fix #3041: allow injecting copied files

CHANGELOG.md

@@ -41,6 +41,12 @@
     }
     ```
 
+* Support `--inject` with a file loaded using the `copy` loader ([#3041](https://github.com/evanw/esbuild/issues/3041))
+
+    This release now allows you to use `--inject` with a file that is loaded using the `copy` loader. The `copy` loader copies the imported file to the output directory verbatim and rewrites the path in the `import` statement to point to the copied output file. When used with `--inject`, this means the injected file will be copied to the output directory as-is and a bare `import` statement for that file will be inserted in any non-copy output files that esbuild generates.
+
+    Note that since esbuild doesn't parse the contents of copied files, esbuild will not expose any of the export names as usable imports when you do this (in the way that esbuild's `--inject` feature is typically used). However, any side-effects that the injected file has will still occur.
+
 ## 0.17.15
 
 * Allow keywords as type parameter names in mapped types ([#3033](https://github.com/evanw/esbuild/issues/3033))

internal/bundler/bundler.go

@@ -530,9 +530,17 @@ func parseFile(args parseArgs) {
 		// "options" object to populate the "InjectedFiles" field. So we must
 		// only send on the "inject" channel after we're done using the "options"
 		// object so we don't introduce a data race.
+		isCopyLoader := loader == config.LoaderCopy
+		if isCopyLoader && args.skipResolve {
+			// This is not allowed because the import path would have to be rewritten,
+			// but import paths are not rewritten when bundling isn't enabled.
+			args.log.AddError(nil, logger.Range{},
+				fmt.Sprintf("Cannot inject %q with the \"copy\" loader without bundling enabled", source.PrettyPath))
+		}
 		args.inject <- config.InjectedFile{
-			Source:  source,
-			Exports: exports,
+			Source:       source,
+			Exports:      exports,
+			IsCopyLoader: isCopyLoader,
 		}
 	}
 

internal/bundler_tests/bundler_loader_test.go

@@ -1498,3 +1498,42 @@ func TestLoaderCopyStartsWithDotRelPath(t *testing.T) {
 		},
 	})
 }
+
+func TestLoaderCopyWithInjectedFileNoBundle(t *testing.T) {
+	loader_suite.expectBundled(t, bundled{
+		files: map[string]string{
+			"/src/entry.ts":  `console.log('in entry.ts')`,
+			"/src/inject.js": `console.log('in inject.js')`,
+		},
+		entryPaths: []string{"/src/entry.ts"},
+		options: config.Options{
+			AbsOutputDir: "/out",
+			InjectPaths:  []string{"/src/inject.js"},
+			ExtensionToLoader: map[string]config.Loader{
+				".ts": config.LoaderTS,
+				".js": config.LoaderCopy,
+			},
+		},
+		expectedScanLog: `ERROR: Cannot inject "src/inject.js" with the "copy" loader without bundling enabled
+`,
+	})
+}
+
+func TestLoaderCopyWithInjectedFileBundle(t *testing.T) {
+	loader_suite.expectBundled(t, bundled{
+		files: map[string]string{
+			"/src/entry.ts":  `console.log('in entry.ts')`,
+			"/src/inject.js": `console.log('in inject.js')`,
+		},
+		entryPaths: []string{"/src/entry.ts"},
+		options: config.Options{
+			Mode:         config.ModeBundle,
+			AbsOutputDir: "/out",
+			InjectPaths:  []string{"/src/inject.js"},
+			ExtensionToLoader: map[string]config.Loader{
+				".ts": config.LoaderTS,
+				".js": config.LoaderCopy,
+			},
+		},
+	})
+}

internal/bundler_tests/snapshots/snapshots_loader.txt

@@ -342,6 +342,15 @@ TestLoaderCopyWithFormat
 
 ---------- /out/assets/some.file ----------
 stuff
+================================================================================
+TestLoaderCopyWithInjectedFileBundle
+---------- /out/inject-IFR6YGWW.js ----------
+console.log('in inject.js')
+---------- /out/entry.js ----------
+// src/entry.ts
+import "./inject-IFR6YGWW.js";
+console.log("in entry.ts");
+
 ================================================================================
 TestLoaderCopyWithTransform
 ---------- /out/src/entry.js ----------

internal/config/config.go

@@ -559,9 +559,10 @@ type InjectedDefine struct {
 }
 
 type InjectedFile struct {
-	Exports    []InjectableExport
-	DefineName string
-	Source     logger.Source
+	Exports      []InjectableExport
+	DefineName   string // For injected files generated when you "--define" a non-literal
+	Source       logger.Source
+	IsCopyLoader bool // If you set the loader to "copy" (see https://github.com/evanw/esbuild/issues/3041)
 }
 
 type InjectableExport struct {

internal/js_parser/js_parser.go

@@ -15394,7 +15394,7 @@ func (p *parser) scanForImportsAndExports(stmts []js_ast.Stmt) (result importsEx
 				if p.options.ts.Parse && foundImports && isUnusedInTypeScript && (p.options.unusedImportFlagsTS&config.UnusedImportKeepStmt) == 0 {
 					// Ignore import records with a pre-filled source index. These are
 					// for injected files and we definitely do not want to trim these.
-					if !record.SourceIndex.IsValid() {
+					if !record.SourceIndex.IsValid() && !record.CopySourceIndex.IsValid() {
 						record.Flags |= ast.IsUnused
 						continue
 					}
@@ -15879,7 +15879,11 @@ func Parse(log logger.Log, source logger.Source, options Options) (result js_ast
 			}
 		}
 
-		before = p.generateImportStmt(file.Source.KeyPath.Text, exportsNoConflict, &file.Source.Index, before, symbols)
+		if file.IsCopyLoader {
+			before = p.generateImportStmt(file.Source.KeyPath.Text, exportsNoConflict, before, symbols, nil, &file.Source.Index)
+		} else {
+			before = p.generateImportStmt(file.Source.KeyPath.Text, exportsNoConflict, before, symbols, &file.Source.Index, nil)
+		}
 	}
 
 	// Bind symbols in a second pass over the AST. I started off doing this in a
@@ -16326,9 +16330,10 @@ func (p *parser) computeCharacterFrequency() *js_ast.CharFreq {
 func (p *parser) generateImportStmt(
 	path string,
 	imports []string,
-	sourceIndex *uint32,
 	parts []js_ast.Part,
 	symbols map[string]js_ast.LocRef,
+	sourceIndex *uint32,
+	copySourceIndex *uint32,
 ) []js_ast.Part {
 	var loc logger.Loc
 	isFirst := true
@@ -16347,6 +16352,9 @@ func (p *parser) generateImportStmt(
 	if sourceIndex != nil {
 		p.importRecords[importRecordIndex].SourceIndex = ast.MakeIndex32(*sourceIndex)
 	}
+	if copySourceIndex != nil {
+		p.importRecords[importRecordIndex].CopySourceIndex = ast.MakeIndex32(*copySourceIndex)
+	}
 	declaredSymbols[0] = js_ast.DeclaredSymbol{Ref: namespaceRef, IsTopLevel: true}
 
 	// Create per-import information
@@ -16396,7 +16404,7 @@ func (p *parser) toAST(before, parts, after []js_ast.Part, hashbang string, dire
 	if len(p.runtimeImports) > 0 && !p.options.omitRuntimeForTests {
 		keys := sortedKeysOfMapStringLocRef(p.runtimeImports)
 		sourceIndex := runtime.SourceIndex
-		before = p.generateImportStmt("<runtime>", keys, &sourceIndex, before, p.runtimeImports)
+		before = p.generateImportStmt("<runtime>", keys, before, p.runtimeImports, &sourceIndex, nil)
 	}
 
 	// Insert an import statement for any jsx runtime imports we generated
@@ -16411,14 +16419,14 @@ func (p *parser) toAST(before, parts, after []js_ast.Part, hashbang string, dire
 			path = path + "/jsx-runtime"
 		}
 
-		before = p.generateImportStmt(path, keys, nil, before, p.jsxRuntimeImports)
+		before = p.generateImportStmt(path, keys, before, p.jsxRuntimeImports, nil, nil)
 	}
 
 	// Insert an import statement for any legacy jsx imports we generated (i.e., createElement)
 	if len(p.jsxLegacyImports) > 0 && !p.options.omitJSXRuntimeForTests {
 		keys := sortedKeysOfMapStringLocRef(p.jsxLegacyImports)
 		path := p.options.jsx.ImportSource
-		before = p.generateImportStmt(path, keys, nil, before, p.jsxLegacyImports)
+		before = p.generateImportStmt(path, keys, before, p.jsxLegacyImports, nil, nil)
 	}
 
 	// Generated imports are inserted before other code instead of appending them