fix(transformers): use symbols for additionalProperties key variables

Replace literal string 'key' with plugin.symbol('key') in the
additionalProperties for-loop generation. This ensures the planner
assigns unique names (key, key2, key3, ...) when nested or sibling
additionalProperties produce multiple for-loops, preventing the
TypeScript error caused by duplicate variable names in nested scopes.

Closes #3838

Author: pullfrog[bot]

packages/openapi-ts-tests/main/test/__snapshots__/3.1.x/transformers-additional-properties/transformers.gen.ts

@@ -13,9 +13,9 @@ const barSchemaResponseTransformer = (data: any) => {
         data.baz[key] = fooSchemaResponseTransformer(data.baz[key]);
     }
     if (data.qux) {
-        for (const key of Object.keys(data.qux)) {
-            if (!['quux'].includes(key)) {
-                data.qux[key] = new Date(data.qux[key]);
+        for (const key2 of Object.keys(data.qux)) {
+            if (!['quux'].includes(key2)) {
+                data.qux[key2] = new Date(data.qux[key2]);
             }
         }
     }

packages/openapi-ts/src/plugins/@hey-api/transformers/plugin.ts

@@ -195,16 +195,17 @@ function processSchemaType({
     }
 
     if (schema.additionalProperties && dataExpression) {
+      const key = plugin.symbol('key');
       const entryValueNodes = processSchemaType({
-        dataExpression: $(dataExpression).attr('key').computed(),
+        dataExpression: $(dataExpression).attr(key).computed(),
         plugin,
         schema: schema.additionalProperties,
       });
 
       if (entryValueNodes.length) {
         const properties = Object.keys(schema.properties ?? {});
         nodes.push(
-          $.for($.const('key'))
+          $.for($.const(key))
             .of($('Object').attr('keys').call(dataExpression))
             .$if(
               properties.length,
@@ -214,7 +215,7 @@ function processSchemaType({
                     $.not(
                       $.array(...properties)
                         .attr('includes')
-                        .call('key'),
+                        .call(key),
                     ),
                   ).do(...entryValueNodes),
                 ),