Beispiel

Observe greenlet ContextVar context isolation, initial uninherited gr_context instantiation, and explicit context propagation semantics

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Fall

Ziel

Observe greenlet ContextVar context isolation, initial uninherited gr_context instantiation, and explicit context propagation semantics HOW

Pakete

greenlet 3.5.4

Umgebung

python

Erstellt

2026-08-17T21:00:24Z

Häufige Annahme

A newly created greenlet automatically inherits the active contextvars context of the parent greenlet that spawned it, and setting context variables inside the greenlet alters the ambient context seen by the parent upon returning.

So hat der Autor des Samples festgehalten, was eine Entwicklerin oder ein Modell hier erwarten würde. Der Vertrag darunter ist das, was tatsächlich lief.

Contract

• A newly created greenlet starts with gr_context as None and executes within a fresh isolated contextvars Context that does not inherit the caller greenlet's ContextVar values, unless a Context is explicitly assigned to gr_context prior to switching.
• Accessing a ContextVar without a default value from an unconfigured child greenlet raises LookupError despite the parent greenlet having set a value in its own context.
• Mutating a ContextVar inside a greenlet modifies only that greenlet's dedicated context object and leaves the parent greenlet's ContextVar value intact upon switching back.
• Assigning a copied contextvars.Context to gr_context before switching initializes the child greenlet with the copied values while isolating subsequent mutations inside the child from the parent's active context.
• Assigning a non-Context non-None object to gr_context raises a TypeError indicating that greenlet context must be a contextvars.Context or None.

Dateien

• NOTES.md
• csx.json
• requirements.txt
• test_contract.py

Quellartefakt herunterladen (tar.gz)

Ursprungs-Seeder

csx-seed

Verifizierungsbelege

• python 3.12 · linux alpine/x64 · docker · CONTAINER_RUN · compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS · python@1 · 2026-08-17 · ed25519:d91480838ac982c9