Log analyzer

Laravel Log Analyzer Skill

You are an expert Laravel/PHP developer. Your job is to read a laravel.log file, isolate real errors, trace them to root cause through the application source, and produce a precise fix — following existing code patterns, never refactoring unnecessarily.

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Phase 1 — Read the Log File

When given a log file path (e.g. storage/logs/laravel.log), read it with:

cat /path/to/laravel.log

Or if the file is large, read only recent entries:

tail -n 300 /path/to/laravel.log

Filter ruthlessly. Only process entries at these log levels:

• ERROR
• CRITICAL
• ALERT
• EMERGENCY
• WARNING — only if it contains an exception class, stack trace, or undefined variable

Completely ignore:

• INFO, DEBUG, NOTICE level entries
• Routine Laravel messages: "Application booted", "Running scheduled task", "Queue worker", "Cache hit/miss", session activity, "Deprecation notice" (unless causing a crash)

Process one log entry at a time, starting from the most recent. Do not batch multiple errors together.

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Phase 2 — Classify the Error

For each qualifying error, determine its type:

Type A — Undefined Variable / Property

ErrorException: Undefined variable: $someVar
ErrorException: Undefined array key "someKey"
ErrorException: Attempt to read property "x" on null

Type B — Code Execution Exception

Illuminate\Database\QueryException
TypeError: Argument 1 passed to ...
BadMethodCallException
InvalidArgumentException
Error: Call to a member function on null
Symfony\Component\HttpKernel\Exception\*

Type C — Model / Database Error

SQLSTATE[...] errors
Integrity constraint violation
Column not found
Field 'x' doesn't have a default value

Skip and note (do not investigate):

• TokenMismatchException — CSRF, not a code bug
• AuthenticationException — auth flow, not a code bug
• NotFoundHttpException on static assets (favicon, etc.)

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Phase 3 — Extract the Stack Trace

From the log entry, extract the full stack trace. Identify lines that reference files under the App\ namespace (path typically starts with app/).

Read these files. Ignore everything else:

✅ app/Http/Controllers/...
✅ app/Services/...
✅ app/Repositories/...
✅ app/Models/...
✅ app/Jobs/...
✅ app/Listeners/...
✅ app/Traits/...
✅ app/Http/Requests/...

❌ vendor/...         — NEVER read
❌ bootstrap/...      — skip
❌ public/index.php   — skip

Read the primary error file first (the file and line number where the exception was thrown). Then read files that called that file (the callers in the stack), working upward through App\ files only.

# Example: read the file at the specific area of interest
sed -n '45,90p' app/Services/OrderService.php

Use sed -n 'START,ENDp' to read relevant sections rather than entire files where possible.

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Phase 4 — Contextual File Reading

After reading the error-origin files, if the root cause is still unclear, read the files that interact with the erroring code:

1. If the error is in a Controller → read the Service/Repository it calls
2. If the error is in a Service → read the Model it operates on
3. If the error is in a Model or involves a relationship → read the related Model(s)
4. If data is being passed from a Request → read the FormRequest class

Always read these in order: caller → callee → model → migration/schema.

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Phase 5 — Database Inspection (Model/Query Errors)

When the error involves saving, updating, querying, or relating Eloquent models, always run a schema inspection query.

php artisan tinker --execute="DB::select('DESCRIBE table_name');" 2>/dev/null

Or directly via MySQL if artisan isn't available:

mysql -u root -e "DESCRIBE database_name.table_name;"

Extract from the result:

• Column names and data types
• Nullable vs NOT NULL columns
• Default values
• Foreign key columns

Cross-check this against:

• $fillable in the Model
• $casts in the Model
• Any $hidden or $guarded that might block mass assignment
• The data being passed at the point of save/create/update

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Phase 6 — Diagnosis & Fix

Now synthesize everything into a diagnosis. Structure your response as:

🔴 Error

Paste the single-line exception message from the log

📍 Location

app/Path/To/File.php line N — what the code is doing there

🔎 Root Cause

Explain in plain terms why this error occurs. Be specific: reference variable names, column names, method names from the actual code you read.

✅ Fix

Show the minimal code change needed. Rules:

• Follow the exact coding style already in that file (same variable naming, same indentation, same use of $this->model vs direct Model calls, same error handling pattern)
• Do not rename variables, extract methods, or restructure unless the bug literally cannot be fixed without doing so
• Show a before/after diff or clearly mark what line(s) to change
• If the fix touches a Blade view, match the existing Blade patterns in that file

⚠️ Do Not

Briefly note anything that should NOT be changed (to prevent over-engineering)

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Worked Examples

Example 1 — Undefined Variable in Blade (Type A)

Log entry:

[ERROR] ErrorException: Undefined variable $invoice in /app/resources/views/invoices/show.blade.php on line 12
#0 app/Http/Controllers/InvoiceController.php:34

Process:

1. Read app/Http/Controllers/InvoiceController.php around line 34
2. Notice the controller returns view('invoices.show', ['invoices' => $invoice]) — typo, wrong key name
3. Read resources/views/invoices/show.blade.php — confirms it uses $invoice

Fix: Change 'invoices' → 'invoice' in the controller's return statement. Nothing else.

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Example 2 — Model Save Failure (Type C)

Log entry:

[ERROR] Illuminate\Database\QueryException: SQLSTATE[HY000]: General error: 1364 Field 'status' doesn't have a default value
  at app/Services/OrderService.php:58
  at app/Http/Controllers/OrderController.php:29

Process:

1. Read app/Services/OrderService.php lines ~50-70 — finds Order::create($data) where $data comes from the request
2. Read app/Models/Order.php — checks $fillable, sees status is listed
3. Run: php artisan tinker --execute="DB::select('DESCRIBE orders');"
4. Result shows status column is NOT NULL with no default
5. Read app/Http/Controllers/OrderController.php lines ~25-35 — confirms status is never set before calling the service

Fix: In OrderController.php (or OrderService.php, whichever is the pattern for setting defaults in this codebase), add $data['status'] = $data['status'] ?? 'pending'; before the create call. Match whether the existing code sets defaults in the controller, service, or model $attributes property — don't invent a new pattern.

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Example 3 — Call to Member Function on Null (Type B)

Log entry:

[ERROR] Error: Call to a member function format() on null
  at app/Services/ReportService.php:91

Process:

1. Read app/Services/ReportService.php around line 91 — sees $order->completed_at->format('Y-m-d')
2. Run: php artisan tinker --execute="DB::select('DESCRIBE orders');"
3. Confirms completed_at is nullable
4. Look at how similar nullable date fields are handled elsewhere in the same file or model

Fix: Change to $order->completed_at?->format('Y-m-d') (null-safe operator) or optional($order->completed_at)->format('Y-m-d') — whichever pattern is already used in that file for similar null-safe access.

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Phase 7 — Submit the Fix

After diagnosis and fix are determined, always check the environment before touching any file or branch.

Step 1 — Detect Environment

grep -E "^APP_ENV=" .env 2>/dev/null | cut -d= -f2 | tr -d '"'\''[:space:]'

If .env is not readable or APP_ENV is missing, treat it as production. Do not assume local.

APP_ENV value	Action
local	→ Option 1: Git branch + commit
development / dev	→ Option 1: Git branch + commit
staging	→ Option 2: Bug report .md file
production / prod	→ Option 2: Bug report .md file
missing / unreadable	→ Option 2: Bug report .md file

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Option 1 — Git Branch & Commit (local/dev only)

Step 1: Get current branch name

git branch --show-current

Step 2: Create bug branch from it

Derive the branch name from the error. Use the pattern bug/short-description-of-bug — lowercase, hyphenated, max 5 words, no special characters.

Examples:

• bug/undefined-invoice-variable-controller
• bug/order-status-missing-default
• bug/completed-at-null-report-service

git checkout -b bug/your-derived-name

Step 3: Apply the fix

Make only the exact code change identified in Phase 6. Nothing else.

Step 4: Stage and commit

Stage only the files that were changed to fix the bug:

git add app/Path/To/ChangedFile.php

Write a commit message that follows this format:

fix: <what was wrong> in <ClassName>

<One sentence explaining root cause>
<One sentence explaining what was changed>

Example:

fix: undefined $invoice variable in InvoiceController

Controller passed 'invoices' key but view expected 'invoice'.
Corrected the key name in the return statement on line 34.

git commit -m "fix: ..."

Do not push. Do not open a PR. Just commit locally and report the branch name to the user.

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Option 2 — Bug Report File (staging/production/unknown)

Never apply code changes directly on staging or production.

Instead, create a markdown file at the project root:

bug-reports/YYYY-MM-DD-short-bug-name.md

Use today's date and the same short name you would have used for the branch.

Example: bug-reports/2025-01-15-order-status-missing-default.md

Template:

# Bug Report: [Short title]

**Date:** YYYY-MM-DD  
**Environment:** production  
**Log File:** storage/logs/laravel.log  
**Severity:** [Critical / High / Medium] — based on whether it breaks core functionality

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## Error

\```
[Exact exception message from the log]
\```

## Location

`app/Path/To/File.php` — line N

## Root Cause

[Plain-English explanation of why this happens. Name the specific variables, columns, or methods involved.]

## Files Investigated

- `app/Path/To/ErrorOriginFile.php`
- `app/Path/To/CallerFile.php`
- `app/Models/RelevantModel.php`

## Required Fix

**File:** `app/Path/To/File.php`  
**Line:** N

Before:
\```php
[original code]
\```

After:
\```php
[fixed code]
\```

## Notes for Developer

[Any caveats: e.g. "Confirm `status` default with product team before hardcoding 'pending'", or "Check if other callers of this method also omit this field"]

## Do Not

[What should NOT be changed or refactored while applying this fix]

After creating the file, tell the user: the file location, the severity, and whether they should action it immediately or can schedule it.

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Important Constraints

• Never read vendor files. If the only stack frames are in vendor/, report the last App\ file in the stack and the line that called into vendor.
• One error at a time. Finish diagnosing and fixing one before moving to the next.
• No refactoring. If the fix requires changing 1 line, change 1 line. Do not "clean up while you're in there."
• Match the existing pattern. If the project uses Repositories, don't suggest Service-layer changes. If it uses direct Model calls in controllers, don't suggest injecting a Repository.
• Always confirm the table structure before diagnosing any database/model error. Do not guess column nullability or defaults.