CODEGEN-834 - [cli] Handle partial generation success (#10376)

* Add writeOnPartialSuccess flag to partially write successful generateiong

* Update config name from writeOnPartialSuccess to allowPartialOutputs

* Ensure consistent experience on complete failure, update tests

* Restructure code and comment

* Update website schema

* Update doc

Author: eddeee888

.changeset/many-pets-attend.md

@@ -0,0 +1,6 @@
+---
+'@graphql-codegen/plugin-helpers': minor
+'@graphql-codegen/cli': major
+---
+
+Add `allowPartialOutputs` flag to partially write successful generation to files

packages/graphql-codegen-cli/src/codegen.ts

@@ -69,7 +69,9 @@ function createCache(): <T>(namespace: string, key: string, factory: () => Promi
   };
 }
 
-export async function executeCodegen(input: CodegenContext | Types.Config): Promise<Types.FileOutput[]> {
+export async function executeCodegen(
+  input: CodegenContext | Types.Config
+): Promise<{ result: Types.FileOutput[]; error: Error | null }> {
   const context = ensureContext(input);
   const config = context.getConfig();
   const pluginContext = context.getPluginContext();
@@ -431,13 +433,13 @@ export async function executeCodegen(input: CodegenContext | Types.Config): Prom
     printLogs();
   }
 
+  let error: Error | null = null;
   if (executedContext.errors.length > 0) {
     const errors = executedContext.errors.map(subErr => subErr.message || subErr.toString());
-    const newErr = new AggregateError(executedContext.errors, String(errors.join('\n\n')));
+    error = new AggregateError(executedContext.errors, String(errors.join('\n\n')));
     // Best-effort to all stack traces for debugging
-    newErr.stack = `${newErr.stack}\n\n${executedContext.errors.map(subErr => subErr.stack).join('\n\n')}`;
-    throw newErr;
+    error.stack = `${error.stack}\n\n${executedContext.errors.map(subErr => subErr.stack).join('\n\n')}`;
   }
 
-  return result;
+  return { result, error };
 }

packages/graphql-codegen-cli/src/generate-and-save.ts

@@ -1,12 +1,14 @@
 import { createHash } from 'crypto';
 import { dirname, isAbsolute, join } from 'path';
+import logSymbols from 'log-symbols';
 import { Types } from '@graphql-codegen/plugin-helpers';
 import { executeCodegen } from './codegen.js';
 import { CodegenContext, ensureContext } from './config.js';
 import { lifecycleHooks } from './hooks.js';
 import { debugLog } from './utils/debugging.js';
 import { mkdirp, readFile, unlinkFile, writeFile } from './utils/file-system.js';
 import { createWatcher } from './utils/watcher.js';
+import { getLogger } from './utils/logger.js';
 
 const hash = (content: string): string => createHash('sha1').update(content).digest('base64');
 
@@ -133,7 +135,27 @@ export async function generate(
     return createWatcher(context, writeOutput).runningWatcher;
   }
 
-  const outputFiles = await context.profiler.run(() => executeCodegen(context), 'executeCodegen');
+  const { result: outputFiles, error } = await context.profiler.run(() => executeCodegen(context), 'executeCodegen');
+
+  if (error) {
+    // If all generation failed, just throw to return non-zero code.
+    if (outputFiles.length === 0) {
+      throw error;
+    }
+
+    // If partial success, but partial output is not allowed, throw to return non-zero code.
+    if (!config.allowPartialOutputs) {
+      getLogger().error(
+        `  ${logSymbols.error} One or more errors occurred, no files were generated. To allow output on errors, set config.allowPartialOutputs=true`
+      );
+      throw error;
+    }
+
+    // If partial success, and partial output is allowed, warn and proceed to write to files.
+    getLogger().warn(
+      `  ${logSymbols.warning} One or more errors occurred, some files were generated. To prevent any output on errors, set config.allowPartialOutputs=false`
+    );
+  }
 
   await context.profiler.run(() => writeOutput(outputFiles), 'writeOutput');
   await context.profiler.run(() => lifecycleHooks(config.hooks).beforeDone(), 'Lifecycle: beforeDone');

packages/graphql-codegen-cli/src/utils/watcher.ts

@@ -78,7 +78,10 @@ export const createWatcher = (
     const debouncedExec = debounce(() => {
       if (!isShutdown) {
         executeCodegen(initialContext)
-          .then(onNext, () => Promise.resolve())
+          .then(
+            ({ result }) => onNext(result),
+            () => Promise.resolve()
+          )
           .then(() => emitWatching(watchDirectory));
       }
     }, 100);
@@ -198,7 +201,10 @@ export const createWatcher = (
    */
   stopWatching.runningWatcher = new Promise<void>((resolve, reject) => {
     executeCodegen(initialContext)
-      .then(onNext, () => Promise.resolve())
+      .then(
+        ({ result }) => onNext(result),
+        () => Promise.resolve()
+      )
       .then(() => runWatcher(abortController.signal))
       .catch(err => {
         watcherSubscription.unsubscribe();