Add a new "explain" logger

CHANGELOG.md

@@ -10,11 +10,15 @@ Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
 
+### Changed
+
+- When running in watch mode, a persistent service will now restart on each run if it does not have a `files` field in its config. This makes persistent services better match the behavior of standard scripts and ephemeral services.
+
 ### Added
 
 - Added a new logger for debugging your Wireit configs. Set `WIREIT_LOGGER=explain` to see detailed information about why each script is run, as well as the normal `simple` logs, without any stdout or stderr of scripts.
 
-- Added more "why" information to the `simple` and `metrics` loggers as well, including why a service was restarted, and what file change triggered a new run in watch mode.
+- Added more "why" explanations to the `simple` and `metrics` loggers as well, including why a service was restarted, and what file change triggered a new run in watch mode.
 
 ### Fixed
 

README.md

@@ -554,7 +554,7 @@ the given regular expression.
 
 In watch mode, a service will be restarted whenever one of its input files or
 dependencies change, except for dependencies with
-[`cascade`](#execution-cascade) set to `false`. Unlike standard scripts, `wireit` assumes that a service doesn't depend on any files unless you tell it otherwise by defining a `files` array.
+[`cascade`](#execution-cascade) set to `false`.
 
 ### Service output
 

src/fingerprint.ts

@@ -209,16 +209,16 @@ export class Fingerprint {
       if (script.command === undefined) {
         return undefined;
       }
+      if (script.files === undefined) {
+        return {name: 'no files field'};
+      }
       // A service. Always fully tracked. No 'files' means that we
       // assume that it writes no files. Can't produce output.
       if (script.service !== undefined) {
         return undefined;
       }
       // A standard script. Fully tracked if we know both its inputs and
       // outputs.
-      if (script.files === undefined) {
-        return {name: 'no files field'};
-      }
       if (script.output === undefined) {
         return {name: 'no output field'};
       }

src/logging/default-logger.ts

@@ -373,15 +373,13 @@ export class DefaultLogger implements Logger {
             );
           }
           case 'dependency not fully tracked': {
-            return `the service depends on [${labelForScript(
+            return `it depends on [${labelForScript(
               this.rootPackageDir,
               stringToScriptReference(notFullyTrackedReason.dependency),
             )}] which must always be run`;
           }
           case 'no files field': {
-            throw new Error(
-              'Internal error: a service is tracked even without a files field',
-            );
+            return `it has no 'files' field`;
           }
           case 'no output field': {
             throw new Error('Internal error: a service never has output');

src/test/gc.test.ts

@@ -74,6 +74,7 @@ async function retryWithGcUntilCallbackDoesNotThrow(
   cb: () => void,
 ): Promise<void> {
   for (const wait of [0, 10, 100, 500, 1000]) {
+    collectGarbage();
     collectGarbage();
     try {
       cb();
@@ -251,10 +252,12 @@ test(
           servicePersistent: {
             command: servicePersistent.command,
             service: true,
+            files: [],
           },
           serviceEphemeral: {
             command: serviceEphemeral.command,
             service: true,
+            files: [],
           },
         },
       },

src/test/service.test.ts

@@ -649,6 +649,7 @@ for (const failureMode of ['continue', 'no-new']) {
             },
             service: {
               command: service.command,
+              files: [],
               service: true,
             },
             standard: {
@@ -833,10 +834,12 @@ test(
           service1: {
             command: service1.command,
             dependencies: ['service2'],
+            files: [],
             service: true,
           },
           service2: {
             command: service2.command,
+            files: [],
             service: true,
           },
           standard: {
@@ -849,9 +852,7 @@ test(
 
     await rig.write('input', '0');
     const wireit = rig.exec('npm run entrypoint --watch');
-    await wireit.waitForLog(
-      /67% \[2 \/ 3\] \[3 running\] \[2 services\] standard/,
-    );
+    await wireit.waitForLog(/67% \[2 \/ 3\] \[3 running\] \[2 services\]/);
 
     // Iteration 1
     {
@@ -1146,6 +1147,7 @@ test(
           service: {
             command: service.command,
             service: true,
+            files: [],
             dependencies: [
               'hard',
               {
@@ -1413,7 +1415,7 @@ test(
     await wireit.waitForLog(/\[standard\] Executed successfully/);
     await service.nextInvocation();
     await wireit.waitForLog(
-      /\[service\] Service stopped because the service depends on \[standard\] which must always be run/,
+      /\[service\] Service stopped because it depends on \[standard\] which must always be run/,
     );
     await wireit.waitForLog(/\[service\] Service starting.../);
     await wireit.waitForLog(/\[service\] Service ready/);

vscode-extension/package.json

@@ -43,6 +43,7 @@
         "..:build"
       ],
       "files": [
+        ".tsbuildinfo",
         "tsconfig.json",
         "src/**/*.ts"
       ],