fix: handle math.inf as max_retries without TypeError crash

[gn00295120]

Summary

max_retries=math.inf is recommended in the __init__ error message for unlimited retries, but causes a TypeError crash on the first API call.

Problem

# The error message explicitly recommends math.inf:
"max_retries cannot be None. If you want unlimited retries, pass `math.inf`..."

# But range() requires an integer:
for retries_taken in range(max_retries + 1):  # TypeError: 'float' object cannot be interpreted as an integer

Before fix:

import math
from anthropic import Anthropic

client = Anthropic(max_retries=math.inf)
client.messages.create(...)
# TypeError: 'float' object cannot be interpreted as an integer

After fix:

client = Anthropic(max_retries=math.inf)
client.messages.create(...)  # works — retries up to sys.maxsize times

Changes

• Cap range() limit at sys.maxsize when max_retries exceeds it (handles math.inf and very large floats)
• Fix applied to both sync (_retry_request) and async (_retry_request) paths
• Update max_retries type annotation to int | float on BaseClient

Test plan

• math.inf: range() no longer raises TypeError
• max_retries=2: range_limit = 3 (unchanged behavior)
• max_retries=0: range_limit = 1 (unchanged behavior)
• 151 existing client tests pass, 0 failures

[Copilot]

Pull request overview

Fixes a runtime crash when users follow the client’s own guidance to set max_retries=math.inf for “unlimited retries”, by preventing range() from receiving an infinite value in the request retry loop(s).

Changes:

• Broaden BaseClient.max_retries annotation to int | float.
• Add a capped range_limit for the sync request retry loop to avoid TypeError when max_retries is math.inf.
• Apply the same retry-loop change to the async request path.

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[Copilot]

range_limit can still become a float when max_retries is a finite float < sys.maxsize (e.g. 2.0 or 3.5), which will still raise TypeError in range(range_limit). Since __init__ currently advertises passing “a very high number” and this PR expands the type to int | float, consider normalizing here (or earlier) to an int (e.g. accept only integer-valued floats via .is_integer(), handle math.inf explicitly, and reject nan/non-integral values with a clear error).

[gn00295120]

Fixed — now explicitly checks for math.inf and >= sys.maxsize, then uses int(max_retries) + 1 for finite values. Applied to both sync and async loops.

[Copilot]

Capping range_limit to sys.maxsize changes the semantics for max_retries >= sys.maxsize: the loop will run sys.maxsize times, which corresponds to sys.maxsize - 1 retries (since the first iteration is the initial attempt). If the intent is “retries up to sys.maxsize times” (per PR description), the cap likely needs to be applied to max_retries and then use effective_max_retries + 1 for the range (i.e. allow sys.maxsize + 1 iterations when max_retries is infinite/very large).

[gn00295120]

Practically irrelevant — whether it's sys.maxsize or sys.maxsize - 1 retries, both are effectively infinite. Adding + 1 could actually overflow.

[Copilot]

The async retry loop uses the same range_limit computation, so it has the same failure mode when max_retries is a finite float (< sys.maxsize) and the same off-by-one semantics when capping at sys.maxsize. Consider sharing a small helper to compute an int iteration limit to keep sync/async behavior identical and avoid drifting fixes.

[gn00295120]

Fixed — both sync and async loops now use the same corrected logic.

[Copilot]

Changing the attribute annotation to max_retries: int | float helps communicate support for math.inf, but the constructor parameter is still annotated as int and FinalRequestOptions.get_max_retries() is typed to take/return int (see src/anthropic/_models.py). This inconsistency will surface for type-checkers and makes it unclear which layer is responsible for validating/coercing floats; consider updating the public __init__ signature and/or ensuring get_max_retries() continues to return an int by normalizing self.max_retries at assignment time.

[gn00295120]

Fixed — updated __init__ parameter types in BaseClient, SyncAPIClient, and AsyncAPIClient to int | float. Also updated FinalRequestOptions.get_max_retries() return type.