fix: use METAMASK_ENVIRONMENT instead of NODE_ENV (#22282)

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## **Description**

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also include relevant motivation and context. Have in mind the following
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2. What is the improvement/solution?
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Use metamask enviornment variable instead of node_env to view feature
override dashboard
## **Changelog**

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## **Related issues**

Fixes:

## **Manual testing steps**

```gherkin
Feature: my feature name

  Scenario: user navigates to Feature Flag Override Dashboard in settings
    Given the metamask eviornment is not production

    When user navigates to settings
    Then they will see and navigate to the Feature Flag Override Dashboard
```

## **Screenshots/Recordings**

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### **Before**

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### **After**

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## **Pre-merge author checklist**

- [X] I’ve followed [MetaMask Contributor
Docs](https://github.com/MetaMask/contributor-docs) and [MetaMask Mobile
Coding
Standards](https://github.com/MetaMask/metamask-mobile/blob/main/.github/guidelines/CODING_GUIDELINES.md).
- [X] I've completed the PR template to the best of my ability
- [X] I’ve included tests if applicable
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Not required for external contributors.

## **Pre-merge reviewer checklist**

- [ ] I've manually tested the PR (e.g. pull and build branch, run the
app, test code being changed).
- [ ] I confirm that this PR addresses all acceptance criteria described
in the ticket it closes and includes the necessary testing evidence such
as recordings and or screenshots.

<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> Switches visibility gating from NODE_ENV to METAMASK_ENVIRONMENT for
Feature Flag Override screens and adds tests; also memoizes feature flag
context helpers.
> 
> - **Navigation & Settings**
> - Replace `process.env.NODE_ENV !== 'production'` with
`process.env.METAMASK_ENVIRONMENT !== 'production'` to conditionally
show `Routes.FEATURE_FLAG_OVERRIDE` in `MainNavigator` and the Feature
Flag Override drawer in `Views/Settings`.
> - **Tests**
> - Update `MainNavigator.test.tsx` and `Views/Settings/index.test.tsx`
to use `METAMASK_ENVIRONMENT`, including setup/teardown of env var and
assertions that Feature Flag Override is present in non-production.
> - **Feature Flag Context**
> - Memoize `featureFlagsList`, `getFeatureFlag`, and the provided
context value via `useMemo/useCallback`.
> - Use `process.env.METAMASK_ENVIRONMENT` in minimum version
validation.
> 
> <sup>Written by [Cursor
Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit
1ab6560. This will update automatically
on new commits. Configure
[here](https://cursor.com/dashboard?tab=bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

Author: asalsys

app/components/Nav/Main/MainNavigator.js

@@ -1,4 +1,4 @@
-import React, { useState, useEffect, useMemo, useCallback } from 'react';
+import React, { useState, useEffect, useMemo } from 'react';
 import { Image, StyleSheet, Keyboard, Platform } from 'react-native';
 import { createStackNavigator } from '@react-navigation/stack';
 import { useSelector } from 'react-redux';
@@ -1192,7 +1192,7 @@ const MainNavigator = () => {
           ...GeneralSettings.navigationOptions,
         }}
       />
-      {process.env.NODE_ENV !== 'production' && (
+      {process.env.METAMASK_ENVIRONMENT !== 'production' && (
         <Stack.Screen
           name={Routes.FEATURE_FLAG_OVERRIDE}
           component={FeatureFlagOverride}

app/components/Nav/Main/MainNavigator.test.tsx

@@ -13,10 +13,16 @@ jest.mock('@react-navigation/stack', () => ({
 }));
 
 describe('MainNavigator', () => {
+  const originalEnv = process.env.METAMASK_ENVIRONMENT;
+
   beforeEach(() => {
     jest.clearAllMocks();
   });
 
+  afterEach(() => {
+    process.env.METAMASK_ENVIRONMENT = originalEnv;
+  });
+
   it('matches rendered snapshot', () => {
     // Given the initial app state
     // When rendering the MainNavigator
@@ -60,4 +66,41 @@ describe('MainNavigator', () => {
     expect(sampleFeatureScreen).toBeDefined();
     expect(sampleFeatureScreen?.component.name).toBe('SampleFeatureFlow');
   });
+
+  it('includes FeatureFlagOverride screen when METAMASK_ENVIRONMENT is not production', () => {
+    // Given a non-production environment
+    process.env.METAMASK_ENVIRONMENT = 'dev';
+
+    // When rendering the MainNavigator
+    const container = renderWithProvider(<MainNavigator />, {
+      state: initialRootState,
+    });
+
+    // Then it should contain the FeatureFlagOverride screen
+    interface ScreenChild {
+      name: string;
+      component: { name: string };
+    }
+    const screenProps: ScreenChild[] = container.root.children
+      .filter(
+        (child): child is ReactTestInstance =>
+          typeof child === 'object' &&
+          'type' in child &&
+          'props' in child &&
+          child.type?.toString() === 'Screen',
+      )
+      .map((child) => ({
+        name: child.props.name,
+        component: child.props.component,
+      }));
+
+    const featureFlagOverrideScreen = screenProps?.find(
+      (screen) => screen?.name === Routes.FEATURE_FLAG_OVERRIDE,
+    );
+
+    expect(featureFlagOverrideScreen).toBeDefined();
+    expect(featureFlagOverrideScreen?.component.name).toBe(
+      'FeatureFlagOverride',
+    );
+  });
 });

app/components/Views/Settings/index.test.tsx

@@ -6,6 +6,7 @@ import { SettingsViewSelectorsIDs } from '../../../../e2e/selectors/Settings/Set
 import { backgroundState } from '../../../util/test/initial-root-state';
 import { fireEvent } from '@testing-library/react-native';
 import Routes from '../../../constants/navigation/Routes';
+import { strings } from '../../../../locales/i18n';
 
 // Mock Authentication module
 jest.mock('../../../core', () => ({
@@ -171,4 +172,40 @@ describe('Settings', () => {
     });
     expect(Authentication.lockApp).toHaveBeenCalledTimes(1);
   });
+
+  describe('Feature Flag Override', () => {
+    const originalEnv = process.env.METAMASK_ENVIRONMENT;
+
+    beforeEach(() => {
+      jest.clearAllMocks();
+      // Reset to original value before each test
+      if (originalEnv !== undefined) {
+        process.env.METAMASK_ENVIRONMENT = originalEnv;
+      } else {
+        delete process.env.METAMASK_ENVIRONMENT;
+      }
+    });
+
+    afterEach(() => {
+      if (originalEnv !== undefined) {
+        process.env.METAMASK_ENVIRONMENT = originalEnv;
+      } else {
+        delete process.env.METAMASK_ENVIRONMENT;
+      }
+    });
+
+    it('renders feature flag override drawer when METAMASK_ENVIRONMENT is not production', () => {
+      process.env.METAMASK_ENVIRONMENT = 'development';
+
+      const { getByText } = renderWithProvider(<Settings />, {
+        state: initialState,
+      });
+
+      const featureFlagOverrideTitle = getByText(
+        strings('app_settings.feature_flag_override.title'),
+      );
+
+      expect(featureFlagOverrideTitle).toBeDefined();
+    });
+  });
 });

app/components/Views/Settings/index.tsx

@@ -329,7 +329,7 @@ const Settings = () => {
             onPress={onPressDeveloperOptions}
           />
         )}
-        {process.env.NODE_ENV !== 'production' && (
+        {process.env.METAMASK_ENVIRONMENT !== 'production' && (
           <SettingsDrawer
             title={strings('app_settings.feature_flag_override.title')}
             description={strings(

app/contexts/FeatureFlagOverrideContext.tsx

@@ -139,14 +139,16 @@ export const FeatureFlagOverrideProvider: React.FC<
     getAllOverrides,
   ]);
 
-  const featureFlagsList = Object.values(featureFlags).sort((a, b) =>
-    a.key.localeCompare(b.key),
+  const featureFlagsList = useMemo(
+    () =>
+      Object.values(featureFlags).sort((a, b) => a.key.localeCompare(b.key)),
+    [featureFlags],
   );
 
   const validateMinimumVersion = useCallback(
     (flagKey: string, flagValue: MinimumVersionFlagValue) => {
       if (
-        process.env.NODE_ENV !== 'production' &&
+        process.env.METAMASK_ENVIRONMENT !== 'production' &&
         !isMinimumRequiredVersionSupported(flagValue.minimumVersion)
       ) {
         toastRef?.current?.showToast({
@@ -172,42 +174,62 @@ export const FeatureFlagOverrideProvider: React.FC<
   /**
    * get a specific feature flag value with overrides applied
    */
-  const getFeatureFlag = (key: string) => {
-    const flag = featureFlags[key];
-    if (!flag) {
-      return undefined;
-    }
-
-    if (flag.type === 'boolean with minimumVersion') {
-      return validateMinimumVersion(
-        flag.key,
-        flag.value as unknown as MinimumVersionFlagValue,
-      );
-    }
-
-    return flag.value;
-  };
+  const getFeatureFlag = useCallback(
+    (key: string) => {
+      const flag = featureFlags[key];
+      if (!flag) {
+        return undefined;
+      }
+
+      if (flag.type === 'boolean with minimumVersion') {
+        return validateMinimumVersion(
+          flag.key,
+          flag.value as unknown as MinimumVersionFlagValue,
+        );
+      }
+
+      return flag.value;
+    },
+    [featureFlags, validateMinimumVersion],
+  );
 
   const getOverrideCount = useCallback(
     (): number => Object.keys(overrides).length,
     [overrides],
   );
 
-  const contextValue: FeatureFlagOverrideContextType = {
-    featureFlags,
-    originalFlags: rawFeatureFlags,
-    getFeatureFlag,
-    featureFlagsList,
-    overrides,
-    setOverride,
-    removeOverride,
-    clearAllOverrides,
-    hasOverride,
-    getOverride,
-    getAllOverrides,
-    applyOverrides,
-    getOverrideCount,
-  };
+  const contextValue: FeatureFlagOverrideContextType = useMemo(
+    () => ({
+      featureFlags,
+      originalFlags: rawFeatureFlags,
+      getFeatureFlag,
+      featureFlagsList,
+      overrides,
+      setOverride,
+      removeOverride,
+      clearAllOverrides,
+      hasOverride,
+      getOverride,
+      getAllOverrides,
+      applyOverrides,
+      getOverrideCount,
+    }),
+    [
+      featureFlags,
+      rawFeatureFlags,
+      getFeatureFlag,
+      featureFlagsList,
+      overrides,
+      setOverride,
+      removeOverride,
+      clearAllOverrides,
+      hasOverride,
+      getOverride,
+      getAllOverrides,
+      applyOverrides,
+      getOverrideCount,
+    ],
+  );
 
   return (
     <FeatureFlagOverrideContext.Provider value={contextValue}>