Fix default configured project crash with disableReferecedProjectLoad (microsoft#2639)

Author: gabritto

internal/project/projectcollection.go

@@ -185,7 +185,8 @@ func (c *ProjectCollection) findDefaultConfiguredProjectWorker(path tspath.Path,
 			if project.CommandLine == nil {
 				return nil
 			}
-			return core.Map(project.CommandLine.ResolvedProjectReferencePaths(), func(configFileName string) *Project {
+			// A referenced project may not be loaded if `disableReferencedProjectLoad` is true.
+			return core.MapNonNil(project.CommandLine.ResolvedProjectReferencePaths(), func(configFileName string) *Project {
 				return c.configuredProjects[c.toPath(configFileName)]
 			})
 		},

internal/project/projectcollectiondefaultproject_test.go

@@ -0,0 +1,128 @@
+package project_test
+
+import (
+	"context"
+	"testing"
+
+	"github.com/microsoft/typescript-go/internal/bundled"
+	"github.com/microsoft/typescript-go/internal/lsp/lsproto"
+	"github.com/microsoft/typescript-go/internal/testutil/projecttestutil"
+)
+
+func TestProjectCollectionDefaultProject(t *testing.T) {
+	t.Parallel()
+
+	if !bundled.Embedded {
+		t.Skip("bundled files are not embedded")
+	}
+
+	// Project 1 references project 2, which does not have open files.
+	// File project1/dist/index.d.ts does not belong to any tsconfig.json, but is included in programs for
+	// projects 3 and 4 via project 1's output.
+	// When looking for a default project for project1/dist/index.d.ts,
+	// we should not try to unconditionally access project 2,
+	// which isn't loaded because of `disableReferencedProjectLoad`.
+	files := map[string]any{
+		"/project1/tsconfig.json": `{
+			"extends": "../tsconfig.json",
+			"files": [],
+			"include": ["src/**/*"],
+			"references": [
+				{
+					"path": "../project2"
+				}
+			],
+			"compilerOptions": {
+				"composite": true,
+				"outDir": "./dist",
+				"rootDir": "./src",
+			}
+		}`,
+		"/project1/src/index.ts": `export const foo = 42;
+		export type Bar = { a: string };`,
+		"/project1/dist/index.d.ts": `export declare const foo = 42;
+			export type Bar = {
+				a: string;
+			};`,
+		"/project2/tsconfig.json": `{
+			"extends": "../tsconfig.json",
+			"files": [],
+			"include": ["src/**/*"],
+			"compilerOptions": {
+				"composite": true,
+				"outDir": "./dist",
+				"rootDir": "./src"
+			}
+		}`,
+		"/project3/tsconfig.json": `{
+			"extends": "../tsconfig.json",
+			"files": [],
+			"include": ["src/**/*"],
+			"references": [
+				{
+					"path": "../project1"
+				}
+			],
+			"compilerOptions": {
+				"composite": true,
+				"outDir": "./dist",
+				"rootDir": "./src",
+			}
+		}`,
+		"/project3/src/index.ts": `import { Bar } from "../../project1/dist/index.js";
+			declare const b: Bar;
+			const x: string = b.a;`,
+		"/project4/tsconfig.json": `{
+			"extends": "../tsconfig.json",
+			"files": [],
+			"include": ["src/**/*"],
+			"references": [
+				{
+					"path": "../project1"
+				}
+			],
+			"compilerOptions": {
+				"composite": true,
+				"outDir": "./dist",
+				"rootDir": "./src",
+			}
+		}`,
+		"/project4/src/index.ts": `import { Bar } from "../../project1/dist/index.js";
+declare const b: Bar;
+const x: string = b.a;`,
+		"/tsconfig.json": `{
+			"compilerOptions": {
+				"disableReferencedProjectLoad": true,
+				"disableSolutionSearching": true,
+				"disableSourceOfProjectReferenceRedirect": true
+			},
+			"files": [],
+			"references": [
+				{
+					"path": "./project1"
+				},
+				{
+					"path": "./project2"
+				},
+				{
+					"path": "./project3"
+				},
+				{
+					"path": "./project4"
+				}
+			]
+		}`,
+	}
+	uris := []lsproto.DocumentUri{
+		"file:///project1/dist/index.d.ts",
+		"file:///project1/src/index.ts",
+		"file:///project3/src/index.ts",
+		"file:///project4/src/index.ts",
+	}
+	session, _ := projecttestutil.Setup(files)
+	// Should not crash.
+	for _, uri := range uris {
+		content := files[string(uri)[7:]].(string)
+		session.DidOpenFile(context.Background(), uri, 1, content, lsproto.LanguageKindTypeScript)
+	}
+}