Error map
RecursionError RecursionError: maximum recursion depth exceeded
Python · layer 4, Application & API
Centre: this error. First ring: errors it is linked with (8). 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 (8)
ConnectionRefusedError: [Errno 111] Connection refused
Nothing is listening on the host/port Python tried to connect to.
AttributeError: 'X' object has no attribute 'y'
You accessed an attribute or method that doesn’t exist on that object type.
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).
RangeError: Maximum call stack size exceeded
A function called itself (directly or indirectly) too many times — usually infinite recursion.
java.lang.StackOverflowError
The thread’s call stack overflowed — almost always unbounded recursion, sometimes a bidirectional toString/equals/JSON cycle.
RuntimeError: Event loop is closed
Async code tried to use an event loop that has already been shut down.
Msg 530: The statement terminated. The maximum recursion 100 has been exhausted before statement completion. / MySQL 3636 Recursive query aborted after 1001 iterations
A recursive CTE exceeded the database’s recursion limit — often an infinite loop in hierarchical data.
.NET: Stack overflow. / Process is terminated due to StackOverflowException
Infinite or very deep recursion exhausted the thread’s stack; .NET can’t catch it and terminates the process.
Two steps away (22)
Error: connect ECONNREFUSED 127.0.0.1:5432
Nothing is listening at that host:port — the target service is down or you’re connecting to the wrong address.
Cloudflare Error 521: Web Server Is Down
Cloudflare couldn’t connect to your origin — the connection was refused.
API Request Timed Out (ETIMEDOUT / ReadTimeout / timeout of 30000ms exceeded)
The client gave up waiting — either for the connection to open or for the response to arrive.
TypeError: x is not a function
You called something as a function, but its value is not a function (it’s undefined, a string, an object…).
ImportError: cannot import name 'x' from 'y'
The module was found, but the name you’re importing from it doesn’t exist — usually a version change or a circular import.
KeyError: 'x'
You accessed a dictionary key that doesn’t exist.
PHP Fatal error: Allowed memory size of X bytes exhausted
The script tried to use more memory than PHP’s `memory_limit` allows.
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.
Fatal error: Cannot redeclare function foo() (previously declared in …)
The same function (or class) was defined twice — usually a file included more than once.
Error: Too many re-renders. React limits the number of renders to prevent an infinite loop.
A state update runs during render, which triggers another render, which updates state again — forever.
JsonException: A possible object cycle was detected
System.Text.Json found a reference loop (e.g. Order → Customer → Orders → …) while serialising, usually from EF Core navigation p…
Segmentation fault (core dumped)
A program accessed memory it wasn’t allowed to, and the kernel killed it with SIGSEGV (exit code 139).
java.lang.OutOfMemoryError: Java heap space
The JVM ran out of heap memory and garbage collection couldn’t free enough.
Node.js: [UnhandledPromiseRejection] — This error originated either by throwing inside of an async function without a catch block
A promise rejected and nothing handled it; since Node 15 this crashes the process.
SyntaxError: await is only valid in async functions and the top level bodies of modules
await was used inside a function that isn’t async (or in a classic, non-module script).
AbortError: The user aborted a request. / signal is aborted without reason
A fetch was cancelled through an AbortController (or the browser cancelled it).
Column must appear in the GROUP BY clause / isn't in GROUP BY (MySQL 1055 only_full_group_by)
You selected a column that is neither grouped nor aggregated, so the result would be ambiguous.
ERROR: aggregate functions are not allowed in WHERE (use HAVING) / MySQL 1111 Invalid use of group function
An aggregate (SUM, COUNT, AVG) was used in WHERE, which filters rows before grouping.
MySQL ERROR 1136 (21S01): Column count doesn't match value count at row 1
An INSERT supplies a different number of values than columns.
Illegal instruction (core dumped) (SIGILL)
The program used a CPU instruction your processor doesn’t support — typically AVX/AVX2 in prebuilt binaries (TensorFlow, MongoDB…
The application was unable to start correctly (0xc0000142)
A DLL the program loads failed to initialise — often after an update, with corrupt runtimes, or when a desktop heap/session limit…
System.OutOfMemoryException: Exception of type 'System.OutOfMemoryException' was thrown
The process couldn’t allocate memory — large in-memory data, leaks, 32-bit process limits, or container memory limits.
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