Check extended tsconfig time with oldest output time to report not upto date

Author: sheetalkamat

src/compiler/tsbuild.ts

@@ -794,14 +794,12 @@ namespace ts {
             }
             else {
                 // Check tsconfig time
-                const tsconfigTime = host.getModifiedTime(project.options.configFilePath!) || missingFileModifiedTime;
-                if (oldestOutputFileTime < tsconfigTime) {
-                    return {
-                        type: UpToDateStatusType.OutOfDateWithSelf,
-                        outOfDateOutputFileName: oldestOutputFileName,
-                        newerInputFileName: project.options.configFilePath!
-                    };
-                }
+                const configStatus = checkConfigFileUpToDateStatus(project.options.configFilePath!, oldestOutputFileTime, oldestOutputFileName);
+                if (configStatus) return configStatus;
+
+                // Check extended config time
+                const extendedConfigStatus = forEach(project.options.configFile!.extendedSourceFiles || emptyArray, configFile => checkConfigFileUpToDateStatus(configFile, oldestOutputFileTime, oldestOutputFileName));
+                if (extendedConfigStatus) return extendedConfigStatus;
             }
 
             if (!buildInfoChecked.hasKey(project.options.configFilePath as ResolvedConfigFileName)) {
@@ -839,6 +837,18 @@ namespace ts {
             };
         }
 
+        function checkConfigFileUpToDateStatus(configFile: string, oldestOutputFileTime: Date, oldestOutputFileName: string): Status.OutOfDateWithSelf | undefined {
+            // Check tsconfig time
+            const tsconfigTime = host.getModifiedTime(configFile) || missingFileModifiedTime;
+            if (oldestOutputFileTime < tsconfigTime) {
+                return {
+                    type: UpToDateStatusType.OutOfDateWithSelf,
+                    outOfDateOutputFileName: oldestOutputFileName,
+                    newerInputFileName: configFile
+                };
+            }
+        }
+
         function invalidateProject(configFileName: string, reloadLevel?: ConfigFileProgramReloadLevel) {
             invalidateResolvedProject(resolveProjectName(configFileName), reloadLevel);
         }

src/testRunner/unittests/tsbuild/sample.ts

@@ -282,6 +282,37 @@ namespace ts {
                     [Diagnostics.Updating_unchanged_output_timestamps_of_project_0, "/src/tests/tsconfig.json"]
                 );
             });
+
+            it("rebuilds when extended config file changes", () => {
+                const fs = projFs.shadow();
+                fs.writeFileSync("/src/tests/tsconfig.base.json", JSON.stringify({ compilerOptions: { target: "es3" } }));
+                replaceText(fs, "/src/tests/tsconfig.json", `"references": [`, `"extends": "./tsconfig.base.json", "references": [`);
+                const host = new fakes.SolutionBuilderHost(fs);
+                const builder = createSolutionBuilder(host, ["/src/tests"], { verbose: true });
+                builder.buildAllProjects();
+                host.assertDiagnosticMessages(
+                    getExpectedDiagnosticForProjectsInBuild("src/core/tsconfig.json", "src/logic/tsconfig.json", "src/tests/tsconfig.json"),
+                    [Diagnostics.Project_0_is_out_of_date_because_output_file_1_does_not_exist, "src/core/tsconfig.json", "src/core/anotherModule.js"],
+                    [Diagnostics.Building_project_0, "/src/core/tsconfig.json"],
+                    [Diagnostics.Project_0_is_out_of_date_because_output_file_1_does_not_exist, "src/logic/tsconfig.json", "src/logic/index.js"],
+                    [Diagnostics.Building_project_0, "/src/logic/tsconfig.json"],
+                    [Diagnostics.Project_0_is_out_of_date_because_output_file_1_does_not_exist, "src/tests/tsconfig.json", "src/tests/index.js"],
+                    [Diagnostics.Building_project_0, "/src/tests/tsconfig.json"]
+                );
+                host.clearDiagnostics();
+                tick();
+                builder.resetBuildContext();
+                fs.writeFileSync("/src/tests/tsconfig.base.json", JSON.stringify({ compilerOptions: {} }));
+                builder.buildAllProjects();
+                host.assertDiagnosticMessages(
+                    getExpectedDiagnosticForProjectsInBuild("src/core/tsconfig.json", "src/logic/tsconfig.json", "src/tests/tsconfig.json"),
+                    [Diagnostics.Project_0_is_up_to_date_because_newest_input_1_is_older_than_oldest_output_2, "src/core/tsconfig.json", "src/core/anotherModule.ts", "src/core/anotherModule.js"],
+                    [Diagnostics.Project_0_is_up_to_date_because_newest_input_1_is_older_than_oldest_output_2, "src/logic/tsconfig.json", "src/logic/index.ts", "src/logic/index.js"],
+                    [Diagnostics.Project_0_is_out_of_date_because_oldest_output_1_is_older_than_newest_input_2, "src/tests/tsconfig.json", "src/tests/index.js", "src/tests/tsconfig.base.json"],
+                    [Diagnostics.Building_project_0, "/src/tests/tsconfig.json"],
+                    [Diagnostics.Updating_unchanged_output_timestamps_of_project_0, "/src/tests/tsconfig.json"]
+                );
+            });
         });
 
         describe("downstream-blocked compilations", () => {