findConfigFile can return undefined (microsoft#20556)

ajafff · mhegazy · commit 7ef541ca1fe2 · 2018-01-04T16:56:29.000-08:00
diff --git a/src/compiler/program.ts b/src/compiler/program.ts
@@ -6,7 +6,7 @@
 namespace ts {
     const ignoreDiagnosticCommentRegEx = /(^\s*$)|(^\s*\/\/\/?\s*(@ts-ignore)?)/;
 
-    export function findConfigFile(searchPath: string, fileExists: (fileName: string) => boolean, configName = "tsconfig.json"): string {
+    export function findConfigFile(searchPath: string, fileExists: (fileName: string) => boolean, configName = "tsconfig.json"): string | undefined {
         return forEachAncestorDirectory(searchPath, ancestor => {
             const fileName = combinePaths(ancestor, configName);
             return fileExists(fileName) ? fileName : undefined;
diff --git a/tests/baselines/reference/api/tsserverlibrary.d.ts b/tests/baselines/reference/api/tsserverlibrary.d.ts
@@ -3770,7 +3770,7 @@ declare namespace ts {
     }
 }
 declare namespace ts {
-    function findConfigFile(searchPath: string, fileExists: (fileName: string) => boolean, configName?: string): string;
+    function findConfigFile(searchPath: string, fileExists: (fileName: string) => boolean, configName?: string): string | undefined;
     function resolveTripleslashReference(moduleName: string, containingFile: string): string;
     function createCompilerHost(options: CompilerOptions, setParentNodes?: boolean): CompilerHost;
     function getPreEmitDiagnostics(program: Program, sourceFile?: SourceFile, cancellationToken?: CancellationToken): Diagnostic[];
diff --git a/tests/baselines/reference/api/typescript.d.ts b/tests/baselines/reference/api/typescript.d.ts
@@ -3717,7 +3717,7 @@ declare namespace ts {
     }
 }
 declare namespace ts {
-    function findConfigFile(searchPath: string, fileExists: (fileName: string) => boolean, configName?: string): string;
+    function findConfigFile(searchPath: string, fileExists: (fileName: string) => boolean, configName?: string): string | undefined;
     function resolveTripleslashReference(moduleName: string, containingFile: string): string;
     function createCompilerHost(options: CompilerOptions, setParentNodes?: boolean): CompilerHost;
     function getPreEmitDiagnostics(program: Program, sourceFile?: SourceFile, cancellationToken?: CancellationToken): Diagnostic[];

Original file line number	Diff line number	Diff line change
`@@ -3770,7 +3770,7 @@ declare namespace ts {`
`3770`	`3770`	`}`
`3771`	`3771`	`}`
`3772`	`3772`	`declare namespace ts {`
`3773`		`- function findConfigFile(searchPath: string, fileExists: (fileName: string) => boolean, configName?: string): string;`
	`3773`	`+ function findConfigFile(searchPath: string, fileExists: (fileName: string) => boolean, configName?: string): string \| undefined;`
`3774`	`3774`	`function resolveTripleslashReference(moduleName: string, containingFile: string): string;`
`3775`	`3775`	`function createCompilerHost(options: CompilerOptions, setParentNodes?: boolean): CompilerHost;`
`3776`	`3776`	`function getPreEmitDiagnostics(program: Program, sourceFile?: SourceFile, cancellationToken?: CancellationToken): Diagnostic[];`
Original file line number	Diff line number	Diff line change
`@@ -3717,7 +3717,7 @@ declare namespace ts {`
`3717`	`3717`	`}`
`3718`	`3718`	`}`
`3719`	`3719`	`declare namespace ts {`
`3720`		`- function findConfigFile(searchPath: string, fileExists: (fileName: string) => boolean, configName?: string): string;`
	`3720`	`+ function findConfigFile(searchPath: string, fileExists: (fileName: string) => boolean, configName?: string): string \| undefined;`
`3721`	`3721`	`function resolveTripleslashReference(moduleName: string, containingFile: string): string;`
`3722`	`3722`	`function createCompilerHost(options: CompilerOptions, setParentNodes?: boolean): CompilerHost;`
`3723`	`3723`	`function getPreEmitDiagnostics(program: Program, sourceFile?: SourceFile, cancellationToken?: CancellationToken): Diagnostic[];`