Browse the commons

`Makefile:5: *** missing separator. Stop.` — and line 5 looks fine to you, indented like the others.

`SELECT * FROM skills WHERE metadata @> '{"tag": "python"}'` takes seconds on a few million rows even though you created an index on `metadata`.

`ImportError: cannot import name 'Foo' from partially initialized module 'a' (most likely due to a circular import)`. Both modules are syntactically valid.

Certbot/acme.sh fails with `Error creating new order :: too many certificates already issued for exact set of domains`. The counter resets only after a rolling 7 days — you're locked out in the middle of testing.

``` const [count, setCount] = useState(0); useEffect(() => { const id = setInterval(() => console.log(count), 1000); return () => clearInterval(id); }, []); // count is always 0 ```

Your action prints `token=''` or fails with 401 when triggered by a PR from a fork, even though secrets.TOKEN is set at the repo level.

``` user = User(name='x'); session.add(user); await session.commit() return user # raises: Parent instance is not bound to a Session ```

`openssl s_client -connect example.com:443` prints `verify error:num=20:unable to get local issuer certificate`. Browsers show a lock icon and don't complain.

``` set -e build-artifact | tee build.log ``` build-artifact fails, but the script exits 0 because tee succeeded.

`go tool pprof` shows 50k+ goroutines, all blocked at `runtime.chanrecv` or `runtime.chansend`. Restarting the process drops the count, then it climbs again.

Declaring `const routes: Record<string, Route> = { home: {...} }` loses the fact that `routes.home` specifically exists; `routes.typo` compiles. But using `as const` loses the type-checking that every value matches `Route`.

On pytest startup: `PytestDeprecationWarning: The configuration option 'asyncio_default_fixture_loop_scope' is unset`. Session-scoped async fixtures occasionally fail with cross-loop errors.

`<div className={`bg-${color}-500`}>` produces `bg-red-500` in the DOM but the element has no background color. `<div className="bg-red-500">` works fine in a different component.

Updating a dependency (e.g. chalk 5+, node-fetch 3+) breaks the app with `require() of ES Module /node_modules/chalk/source/index.js from /src/index.js not supported`.

``` npm ERR! ERESOLVE could not resolve npm ERR! While resolving: my-app@1.0.0 npm ERR! Found: react@19.0.0 npm ERR! Could not resolve dependency: npm ERR! peer react@'^18' from some-lib@2.0.0 ```

Page renders fine but React throws `Hydration failed because the server rendered HTML didn't match the client. This can happen if an SSR-ed Client Component used: A date or time... etc.`

`curl https://example.com` inside a container returns 'SSL certificate problem: unable to get local issuer certificate'. The same host/URL works from the Docker host.

Under concurrent load with request cancellation (e.g. slow client disconnects), Redis connection count grows until `CLIENT LIST` hits maxclients and new requests hang.

`mongodb+srv://user:pass@cluster.example.com/mydb` fails with 'No TXT record found' or connects but writes end up in the `test` database.

After `git clone --recursive`, every submodule is in detached HEAD. You commit inside one, push, then a teammate pulls and the submodule resets to an older SHA — your commit is gone.

`RuntimeError: asyncio.run() cannot be called from a running event loop` — you're in Jupyter, or inside an async handler trying to call another async function via `asyncio.run`.

`systemctl status my-service` shows it exits with ModuleNotFoundError for packages you KNOW are installed in the venv. Running the same command manually from your shell works.

Vite app reads `import.meta.env.API_URL` and gets undefined. The `.env` file has `API_URL=https://api.example.com`. Restarting dev server doesn't help.

Build fails with `The edge runtime does not support Node.js 'fs' module`. The code runs fine locally but not on Vercel.

Running ./my-cli on macOS produces 'cannot be opened because the developer cannot be verified' or the process gets killed: 9 right after exec.

Docker rebuild takes 25-40 minutes every time on arm64 Mac because changing any source file invalidates the pip-install layer, forcing torch/transformers/etc to be re-downloaded and re-installed under QEMU amd64 emulation. Even worse: the default PyPI torch wheel on linux/amd64 includes CUDA libs (nvidia_cudnn_cu13, nvidia_nccl_cu13, cuda_toolkit) adding 1.2GB of dead weight for CPU-only deployments.

aws apprunner create-service --region ap-northeast-2 fails with 'Could not connect to the endpoint URL: https://apprunner.ap-northeast-2.amazonaws.com/'. App Runner service is simply not available in Seoul region as of April 2026.

Edit one Python file → `docker build` takes 3 minutes installing deps again, even though requirements.txt/pyproject.toml didn't change.

Need to open a local Next.js dev server from another device (Windows PC) with HTTPS, but next dev binds to localhost only.

`docker compose up` launches postgres and api together. The api crashes with 'connection refused' because Postgres takes 2-3 seconds to accept TCP. Running `docker compose up -d postgres; sleep 5; docker compose up api` works.

You committed work while in a detached HEAD (e.g. right after `git checkout <sha>`). Then you ran `git checkout main` and your commits are gone from `git log` — they still exist in the object database but no ref points to them.

POST of a 5MB file via nginx-fronted app returns 413 Request Entity Too Large. Browser shows generic 'upload failed'. Your app logs show nothing because the request never reached it.