More checks for utilities

Author: ardatan

packages/federation/src/supergraph.ts

@@ -70,6 +70,7 @@ import {
   visitWithTypeInfo,
 } from 'graphql';
 import {
+  extractPercentageFromLabel,
   filterInternalFieldsAndTypes,
   getArgsFromKeysForFederation,
   getCacheKeyFnFromKey,
@@ -1297,16 +1298,8 @@ export function getStitchingOptionsFromSupergraphSdl(
           }
 
           const label = fieldInfo.label;
-          // Extract 10 from percent(10) for example
-          const percentRegexp = /^percent\((\d+(?:\.\d+)?)\)$/;
-          const match = percentRegexp.exec(label);
-          if (match) {
-            const percent = Number(match[1]);
-            if (percent < 0 || percent > 100) {
-              throw new Error(
-                `Invalid progressive override percent value for field ${typeName}.${fieldInfo.field} in subgraph ${subgraphName}: ${label}`,
-              );
-            }
+          const percent = extractPercentageFromLabel(label);
+          if (percent != null) {
             const possibility = percent / 100;
             fieldConfig.override = () =>
               progressiveOverridePossibilityHandler(possibility);

packages/federation/src/utils.ts

@@ -250,3 +250,25 @@ export const progressiveOverridePossibilityHandler = (possibility: number) => {
   const rng = Math.random();
   return rng < possibility;
 };
+
+export function extractPercentageFromLabel(label: string): number | undefined {
+  if (label.startsWith('percent(') && label.endsWith(')')) {
+    const regexp = /^percent\((\d+(?:\.\d+)?)\)$/;
+    const match = regexp.exec(label);
+    const percentageStr = match?.[1];
+    if (!percentageStr) {
+      throw new Error(`Expected a number in percent(x), got: ${label}`);
+    }
+    const parsedFloat = parseFloat(percentageStr);
+    if (isNaN(parsedFloat)) {
+      throw new Error(`Could not parse percentage value from label: ${label}`);
+    }
+    if (parsedFloat < 0 || parsedFloat > 100) {
+      throw new Error(
+        `Expected a percentage value between 0 and 100, got ${parsedFloat}`,
+      );
+    }
+    return parsedFloat;
+  }
+  return undefined;
+}

packages/federation/tests/progressive-override.test.ts

@@ -3,6 +3,7 @@ import { normalizedExecutor } from '@graphql-tools/executor';
 import { parse } from 'graphql';
 import { describe, expect, it } from 'vitest';
 import { getStitchedSchemaFromLocalSchemas } from './getStitchedSchemaFromLocalSchemas';
+import { extractPercentageFromLabel } from '@graphql-tools/federation';
 
 describe('Progressive Override', () => {
   describe('Label processing', () => {
@@ -287,4 +288,29 @@ describe('Progressive Override', () => {
       });
     });
   });
+  describe('percent(x) parsing', () => {
+    it('support integers', () => {
+      expect(extractPercentageFromLabel('percent(10)')).toBe(10);
+    });
+    it('support floats', () => {
+      expect(extractPercentageFromLabel('percent(12.5)')).toBe(12.5);
+    });
+    it('returns undefined for non-matching labels', () => {
+      expect(extractPercentageFromLabel('custom_label')).toBeUndefined();
+      expect(extractPercentageFromLabel('percentile(10)')).toBeUndefined();
+    });
+    it('throws for out-of-bound numbers', () => {
+      expect(() => extractPercentageFromLabel('percent(150)')).toThrowError(
+        'Expected a percentage value between 0 and 100, got 150',
+      );
+    });
+    it('throws for malformed percent labels', () => {
+      expect(() => extractPercentageFromLabel('percent()')).toThrowError(
+        'Expected a number in percent(x), got: percent()',
+      );
+      expect(() => extractPercentageFromLabel('percent(foo)')).toThrowError(
+        'Expected a number in percent(x), got: percent(foo)',
+      );
+    });
+  });
 });