[Sonica-B]

Anyone who passes a number (or any other non-string) to Info.info() loses their whole /metrics endpoint: the call succeeds, and every later scrape of that registry fails with AttributeError: 'int' object has no attribute 'replace', so all metrics, not only the Info one, disappear. #1046 reports this with a float temperature; #521, #583 and #1011 hit the same failure earlier. The docs already say "val must be a dict[str, str] — both keys and values must be strings", but info() only rejects None (#1012).

This change makes info() raise ValueError for any key or value that is not a str, at the call that caused it, so the registry stays scrapeable. It does not coerce values to strings, following the comment on #1046 that enforcing strings lets users correct the mistake.

Refs #1046

flowchart LR
    subgraph Before
        A1["Info.info({'build_number': 42})"] --> B1["stored in Info._value"]
        B1 --> C1["generate_latest() / openmetrics generate_latest()"]
        C1 --> D1["AttributeError: whole scrape fails"]
    end
    subgraph After
        A2["Info.info({'build_number': 42})"] --> B2["ValueError at the call site"]
        B2 --> C2["previous value kept; scrape returns all metrics"]
    end

Loading

Before and after

from prometheus_client import CollectorRegistry, Gauge, Info, generate_latest

registry = CollectorRegistry()
Gauge('up_ok', 'An unrelated metric', registry=registry).set(1)
build = Info('build', 'Build information', registry=registry)
try:
    build.info({'version': '1.2.3', 'build_number': 42})
except ValueError as e:
    print('info() raised:', e)
try:
    print(generate_latest(registry).decode())
except Exception as e:
    print('scrape failed:', type(e).__name__, e.args[0])

Before (e2f2bf9):

scrape failed: AttributeError 'int' object has no attribute 'replace'

After:

info() raised: Info keys and values must be strings, got 'build_number': 42
# HELP up_ok An unrelated metric
# TYPE up_ok gauge
up_ok 1.0
# HELP build_info Build information
# TYPE build_info gauge
build_info 1.0

A non-string key ({1: 'x'}) failed the same way before (TypeError: object of type 'int' has no len() at scrape time) and is now rejected by the same check.

Changes

• prometheus_client/metrics.py: Info.info() checks that every key and value is a str before storing the dict. The existing None check and its message are unchanged.
• tests/test_core.py: TestInfo.test_non_string_keys_and_values covers an int, a float, a non-string key and a list, for an Info with and without labels, and checks that the previous value survives and that both the text and the OpenMetrics output still render. It fails on master and passes with the change.

Testing

Windows 11, Python 3.11.9:

• pytest tests -q: 440 passed, 14 skipped
• flake8 prometheus_client/ tests/: clean
• isort --check prometheus_client/ tests/: clean
• mypy prometheus_client/ tests/: the same 9 missing-optional-dependency errors as on master, none new