.MarkdownMessage, "If any of the packages are already present in the repository")
+}
+
+func Test_EmitCannotFindPackages_Dynamic(t *testing.T) {
+	writer := newMemoryDiagnosticsWriter()
+
+	// Set environment variables that affect the diagnostic message.
+	t.Setenv("GITHUB_EVENT_NAME", "dynamic")
+	t.Setenv("GITHUB_ACTIONS", "true")
+
+	EmitCannotFindPackages(writer, []string{"github.com/github/foo"})
+
+	assert.Len(t, writer.diagnostics, 1, "Expected one diagnostic to be emitted")
+
+	d := writer.diagnostics[0]
+	assert.Equal(t, d.Source.Id, "go/autobuilder/package-not-found")
+	assert.Equal(t, d.Severity, string(severityWarning))
+	// Dynamic workflow suggestion for private registries
+	assert.Contains(t, d.MarkdownMessage, "can grant access to private registries for GitHub security products")
+	// No default suggestions for private registries and custom build command
+	assert.NotContains(t, d.MarkdownMessage, "ensure that the necessary credentials and environment variables are set up")
+	assert.NotContains(t, d.MarkdownMessage, "If any of the packages are already present in the repository")
+}
+
+func Test_EmitCannotFindPackages_Actions(t *testing.T) {
+	writer := newMemoryDiagnosticsWriter()
+
+	// Set environment variables that affect the diagnostic message.
+	t.Setenv("GITHUB_EVENT_NAME", "push")
+	t.Setenv("GITHUB_ACTIONS", "true")
+
+	EmitCannotFindPackages(writer, []string{"github.com/github/foo"})
+
+	assert.Len(t, writer.diagnostics, 1, "Expected one diagnostic to be emitted")
+
+	d := writer.diagnostics[0]
+	assert.Equal(t, d.Source.Id, "go/autobuilder/package-not-found")
+	assert.Equal(t, d.Severity, string(severityWarning))
+	// Advanced workflow suggestion for private registries
+	assert.Contains(t, d.MarkdownMessage, "add a step to your workflow which sets up")
+	// No default suggestion for private registries
+	assert.NotContains(t, d.MarkdownMessage, "ensure that the necessary credentials and environment variables are set up")
+	// Custom build command suggestion
+	assert.Contains(t, d.MarkdownMessage, "If any of the packages are already present in the repository")
+}

go/extractor/extractor.go

@@ -223,7 +223,7 @@ func ExtractWithFlags(buildFlags []string, patterns []string, extractTests bool,
 	})
 
 	if len(pkgsNotFound) > 0 {
-		diagnostics.EmitCannotFindPackages(pkgsNotFound)
+		diagnostics.EmitCannotFindPackages(diagnostics.DefaultWriter, pkgsNotFound)
 	}
 
 	for _, pkg := range pkgs {

go/extractor/go.mod

@@ -13,4 +13,10 @@ require (
 	golang.org/x/tools v0.41.0
 )
 
-require golang.org/x/sync v0.19.0 // indirect
+require (
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	github.com/stretchr/testify v1.11.1 // indirect
+	golang.org/x/sync v0.19.0 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)

go/extractor/go.sum

@@ -1,8 +1,17 @@
+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/google/go-cmp v0.6.0 h1:ofyhxvXcZhMsU5ulbFiLKl/XBFqE1GSq7atu8tAmTRI=
 github.com/google/go-cmp v0.6.0/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
+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 v1.11.1 h1:7s2iGBzp5EwR7/aIZr8ao5+dra3wiQyKjjFuvgVKu7U=
+github.com/stretchr/testify v1.11.1/go.mod h1:wZwfW3scLgRK+23gO65QZefKpKQRnfz6sD981Nm4B6U=
 golang.org/x/mod v0.32.0 h1:9F4d3PHLljb6x//jOyokMv3eX+YDeepZSEo3mFJy93c=
 golang.org/x/mod v0.32.0/go.mod h1:SgipZ/3h2Ci89DlEtEXWUk/HteuRin+HHhN+WbNhguU=
 golang.org/x/sync v0.19.0 h1:vV+1eWNmZ5geRlYjzm2adRgW2/mcpevXNg50YZtPCE4=
 golang.org/x/sync v0.19.0/go.mod h1:9KTHXmSnoGruLpwFjVSX0lNNA75CykiMECbovNTZqGI=
 golang.org/x/tools v0.41.0 h1:a9b8iMweWG+S0OBnlU36rzLp20z1Rp10w+IY2czHTQc=
 golang.org/x/tools v0.41.0/go.mod h1:XSY6eDqxVNiYgezAVqqCeihT4j1U2CCsqvH3WhQpnlg=
+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=