pass file system errors to callers (#348)

cmd/esbuild/service.go

@@ -13,7 +13,6 @@ import (
 	"os"
 	"runtime/debug"
 	"sync"
-	"syscall"
 
 	"github.com/evanw/esbuild/internal/fs"
 	"github.com/evanw/esbuild/pkg/api"
@@ -239,11 +238,11 @@ func (service *serviceType) handleTransformRequest(id uint32, request map[string
 	transformInput := input
 	if inputFS {
 		realFS := fs.RealFS()
-		bytes, ok := realFS.ReadFile(input)
-		if !ok {
-			return encodeErrorPacket(id, syscall.ENOENT)
+		bytes, err := realFS.ReadFile(input)
+		if err == nil {
+			err = os.Remove(input)
 		}
-		if err := os.Remove(input); err != nil {
+		if err != nil {
 			return encodeErrorPacket(id, err)
 		}
 		transformInput = string(bytes)

internal/bundler/bundler.go

@@ -12,6 +12,7 @@ import (
 	"sort"
 	"strings"
 	"sync"
+	"syscall"
 	"unicode"
 	"unicode/utf8"
 
@@ -118,11 +119,16 @@ func parseFile(args parseArgs) {
 		loader = stdin.Loader
 	} else if args.keyPath.IsAbsolute {
 		// Read normal modules from disk
-		var ok bool
-		source.Contents, ok = args.res.Read(args.keyPath.Text)
-		if !ok {
-			args.log.AddRangeError(args.importSource, args.pathRange,
-				fmt.Sprintf("Could not read from file: %s", args.keyPath.Text))
+		var err error
+		source.Contents, err = args.fs.ReadFile(args.keyPath.Text)
+		if err != nil {
+			if err == syscall.ENOENT {
+				args.log.AddRangeError(args.importSource, args.pathRange,
+					fmt.Sprintf("Could not read from file: %s", args.keyPath.Text))
+			} else {
+				args.log.AddRangeError(args.importSource, args.pathRange,
+					fmt.Sprintf("Cannot read file %q: %s", args.res.PrettyPath(args.keyPath.Text), err.Error()))
+			}
 			args.results <- parseResult{}
 			return
 		}
@@ -305,7 +311,7 @@ func parseFile(args parseArgs) {
 
 	// Attempt to parse the source map if present
 	if loader.CanHaveSourceMap() && args.options.SourceMap != config.SourceMapNone && result.file.ast.SourceMapComment.Text != "" {
-		if path, contents := extractSourceMapFromComment(args.log, args.fs, &source, result.file.ast.SourceMapComment); contents != nil {
+		if path, contents := extractSourceMapFromComment(args.log, args.fs, args.res, &source, result.file.ast.SourceMapComment); contents != nil {
 			prettyPath := path.Text
 			if path.IsAbsolute {
 				prettyPath = args.res.PrettyPath(prettyPath)
@@ -321,7 +327,7 @@ func parseFile(args parseArgs) {
 	args.results <- result
 }
 
-func extractSourceMapFromComment(log logging.Log, fs fs.FS, source *logging.Source, comment ast.Span) (ast.Path, *string) {
+func extractSourceMapFromComment(log logging.Log, fs fs.FS, res resolver.Resolver, source *logging.Source, comment ast.Span) (ast.Path, *string) {
 	// Data URL
 	if strings.HasPrefix(comment.Text, "data:") {
 		if strings.HasPrefix(comment.Text, "data:application/json;") {
@@ -348,9 +354,13 @@ func extractSourceMapFromComment(log logging.Log, fs fs.FS, source *logging.Sour
 	// Absolute path
 	if source.KeyPath.IsAbsolute {
 		absPath := fs.Join(fs.Dir(source.KeyPath.Text), comment.Text)
-		contents, ok := fs.ReadFile(absPath)
-		if !ok {
-			log.AddRangeWarning(source, comment.Range, fmt.Sprintf("Could not find source map file: %s", absPath))
+		contents, err := fs.ReadFile(absPath)
+		if err != nil {
+			if err == syscall.ENOENT {
+				log.AddRangeWarning(source, comment.Range, fmt.Sprintf("Could not find source map file: %s", absPath))
+				return ast.Path{}, nil
+			}
+			log.AddRangeError(source, comment.Range, fmt.Sprintf("Cannot read file %q: %s", res.PrettyPath(absPath), err.Error()))
 			return ast.Path{}, nil
 		}
 		return ast.Path{IsAbsolute: true, Text: absPath}, &contents

internal/fs/fs.go

@@ -7,6 +7,7 @@ import (
 	"path/filepath"
 	"strings"
 	"sync"
+	"syscall"
 )
 
 type EntryKind uint8
@@ -90,7 +91,7 @@ type FS interface {
 	// The returned map is immutable and is cached across invocations. Do not
 	// mutate it.
 	ReadDirectory(path string) map[string]*Entry
-	ReadFile(path string) (string, bool)
+	ReadFile(path string) (string, error)
 
 	// This is part of the interface because the mock interface used for tests
 	// should not depend on file system behavior (i.e. different slashes for
@@ -146,9 +147,12 @@ func (fs *mockFS) ReadDirectory(path string) map[string]*Entry {
 	return fs.dirs[path]
 }
 
-func (fs *mockFS) ReadFile(path string) (string, bool) {
+func (fs *mockFS) ReadFile(path string) (string, error) {
 	contents, ok := fs.files[path]
-	return contents, ok
+	if !ok {
+		return "", syscall.ENOENT
+	}
+	return contents, nil
 }
 
 func (*mockFS) Abs(p string) (string, bool) {
@@ -315,11 +319,16 @@ func (fs *realFS) ReadDirectory(dir string) map[string]*Entry {
 	return entries
 }
 
-func (fs *realFS) ReadFile(path string) (string, bool) {
+func (fs *realFS) ReadFile(path string) (string, error) {
 	BeforeFileOpen()
 	defer AfterFileClose()
 	buffer, err := ioutil.ReadFile(path)
-	return string(buffer), err == nil
+	if err != nil {
+		if pathErr, ok := err.(*os.PathError); ok {
+			return "", pathErr.Unwrap()
+		}
+	}
+	return string(buffer), err
 }
 
 func (*realFS) Abs(p string) (string, bool) {

internal/fs/fs_test.go

@@ -14,23 +14,23 @@ func TestBasic(t *testing.T) {
 	})
 
 	// Test a missing file
-	_, ok := fs.ReadFile("/missing.txt")
-	if ok {
+	_, err := fs.ReadFile("/missing.txt")
+	if err == nil {
 		t.Fatal("Unexpectedly found /missing.txt")
 	}
 
 	// Test an existing file
-	readme, ok := fs.ReadFile("/README.md")
-	if !ok {
+	readme, err := fs.ReadFile("/README.md")
+	if err != nil {
 		t.Fatal("Expected to find /README.md")
 	}
 	if readme != "// README.md" {
 		t.Fatalf("Incorrect contents for /README.md: %q", readme)
 	}
 
 	// Test an existing nested file
-	index, ok := fs.ReadFile("/src/index.js")
-	if !ok {
+	index, err := fs.ReadFile("/src/index.js")
+	if err != nil {
 		t.Fatal("Expected to find /src/index.js")
 	}
 	if index != "// src/index.js" {