fix #879: provide "kind" to "onResolve" plugins

CHANGELOG.md

@@ -6,6 +6,40 @@
 
     This release fixes an issue where esbuild could potentially crash sometimes with a concurrent map write when using injected files and entry points that were neither relative nor absolute paths. This was an edge case where esbuild's low-level file subsystem was being used without being behind a mutex lock. This regression was likely introduced in version 0.8.21. The cause of the crash has been fixed.
 
+* Provide `kind` to `onResolve` plugins ([#879](https://github.com/evanw/esbuild/issues/879))
+
+    Plugins that add `onResolve` callbacks now have access to the `kind` parameter which tells you what kind of import is being resolved. It will be one of the following values:
+
+	* `"entry-point"` in JS (`api.ResolveEntryPoint` in Go)
+
+        An entry point provided by the user
+
+	* `"import-statement"` in JS (`api.ResolveJSImportStatement` in Go)
+
+        A JavaScript `import` or `export` statement
+
+	* `"require-call"` in JS (`api.ResolveJSRequireCall` in Go)
+
+        A JavaScript call to `require(...)` with a string argument
+
+	* `"dynamic-import"` in JS (`api.ResolveJSDynamicImport` in Go)
+
+        A JavaScript `import(...)` expression with a string argument
+
+	* `"require-resolve"` in JS (`api.ResolveJSRequireResolve` in Go)
+
+        A JavaScript call to `require.resolve(...)` with a string argument
+
+	* `"import-rule"` in JS (`api.ResolveCSSImportRule` in Go)
+
+        A CSS `@import` rule
+
+	* `"url-token"` in JS (`api.ResolveCSSURLToken` in Go)
+
+        A CSS `url(...)` token
+
+    These values are pretty much identical to the `kind` field in the JSON metadata file.
+
 ## 0.8.51
 
 * The stderr log format now contains line numbers after file names ([#865](https://github.com/evanw/esbuild/issues/865))

cmd/esbuild/service.go

@@ -617,6 +617,31 @@ func (service *serviceType) convertPlugins(key int, jsPlugins interface{}) ([]ap
 					return result, nil
 				}
 
+				var kind string
+				switch args.Kind {
+				case api.ResolveEntryPoint:
+					kind = "entry-point"
+
+				// JS
+				case api.ResolveJSImportStatement:
+					kind = "import-statement"
+				case api.ResolveJSRequireCall:
+					kind = "require-call"
+				case api.ResolveJSDynamicImport:
+					kind = "dynamic-import"
+				case api.ResolveJSRequireResolve:
+					kind = "require-resolve"
+
+				// CSS
+				case api.ResolveCSSImportRule:
+					kind = "import-rule"
+				case api.ResolveCSSURLToken:
+					kind = "url-token"
+
+				default:
+					panic("Internal error")
+				}
+
 				response := service.sendRequest(map[string]interface{}{
 					"command":    "resolve",
 					"key":        key,
@@ -625,6 +650,7 @@ func (service *serviceType) convertPlugins(key int, jsPlugins interface{}) ([]ap
 					"importer":   args.Importer,
 					"namespace":  args.Namespace,
 					"resolveDir": args.ResolveDir,
+					"kind":       kind,
 					"pluginData": args.PluginData,
 				}).(map[string]interface{})
 

internal/ast/ast.go

@@ -9,8 +9,11 @@ import "github.com/evanw/esbuild/internal/logger"
 type ImportKind uint8
 
 const (
+	// An entry point provided by the user
+	ImportEntryPoint ImportKind = iota
+
 	// An ES6 import or re-export statement
-	ImportStmt ImportKind = iota
+	ImportStmt
 
 	// A call to "require()"
 	ImportRequire
@@ -26,9 +29,6 @@ const (
 
 	// A CSS "url(...)" token
 	ImportURL
-
-	// An entry point provided by the user
-	ImportEntryPoint
 )
 
 func (kind ImportKind) StringForMetafile() string {

internal/bundler/bundler.go

@@ -638,6 +638,7 @@ func runOnResolvePlugins(
 	resolverArgs := config.OnResolveArgs{
 		Path:       path,
 		ResolveDir: absResolveDir,
+		Kind:       kind,
 		PluginData: pluginData,
 	}
 	applyPath := logger.Path{Text: path}

internal/config/config.go

@@ -5,6 +5,7 @@ import (
 	"regexp"
 	"sync"
 
+	"github.com/evanw/esbuild/internal/ast"
 	"github.com/evanw/esbuild/internal/compat"
 	"github.com/evanw/esbuild/internal/js_ast"
 	"github.com/evanw/esbuild/internal/logger"
@@ -321,6 +322,7 @@ type OnResolveArgs struct {
 	Path       string
 	Importer   logger.Path
 	ResolveDir string
+	Kind       ast.ImportKind
 	PluginData interface{}
 }
 

lib/common.ts

@@ -637,6 +637,7 @@ export function createChannel(streamIn: StreamIn): StreamOut {
                 importer: request.importer,
                 namespace: request.namespace,
                 resolveDir: request.resolveDir,
+                kind: request.kind,
                 pluginData: stash.load(request.pluginData),
               });
 

lib/stdio_protocol.ts

@@ -120,6 +120,7 @@ export interface OnResolveRequest {
   importer: string;
   namespace: string;
   resolveDir: string;
+  kind: string;
   pluginData: number;
 }
 

lib/types.ts

@@ -192,9 +192,23 @@ export interface OnResolveArgs {
   importer: string;
   namespace: string;
   resolveDir: string;
+  kind: ResolveKind;
   pluginData: any;
 }
 
+export type ResolveKind =
+  | 'entry-point'
+
+  // JS
+  | 'import-statement'
+  | 'require-call'
+  | 'dynamic-import'
+  | 'require-resolve'
+
+  // CSS
+  | 'import-rule'
+  | 'url-token'
+
 export interface OnResolveResult {
   pluginName?: string;
 

pkg/api/api.go

@@ -407,6 +407,7 @@ type OnResolveArgs struct {
 	Importer   string
 	Namespace  string
 	ResolveDir string
+	Kind       ResolveKind
 	PluginData interface{}
 }
 
@@ -444,3 +445,15 @@ type OnLoadResult struct {
 	Loader     Loader
 	PluginData interface{}
 }
+
+type ResolveKind uint8
+
+const (
+	ResolveEntryPoint ResolveKind = iota
+	ResolveJSImportStatement
+	ResolveJSRequireCall
+	ResolveJSDynamicImport
+	ResolveJSRequireResolve
+	ResolveCSSImportRule
+	ResolveCSSURLToken
+)

pkg/api/api_impl.go

@@ -13,6 +13,7 @@ import (
 	"sync/atomic"
 	"time"
 
+	"github.com/evanw/esbuild/internal/ast"
 	"github.com/evanw/esbuild/internal/bundler"
 	"github.com/evanw/esbuild/internal/cache"
 	"github.com/evanw/esbuild/internal/compat"
@@ -1117,11 +1118,32 @@ func (impl *pluginImpl) OnResolve(options OnResolveOptions, callback func(OnReso
 		Filter:    filter,
 		Namespace: options.Namespace,
 		Callback: func(args config.OnResolveArgs) (result config.OnResolveResult) {
+			var kind ResolveKind
+			switch args.Kind {
+			case ast.ImportEntryPoint:
+				kind = ResolveEntryPoint
+			case ast.ImportStmt:
+				kind = ResolveJSImportStatement
+			case ast.ImportRequire:
+				kind = ResolveJSRequireCall
+			case ast.ImportDynamic:
+				kind = ResolveJSDynamicImport
+			case ast.ImportRequireResolve:
+				kind = ResolveJSRequireResolve
+			case ast.ImportAt:
+				kind = ResolveCSSImportRule
+			case ast.ImportURL:
+				kind = ResolveCSSURLToken
+			default:
+				panic("Internal error")
+			}
+
 			response, err := callback(OnResolveArgs{
 				Path:       args.Path,
 				Importer:   args.Importer.Text,
 				Namespace:  args.Importer.Namespace,
 				ResolveDir: args.ResolveDir,
+				Kind:       kind,
 				PluginData: args.PluginData,
 			})
 			result.PluginName = response.PluginName