refactor(migrations): avoid TS error 18003 when no files found (angular#57899)

cexbrayat · pkozlowski-opensource · commit eb77b533b89c · 2024-09-23T12:42:33.000+02:00
When running a migration, tsurge creates a TS program from the tsconfig files found. This can result in a 18003 error when no files are found (based on the includes/files of the config). For example, the signal input migration throws in a CLI project that has no spec files: ``` ng g @angular/core:signal-inputs --defaults Tsconfig could not be parsed or is invalid: No inputs were found in config file '/tsconfig.spec.json'. Specified 'include' paths were '["src/**/*.spec.ts","src/**/*.d.ts"]' and 'exclude' paths were '["/out-tsc/spec"]'. ``` A similar issue has already been raised in the CDK migration (see angular/components#27055). This was solved in the CDK (credits to @crisbeto) by ignoring the 18003 error (see 9c1112d408361a47c98dfd470b8e990cbd1753db). This PR does the same in tsurge. PR Close angular#57899
diff --git a/packages/core/schematics/utils/tsurge/helpers/ngtsc_program.ts b/packages/core/schematics/utils/tsurge/helpers/ngtsc_program.ts
@@ -17,9 +17,12 @@ import {
 import {NgtscProgram} from '@angular/compiler-cli/src/ngtsc/program';
 import {BaseProgramInfo} from '../program_info';
 
+/** Code of the error raised by TypeScript when a tsconfig doesn't match any files. */
+const NO_INPUTS_ERROR_CODE = 18003;
+
 /**
  * Parses the configuration of the given TypeScript project and creates
- * an instance of the Angular compiler for for the project.
+ * an instance of the Angular compiler for the project.
  */
 export function createNgtscProgram(
   absoluteTsconfigPath: string,
@@ -33,10 +36,13 @@ export function createNgtscProgram(
 
   const tsconfig = readConfiguration(absoluteTsconfigPath, {}, fs);
 
-  if (tsconfig.errors.length > 0) {
+  // Skip the "No inputs found..." error since we don't want to interrupt the migration if a
+  // tsconfig doesn't match a file. This will result in an empty `Program` which is still valid.
+  const errors = tsconfig.errors.filter((diag) => diag.code !== NO_INPUTS_ERROR_CODE);
+
+  if (errors.length) {
     throw new Error(
-      `Tsconfig could not be parsed or is invalid:\n\n` +
-        `${tsconfig.errors.map((e) => e.messageText)}`,
+      `Tsconfig could not be parsed or is invalid:\n\n` + `${errors.map((e) => e.messageText)}`,
     );
   }
 
