Support go-to-definition for non-existent files

Author: andrewbranch

src/harness/client.ts

@@ -527,6 +527,9 @@ namespace ts.server {
         private decodeSpan(span: protocol.TextSpan & { file: string }): TextSpan;
         private decodeSpan(span: protocol.TextSpan, fileName: string, lineMap?: number[]): TextSpan;
         private decodeSpan(span: protocol.TextSpan & { file: string }, fileName?: string, lineMap?: number[]): TextSpan {
+            if (span.start.line === 1 && span.start.offset === 1 && span.end.line === 1 && span.end.offset === 1) {
+                return { start: 0, length: 0 };
+            }
             fileName = fileName || span.file;
             lineMap = lineMap || this.getLineMap(fileName);
             return createTextSpanFromBounds(

src/harness/fourslashImpl.ts

@@ -688,7 +688,7 @@ namespace FourSlash {
             this.verifyGoToXWorker(toArray(endMarker), () => this.getGoToDefinition());
         }
 
-        public verifyGoToDefinition(arg0: any, endMarkerNames?: ArrayOrSingle<string>) {
+        public verifyGoToDefinition(arg0: any, endMarkerNames?: ArrayOrSingle<string> | { file: string }) {
             this.verifyGoToX(arg0, endMarkerNames, () => this.getGoToDefinitionAndBoundSpan());
         }
 
@@ -705,7 +705,7 @@ namespace FourSlash {
                 this.languageService.getTypeDefinitionAtPosition(this.activeFile.fileName, this.currentCaretPosition));
         }
 
-        private verifyGoToX(arg0: any, endMarkerNames: ArrayOrSingle<string> | undefined, getDefs: () => readonly ts.DefinitionInfo[] | ts.DefinitionInfoAndBoundSpan | undefined) {
+        private verifyGoToX(arg0: any, endMarkerNames: ArrayOrSingle<string> | { file: string } | undefined, getDefs: () => readonly ts.DefinitionInfo[] | ts.DefinitionInfoAndBoundSpan | undefined) {
             if (endMarkerNames) {
                 this.verifyGoToXPlain(arg0, endMarkerNames, getDefs);
             }
@@ -725,7 +725,7 @@ namespace FourSlash {
             }
         }
 
-        private verifyGoToXPlain(startMarkerNames: ArrayOrSingle<string>, endMarkerNames: ArrayOrSingle<string>, getDefs: () => readonly ts.DefinitionInfo[] | ts.DefinitionInfoAndBoundSpan | undefined) {
+        private verifyGoToXPlain(startMarkerNames: ArrayOrSingle<string>, endMarkerNames: ArrayOrSingle<string> | { file: string }, getDefs: () => readonly ts.DefinitionInfo[] | ts.DefinitionInfoAndBoundSpan | undefined) {
             for (const start of toArray(startMarkerNames)) {
                 this.verifyGoToXSingle(start, endMarkerNames, getDefs);
             }
@@ -737,12 +737,12 @@ namespace FourSlash {
             }
         }
 
-        private verifyGoToXSingle(startMarkerName: string, endMarkerNames: ArrayOrSingle<string>, getDefs: () => readonly ts.DefinitionInfo[] | ts.DefinitionInfoAndBoundSpan | undefined) {
+        private verifyGoToXSingle(startMarkerName: string, endMarkerNames: ArrayOrSingle<string> | { file: string }, getDefs: () => readonly ts.DefinitionInfo[] | ts.DefinitionInfoAndBoundSpan | undefined) {
             this.goToMarker(startMarkerName);
             this.verifyGoToXWorker(toArray(endMarkerNames), getDefs, startMarkerName);
         }
 
-        private verifyGoToXWorker(endMarkers: readonly string[], getDefs: () => readonly ts.DefinitionInfo[] | ts.DefinitionInfoAndBoundSpan | undefined, startMarkerName?: string) {
+        private verifyGoToXWorker(endMarkers: readonly (string | { file: string })[], getDefs: () => readonly ts.DefinitionInfo[] | ts.DefinitionInfoAndBoundSpan | undefined, startMarkerName?: string) {
             const defs = getDefs();
             let definitions: readonly ts.DefinitionInfo[];
             let testName: string;
@@ -762,21 +762,22 @@ namespace FourSlash {
                 this.raiseError(`${testName} failed - expected to find ${endMarkers.length} definitions but got ${definitions.length}`);
             }
 
-            ts.zipWith(endMarkers, definitions, (endMarker, definition, i) => {
-                const marker = this.getMarkerByName(endMarker);
-                if (ts.comparePaths(marker.fileName, definition.fileName, /*ignoreCase*/ true) !== ts.Comparison.EqualTo || marker.position !== definition.textSpan.start) {
-                    const filesToDisplay = ts.deduplicate([marker.fileName, definition.fileName], ts.equateValues);
-                    const markers = [{ text: "EXPECTED", fileName: marker.fileName, position: marker.position }, { text: "ACTUAL", fileName: definition.fileName, position: definition.textSpan.start }];
+            ts.zipWith(endMarkers, definitions, (endMarkerOrFileResult, definition, i) => {
+                const expectedFileName = typeof endMarkerOrFileResult === "string" ? this.getMarkerByName(endMarkerOrFileResult).fileName : endMarkerOrFileResult.file;
+                const expectedPosition = typeof endMarkerOrFileResult === "string" ? this.getMarkerByName(endMarkerOrFileResult).position : 0;
+                if (ts.comparePaths(expectedFileName, definition.fileName, /*ignoreCase*/ true) !== ts.Comparison.EqualTo || expectedPosition !== definition.textSpan.start) {
+                    const filesToDisplay = ts.deduplicate([expectedFileName, definition.fileName], ts.equateValues);
+                    const markers = [{ text: "EXPECTED", fileName: expectedFileName, position: expectedPosition }, { text: "ACTUAL", fileName: definition.fileName, position: definition.textSpan.start }];
                     const text = filesToDisplay.map(fileName => {
                         const markersToRender = markers.filter(m => m.fileName === fileName).sort((a, b) => b.position - a.position);
-                        let fileContent = this.getFileContent(fileName);
+                        let fileContent = this.tryGetFileContent(fileName) || "";
                         for (const marker of markersToRender) {
                             fileContent = fileContent.slice(0, marker.position) + `\x1b[1;4m/*${marker.text}*/\x1b[0;31m` + fileContent.slice(marker.position);
                         }
                         return `// @Filename: ${fileName}\n${fileContent}`;
                     }).join("\n\n");
 
-                    this.raiseError(`${testName} failed for definition ${endMarker} (${i}): expected ${marker.fileName} at ${marker.position}, got ${definition.fileName} at ${definition.textSpan.start}\n\n${text}\n`);
+                    this.raiseError(`${testName} failed for definition ${endMarkerOrFileResult} (${i}): expected ${expectedFileName} at ${expectedPosition}, got ${definition.fileName} at ${definition.textSpan.start}\n\n${text}\n`);
                 }
             });
         }

src/services/services.ts

@@ -2492,6 +2492,17 @@ namespace ts {
             return refactor.getEditsForRefactor(getRefactorContext(file, positionOrRange, preferences, formatOptions), refactorName, actionName);
         }
 
+        function toLineColumnOffset(fileName: string, position: number): LineAndCharacter {
+            // Go to Definition supports returning a zero-length span at position 0 for
+            // non-existent files. We need to special-case the conversion of position 0
+            // to avoid a crash trying to get the text for that file, since this function
+            // otherwise assumes that 'fileName' is the name of a file that exists.
+            if (position === 0) {
+                return { line: 0, character: 0 };
+            }
+            return sourceMapper.toLineColumnOffset(fileName, position);
+        }
+
         function prepareCallHierarchy(fileName: string, position: number): CallHierarchyItem | CallHierarchyItem[] | undefined {
             synchronizeHostData();
             const declarations = CallHierarchy.resolveCallHierarchyDeclaration(program, getTouchingPropertyName(getValidSourceFile(fileName), position));
@@ -2567,7 +2578,7 @@ namespace ts {
             getAutoImportProvider,
             getApplicableRefactors,
             getEditsForRefactor,
-            toLineColumnOffset: sourceMapper.toLineColumnOffset,
+            toLineColumnOffset,
             getSourceMapper: () => sourceMapper,
             clearSourceMapperCache: () => sourceMapper.clearCache(),
             prepareCallHierarchy,

tests/cases/fourslash/fourslash.ts

@@ -278,6 +278,7 @@ declare namespace FourSlashInterface {
          * `verify.goToDefinition(["a", "aa"], "b");` verifies that markers "a" and "aa" have the same definition "b".
          * `verify.goToDefinition("a", ["b", "bb"]);` verifies that "a" has multiple definitions available.
          */
+        goToDefinition(startMarkerNames: ArrayOrSingle<string>, fileResult: { file: string }): void;
         goToDefinition(startMarkerNames: ArrayOrSingle<string>, endMarkerNames: ArrayOrSingle<string>): void;
         goToDefinition(startMarkerNames: ArrayOrSingle<string>, endMarkerNames: ArrayOrSingle<string>, range: Range): void;
         /** Performs `goToDefinition` for each pair. */

tests/cases/fourslash/server/goToDefinitionScriptImportServer.ts

@@ -0,0 +1,24 @@
+/// <reference path="../fourslash.ts" />
+
+// @filename: /scriptThing.ts
+//// /*1d*/console.log("woooo side effects")
+
+// @filename: /stylez.css
+//// /*2d*/div {
+////   color: magenta;
+//// }
+
+// @filename: /moduleThing.ts
+
+// not a module, but we should let you jump to it.
+//// import [|/*1*/"./scriptThing"|];
+
+// not JS/TS, but if we can, you should be able to jump to it.
+//// import [|/*2*/"./stylez.css"|];
+
+// does not exist, but should return a response to it anyway so an editor can create it.
+//// import [|/*3*/"./foo.txt"|];
+
+verify.goToDefinition("1", "1d");
+verify.goToDefinition("2", "2d");
+verify.goToDefinition("3", { file: "/foo.txt" });