fix(codegen): use deepmerge for CLI config merging

Replace manual spread operators with deepmerge (via mergeConfig) for
merging file config with CLI options. This ensures nested objects like
db.pgpm are properly deep-merged rather than overwritten.

Also restores filterDefined in buildDbConfig to prevent undefined CLI
values from interfering with file config during merge.

Author: pyramation

graphql/codegen/src/cli/index.ts

@@ -9,7 +9,7 @@ import { CLI, CLIOptions, getPackageJson, Inquirerer } from 'inquirerer';
 
 import { findConfigFile, loadConfigFile } from '../core/config';
 import { generate } from '../core/generate';
-import type { GraphQLSDKConfigTarget } from '../types/config';
+import { mergeConfig, type GraphQLSDKConfigTarget } from '../types/config';
 import {
   buildDbConfig,
   buildGenerateOptions,
@@ -114,10 +114,9 @@ export const commands = async (
       let hasError = false;
       for (const name of names) {
         console.log(`\n[${name}]`);
-        const result = await generate({
-          ...targets[name],
-          ...cliOptions,
-        } as GraphQLSDKConfigTarget);
+        const result = await generate(
+          mergeConfig(targets[name], cliOptions as GraphQLSDKConfigTarget),
+        );
         printResult(result);
         if (!result.success) hasError = true;
       }

graphql/codegen/src/cli/shared.ts

@@ -9,7 +9,7 @@ import { inflektTree } from 'inflekt/transform-keys';
 import type { Question } from 'inquirerer';
 
 import type { GenerateResult } from '../core/generate';
-import type { GraphQLSDKConfigTarget } from '../types/config';
+import { mergeConfig, type GraphQLSDKConfigTarget } from '../types/config';
 
 export const splitCommas = (
   input: string | undefined,
@@ -202,7 +202,10 @@ export function buildDbConfig(
 ): Record<string, unknown> {
   const { schemas, apiNames, ...rest } = options;
   if (schemas || apiNames) {
-    return { ...rest, db: { schemas, apiNames } };
+    return {
+      ...rest,
+      db: filterDefined({ schemas, apiNames } as Record<string, unknown>),
+    };
   }
   return rest;
 }
@@ -259,5 +262,5 @@ export function buildGenerateOptions(
   const camelized = camelizeArgv(answers);
   const normalized = normalizeCodegenListOptions(camelized);
   const withDb = buildDbConfig(normalized);
-  return { ...fileConfig, ...withDb } as GraphQLSDKConfigTarget;
+  return mergeConfig(fileConfig, withDb as GraphQLSDKConfigTarget);
 }