Error map
Uncaught Exception Fatal error: Uncaught Exception: message in file.php:12
PHP · layer 4, Application & API
Centre: this error. First ring: errors it is linked with (12). Outer ring: what those are linked with. Colours show the layer of a request each error belongs to. Click any dot to re-centre the map on it; hover to follow its connections. The centre dot opens the error page.
Directly related (12)
HTTP 500 Internal Server Error
The server hit an unexpected condition — usually an unhandled exception or misconfiguration in the application.
Thread 1: signal SIGABRT (app crashes with "libc++abi: terminating")
The app deliberately aborted — an uncaught exception, failed assertion or fatalError. The console above the crash has the real me…
PHP Fatal error: Uncaught Error: Call to undefined function
PHP can’t find the function you called — usually a missing extension, missing include, or namespace issue.
System.InvalidCastException: Unable to cast object of type 'X' to type 'Y'
An explicit cast failed because the object’s runtime type isn’t the target type.
java.lang.IllegalStateException
A method was called when the object wasn’t in the right state for it.
Fatal error: Uncaught Error: Call to a member function x() on null
Code called a method on a variable that is null instead of an object.
Fatal error: Uncaught ArgumentCountError: Too few arguments to function foo(), 1 passed and exactly 2 expected
A function was called with fewer arguments than it requires.
Fatal error: Cannot redeclare function foo() (previously declared in …)
The same function (or class) was defined twice — usually a file included more than once.
C++: terminate called after throwing an instance of 'std::out_of_range' — what(): vector::_M_range_check
A C++ exception wasn’t caught anywhere, so std::terminate aborted the program. what() tells you the reason.
PHP Fatal error: Allowed memory size of X bytes exhausted
The script tried to use more memory than PHP’s `memory_limit` allows.
java.util.NoSuchElementException: No value present
Code asked for an element that doesn’t exist — Optional.get() on empty, iterator.next() past the end, Scanner with no input.
Fatal error: Uncaught Error: Cannot use object of type stdClass as array
Code used array syntax (`$x['key']`) on an object.
Two steps away (36)
HTTP 404 Not Found
The server can’t find anything at the requested URL.
HTTP 502 Bad Gateway
A proxy or gateway (Nginx, load balancer, CDN) got an invalid response — or no response — from the upstream server behind it.
HTTP 503 Service Unavailable
The server is temporarily unable to handle the request — overloaded, in maintenance, or has no healthy backends.
Fatal error: Unexpectedly found nil while unwrapping an Optional value
Swift force-unwrapped (`!`) an optional that was nil, crashing the app.
java.lang.IllegalArgumentException
A method rejected an argument value as invalid.
java.lang.ArithmeticException: / by zero
Integer division or modulo by zero.
PHP Fatal error: Uncaught Error: Class "X" not found
PHP couldn’t load the class — autoloading failed, the namespace is wrong, or the dependency isn’t installed.
Warning: Cannot modify header information - headers already sent
You called `header()`, `setcookie()` or `session_start()` after output had already been sent to the browser.
WordPress: There Has Been a Critical Error on This Website
A PHP fatal error (usually from a plugin or theme) stopped WordPress; the real error is in the debug log or recovery-mode email.
AttributeError: 'X' object has no attribute 'y'
You accessed an attribute or method that doesn’t exist on that object type.
java.lang.ClassCastException: class A cannot be cast to class B
An object was cast to a type it isn’t.
TypeError [ERR_INVALID_ARG_TYPE]: The "path" argument must be of type string. Received undefined
A Node API got an argument of the wrong type — usually undefined because an env var or config value is missing.
HTTP 409 Conflict
The request conflicts with the current state of the resource — e.g. a duplicate or an edit based on an outdated version.
TypeError: Cannot assign to read only property 'x' of object
Code tried to modify a frozen object, a getter-only property, or immutable state.
Warning: Cannot update a component (`Parent`) while rendering a different component (`Child`)
A child component updated a parent’s state during its render instead of in an effect or event handler.
System.NullReferenceException: Object reference not set to an instance of an object
Code dereferenced a variable that is `null` — the .NET equivalent of Java’s NullPointerException.
PHP Fatal error: Maximum execution time of 30 seconds exceeded
The script ran longer than `max_execution_time` and PHP stopped it.
PHP Parse error: syntax error, unexpected …
PHP can’t parse the file because of a syntax mistake — the real error is often on the line before the one reported.
Fatal error: Uncaught TypeError: foo(): Argument #1 ($x) must be of type int, string given
A function received a value of the wrong type for a typed parameter.
Fatal error: Uncaught DivisionByZeroError: Division by zero
Code divided by zero (or used modulo by zero) — PHP 8 throws instead of warning.
Fatal error: Uncaught mysqli_sql_exception
A MySQLi query or connection failed; since PHP 8.1 MySQLi throws exceptions by default.
Warning: include(x.php): Failed to open stream: No such file or directory
PHP couldn’t open a file for include/require/fopen — wrong path, missing file, or no permission.
Fatal error: Maximum function nesting level of '256' reached, aborting!
Recursion went deeper than Xdebug’s max_nesting_level allows (or PHP crashed with a segfault without Xdebug).
WordPress: Plugin could not be activated because it triggered a fatal error
Activating the plugin caused a PHP fatal error — usually PHP version incompatibility, a conflict with another plugin/theme, or mi…
Segmentation fault (core dumped)
A program accessed memory it wasn’t allowed to, and the kernel killed it with SIGSEGV (exit code 139).
FATAL: the database system is in recovery mode
PostgreSQL crashed (often OOM-killed) and is replaying WAL to recover.
Illegal instruction (core dumped) (SIGILL)
The program used a CPU instruction your processor doesn’t support — typically AVX/AVX2 in prebuilt binaries (TensorFlow, MongoDB…
Kubernetes: OOMKilled (exit code 137)
The container used more memory than its limit, and the kernel killed it.
HTTP 413 Content Too Large (Request Entity Too Large)
The request body is bigger than the server is willing to accept — usually a file upload over the configured limit.
java.lang.OutOfMemoryError: Java heap space
The JVM ran out of heap memory and garbage collection couldn’t free enough.
InvalidOperationException: Sequence contains no elements / more than one element
LINQ `First()`, `Single()`, `Last()` or `Max()` ran on an empty sequence (or `Single()` found several items).
java.nio.file.AccessDeniedException: /path
The OS denied a file operation to the Java process.
ArgumentOutOfRangeException: Index was out of range. Must be non-negative and less than the size of the collection
Code accessed a List/collection position that doesn’t exist (IndexOutOfRangeException for arrays).
Warning: Array to string conversion
An array was used where a string is expected — echoing it, concatenating it, or passing it to a string function.
Fatal error: Uncaught TypeError: Unsupported operand types: string + int
An arithmetic or array operator was used with incompatible types (PHP 8 is stricter than PHP 7).
Deprecated: Implicit conversion from float 2.5 to int loses precision
PHP 8.1+ warns when a float with a fractional part is silently converted to int (array keys, % operator, int parameters).
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