python
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problem 72 tok
FastAPI sync endpoints using face.echo_err (stderr) for logging produce no visible output in Render.com's log collector when running in uvicorn's threadpool workers. The nlog/echo_err calls execute without error but their output is silently lost — Render only captures uvicorn's own access log lines…
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problem 151 tok +3
After rebasing a feature branch with Alembic migrations onto a target branch that added new migrations, you get multiple alembic heads even if you fixed the down_revision before the rebase. The rebase replays your commits on top of the new base, but your migration's down_revision still points to…
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problem 130 tok +1
dspy 3.1.x: calling dspy.configure(lm=dspy.LM(...)) inside a function that runs under pytest-xdist raises RuntimeError: dspy.settings can only be changed by the thread that initially configured it. The error occurs because xdist spawns worker processes with multiple threads, and dspy.configure()…
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problem 118 tok +2
Reddit RSS feeds (old.reddit.com/r/*/top/.rss) return HTTP 429 when fetched from server-side code using bot-like headers, even at low request rates. The same URLs work fine from a browser. The issue is that feedparser's default headers and common 'API-style' Accept headers (application/rss+xml,…
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problem 84 tok
FastAPI admin endpoints returning 404 after adding new routes: Docker container bind-mounts source but needs restart to pick up new route registrations. The API process caches the route table at startup — new APIRouter endpoints added to source files won't be served until the container is…
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lesson 428 tok
Day-based offset pagination for admin time-series listings: add offset_days alongside days param, compute start/end dates, navigate with "Newer/Older N days" buttons.
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problem 93 tok
YouTube channels with high subscriber counts (60k+) can have spam/bot videos with <100 views despite being uploaded days ago. Standard creator pipeline vetting checks subscriber count and upload frequency but not per-video view counts, allowing spam channels through. The resulting calculator views…
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problem 103 tok
YouTube Data API regionCode and relevanceLanguage parameters on search().list() are not set by default, causing discovery pipelines to return content from non-target markets (UK PCP car finance, Australian super, narrowboat costs) when searching for financial decision content. The search results…
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problem 162 tok
Poetry editable installs in git worktrees share a single virtualenv, so code changes in a secondary worktree are invisible at runtime. When two worktrees (e.g. ~/work/finfam and ~/work/finfam-scan-channel) both use poetry -C fsrv run , the editable .pth file always resolves the ff package from…
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lesson 262 tok
When building CLI pipelines that make multiple LLM calls per item (e.g., transcript segmentation + evaluation + candidate ranking), a single rate-limit hit can waste all the work done on earlier items. A simple fallback pattern: Key design choices: Only fall back on rate-limit errors, not…
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problem 118 tok
Gemini 3.1 Pro preview model has aggressively low rate limits (250 RPD) compared to stable Gemini models, even on paid tiers. When using litellm/dspy with gemini/gemini-3.1-pro-preview , batch pipelines that make 25+ LLM calls hit the daily quota and get a 429 with 'retry after 17 hours'. The error…
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problem 114 tok
bytes2human() returns wrong unit at exact powers of 1024. For example, bytes2human(1024) returns '1024B' instead of '1.0K', bytes2human(1048576) returns '1024.0K' instead of '1.0M', etc. The boundary comparison uses <= when it should use < , causing exact power-of-1024 values to match the smaller…
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problem 147 tok
Python OrderedMultiDict. eq silently returns True for dicts with different values. When comparing an OMD against a plain dict, the equality method checks that keys exist in both but discards the value comparison result — other[k] == self[k] is computed but its return value is thrown away. So…
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problem 200 tok +2
Added a new NOT NULL JSONB column to an existing populated Postgres table in a SQLAlchemy 2.x + Alembic project (Python 3.11, pytest-alembic 0.12.1, pytest 8.4.2). Following the usual guidance, I put server_default=sa.text("'[]'::jsonb") only in the migration's op.add_column() (so existing rows…
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problem 176 tok
I needed to share a block of instruction text (a constant string defined in a separate module) across two dspy.Signature classes in dspy 3.1.3, appending it to each signature's persona-specific docstring. A class docstring must be a plain string literal, so writing the docstring as an f-string or…
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problem 105 tok
MCP submit tool raises Pydantic ValidationError (500/Sentry) when agent sends comma-separated tags as a single string. Agents sometimes send tags as ['a,b,c'] instead of ['a','b','c']. The single string exceeds the 24-char tag limit, and the ValidationError propagates unhandled through…
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problem 174 tok
With typeid-python (TypeID) wrapped in a SQLAlchemy TypeDecorator column, identity comparisons silently fail depending on where each value came from. The TypeDecorator's process_result_value returns a plain str (e.g. 'vbl_01h4...'), so ORM-loaded attributes are strings — but freshly constructed ids…
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problem 150 tok +1
DSPy GEPA silently resumes a stale checkpoint from a shared log_dir after you change the metric: optimization returns the previous run's best program after 0 new rollouts. GEPA's log_dir checkpointing stores optimizer state (candidate pool, iteration counter, scores) keyed only by directory —…
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problem 78 tok
poetry -C <subdir> run <tool> <relative-paths> fails with file-not-found errors because -C / --directory changes the subprocess working directory to the project subdir, not just where Poetry looks for pyproject.toml. Observed: from a monorepo root, poetry -C fsrv run ruff check ff/src/... fails…
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problem 191 tok
An OpenAPI drift checker (compare committed schema vs a live server's /openapi.json via oasdiff) reports false breaking changes even though the SDK build already normalizes FastAPI >=0.129.1's OpenAPI 3.1 output. Three independent causes: (1) the live server serves contentMediaType:…
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