From 456a6bf658b25d559d3eadc9e9ea04aaa5faf7f4 Mon Sep 17 00:00:00 2001
From: Klaus Meinhardt <klaus.meinhardt1@gmail.com>
Date: Sat, 3 Jun 2017 00:10:41 +0200
Subject: [PATCH 1/2] program.getSourceFile[ByPath] can return undefined

---
 src/compiler/program.ts | 4 ++--
 src/compiler/types.ts   | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/compiler/program.ts b/src/compiler/program.ts
index 834122b358..d481e72b68 100644
--- a/src/compiler/program.ts
+++ b/src/compiler/program.ts
@@ -969,11 +969,11 @@ namespace ts {
             return emitResult;
         }
 
-        function getSourceFile(fileName: string): SourceFile {
+        function getSourceFile(fileName: string): SourceFile | undefined {
             return getSourceFileByPath(toPath(fileName, currentDirectory, getCanonicalFileName));
         }
 
-        function getSourceFileByPath(path: Path): SourceFile {
+        function getSourceFileByPath(path: Path): SourceFile | undefined {
             return filesByName.get(path);
         }
 
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index ed1d5dcbe2..da438809d9 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -2352,8 +2352,8 @@ namespace ts {
 
     export interface ScriptReferenceHost {
         getCompilerOptions(): CompilerOptions;
-        getSourceFile(fileName: string): SourceFile;
-        getSourceFileByPath(path: Path): SourceFile;
+        getSourceFile(fileName: string): SourceFile | undefined;
+        getSourceFileByPath(path: Path): SourceFile | undefined;
         getCurrentDirectory(): string;
     }
 

From b75ccb1c49f3ed42e819fd741c8f2655d571a593 Mon Sep 17 00:00:00 2001
From: Klaus Meinhardt <klaus.meinhardt1@gmail.com>
Date: Sun, 22 Oct 2017 23:01:23 +0200
Subject: [PATCH 2/2] accept baselines

---
 tests/baselines/reference/api/tsserverlibrary.d.ts | 4 ++--
 tests/baselines/reference/api/typescript.d.ts      | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/tests/baselines/reference/api/tsserverlibrary.d.ts b/tests/baselines/reference/api/tsserverlibrary.d.ts
index 62f4f68d14..9769a9b1a7 100644
--- a/tests/baselines/reference/api/tsserverlibrary.d.ts
+++ b/tests/baselines/reference/api/tsserverlibrary.d.ts
@@ -1592,8 +1592,8 @@ declare namespace ts {
     }
     interface ScriptReferenceHost {
         getCompilerOptions(): CompilerOptions;
-        getSourceFile(fileName: string): SourceFile;
-        getSourceFileByPath(path: Path): SourceFile;
+        getSourceFile(fileName: string): SourceFile | undefined;
+        getSourceFileByPath(path: Path): SourceFile | undefined;
         getCurrentDirectory(): string;
     }
     interface ParseConfigHost {
diff --git a/tests/baselines/reference/api/typescript.d.ts b/tests/baselines/reference/api/typescript.d.ts
index c7c8ba88d7..f185ef0dae 100644
--- a/tests/baselines/reference/api/typescript.d.ts
+++ b/tests/baselines/reference/api/typescript.d.ts
@@ -1592,8 +1592,8 @@ declare namespace ts {
     }
     interface ScriptReferenceHost {
         getCompilerOptions(): CompilerOptions;
-        getSourceFile(fileName: string): SourceFile;
-        getSourceFileByPath(path: Path): SourceFile;
+        getSourceFile(fileName: string): SourceFile | undefined;
+        getSourceFileByPath(path: Path): SourceFile | undefined;
         getCurrentDirectory(): string;
     }
     interface ParseConfigHost {