Salesforce Apex Quality

# Salesforce Apex Quality Guardrails

Apply these checks to every Apex class, trigger, and test file you write or review.

## Step 1 — Governor Limit Safety Check

Scan for these patterns before declaring any Apex file acceptable:

### SOQL and DML in Loops — Automatic Fail

```apex
// ❌ NEVER — causes LimitException at scale
for (Account a : accounts) {
    List<Contact> contacts = [SELECT Id FROM Contact WHERE AccountId = :a.Id]; // SOQL in loop
    update a; // DML in loop
}

// ✅ ALWAYS — collect, then query/update once
Set<Id> accountIds = new Map<Id, Account>(accounts).keySet();
Map<Id, List<Contact>> contactsByAccount = new Map<Id, List<Contact>>();
for (Contact c : [SELECT Id, AccountId FROM Contact WHERE AccountId IN :accountIds]) {
    if (!contactsByAccount.containsKey(c.AccountId)) {
        contactsByAccount.put(c.AccountId, new List<Contact>());
    }
    contactsByAccount.get(c.AccountId).add(c);
}
update accounts; // DML once, outside the loop
```

Rule: if you see `[SELECT` or `Database.query`, `insert`, `update`, `delete`, `upsert`, `merge` inside a `for` loop body — stop and refactor before proceeding.

## Step 2 — Sharing Model Verification

Every class must declare its sharing intent explicitly. Undeclared sharing inherits from the caller — unpredictable behaviour.

| Declaration | When to use |
|---|---|
| `public with sharing class Foo` | Default for all service, handler, selector, and controller classes |
| `public without sharing class Foo` | Only when the class must run elevated (e.g. system-level logging, trigger bypass). Requires a code comment explaining why. |
| `public inherited sharing class Foo` | Framework entry points that should respect the caller's sharing context |

If a class does not have one of these three declarations, **add it before writing anything else**.

## Step 3 — CRUD / FLS Enforcement

Apex code that reads or writes records on behalf of a user must verify object and field access. The platform does **not** enforce FLS or CRUD automatically in Apex.

```apex
// Check before querying a field
if (!Schema.sObjectType.Contact.fields.Email.isAccessible()) {
    throw new System.NoAccessException();
}

// Or use WITH USER_MODE in SOQL (API 56.0+)
List<Contact> contacts = [SELECT Id, Email FROM Contact WHERE AccountId = :accId WITH USER_MODE];

// Or use Database.query with AccessLevel
List<Contact> contacts = Database.query('SELECT Id, Email FROM Contact', AccessLevel.USER_MODE);
```

Rule: any Apex method callable from a UI component, REST endpoint, or `@InvocableMethod` **must** enforce CRUD/FLS. Internal service methods called only from trusted contexts may use `with sharing` instead.

## Step 4 — SOQL Injection Prevention

```apex
// ❌ NEVER — concatenates user input into SOQL string
String soql = 'SELECT Id FROM Account WHERE Name = \'' + userInput + '\'';

// ✅ ALWAYS — bind variable
String soql = [SELECT Id FROM Account WHERE Name = :userInput];

// ✅ For dynamic SOQL with user-controlled field names — validate against a whitelist
Set<String> allowedFields = new Set<String>{'Name', 'Industry', 'AnnualRevenue'};
if (!allowedFields.contains(userInput)) {
    throw new IllegalArgumentException('Field not permitted: ' + userInput);
}
```

## Step 5 — Modern Apex Idioms

Prefer current language features (API 62.0 / Winter '25+):

| Old pattern | Modern replacement |
|---|---|
| `if (obj != null) { x = obj.Field__c; }` | `x = obj?.Field__c;` |
| `x = (y != null) ? y : defaultVal;` | `x = y ?? defaultVal;` |
| `System.assertEquals(expected, actual)` | `Assert.areEqual(expected, actual)` |
| `System.assert(condition)` | `Assert.isTrue(condition)` |
| `[SELECT ... WHERE ...]` with no sharing context | `[SELECT ... WHERE ... WITH USER_MODE]` |

## Step 6 — PNB Test Coverage Checklist

Every feature must be tested across all three paths. Missing any one of these is a quality failure:

### Positive Path
- Expected input → expected output.
- Assert the exact field values, record counts, or return values — not just that no exception was thrown.

### Negative Path
- Invalid input, null values, empty collections, and error conditions.
- Assert that exceptions are thrown with the correct type and message.
- Assert that no records were mutated when the operation should have failed cleanly.

### Bulk Path
- Insert/update/delete **200–251 records** in a single test transaction.
- Assert that all records processed correctly — no partial failures from governor limits.
- Use `Test.startTest()` / `Test.stopTest()` to isolate governor limit counters for async work.

### Test Class Rules
```apex
@isTest(SeeAllData=false)   // Required — no exceptions without a documented reason
private class AccountServiceTest {

    @TestSetup
    static void makeData() {
        // Create all test data here — use a factory if one exists in the project
    }

    @isTest
    static void givenValidInput_whenProcessAccounts_thenFieldsUpdated() {
        // Positive path
        List<Account> accounts = [SELECT Id FROM Account LIMIT 10];
        Test.startTest();
        AccountService.processAccounts(accounts);
        Test.stopTest();
        // Assert meaningful outcomes — not just no exception
        List<Account> updated = [SELECT Status__c FROM Account WHERE Id IN :accounts];
        Assert.areEqual('Processed', updated[0].Status__c, 'Status should be Processed');
    }
}
```

## Step 7 — Trigger Architecture Checklist

- [ ] One trigger per object. If a second trigger exists, consolidate into the handler.
- [ ] Trigger body contains only: context checks, handler invocation, and routing logic.
- [ ] No business logic, SOQL, or DML directly in the trigger body.
- [ ] If a trigger framework (Trigger Actions Framework, ff-apex-common, custom base class) is already in use — extend it. Do not create a parallel pattern.
- [ ] Handler class is `with sharing` unless the trigger requires elevated access.

## Quick Reference — Hardcoded Anti-Patterns Summary

| Pattern | Action |
|---|---|
| SOQL inside `for` loop | Refactor: query before the loop, operate on collections |
| DML inside `for` loop | Refactor: collect mutations, DML once after the loop |
| Class missing sharing declaration | Add `with sharing` (or document why `without sharing`) |
| `escape="false"` on user data (VF) | Remove — auto-escaping enforces XSS prevention |
| Empty `catch` block | Add logging and appropriate re-throw or error handling |
| String-concatenated SOQL with user input | Replace with bind variable or whitelist validation |
| Test with no assertion | Add a meaningful `Assert.*` call |
| `System.assert` / `System.assertEquals` style | Upgrade to `Assert.isTrue` / `Assert.areEqual` |
| Hardcoded record ID (`'001...'`) | Replace with queried or inserted test record ID |