Fix TailFile CRC file descriptor leak

[ArmentaRoberto]

What does this PR do?

Fixes a file descriptor leak in TailFile._open_file by closing the temporary file handle used to compute the CRC for rotation/truncation detection before opening the persistent tail handle.

Adds a regression test that tracks the CRC probe handle and verifies it is closed while the active tail handle remains open.

Motivation

TailFile._open_file opened one file handle to read the CRC prefix, then opened a second handle for tailing. The CRC handle was never closed, so every reopen path could leak a descriptor. On long-running Agents tailing files through rotations, truncations, or periodic reopens, this can eventually exhaust ulimit -n and cause unrelated I/O to fail with too many open files.

Validation:

• ddev -x test -fs datadog_checks_base
• ddev -x --no-interactive test datadog_checks_base -- -k tailfile
• ddev -x --no-interactive test datadog_checks_base reached 1475 passed, 40 skipped, then errored in Docker-backed Kerberos/SOCKS5 tests because local Docker is unavailable (docker points at a missing Colima socket and docker compose is not available in this environment).

Review checklist (to be filled by reviewers)

• Feature or bugfix MUST have appropriate tests (unit, integration, e2e)
• Add qa/required if this PR needs QA validation, or qa/skip-qa if it does not. Exactly one of the two is required.
• If you need to backport this PR to another branch, you can add the backport/<branch-name> label to the PR and it will automatically open a backport PR once this one is merged

[datadog-datadog-prod-us1-2]

   

✨ Fix all issues with BitsAI

⚠️ Warnings

🚦 18 Pipeline jobs failed

PR All Windows | test / j6712d43 / ddev on Windows     

🔧 Fix in code (Fix with Cursor).

AttributeError: module 'aiohttp.streams' has no attribute 'AsyncStreamReaderMixin'

PR All | test / jd316aba / ddev on Linux     

⬆️ Not caused by your changes. Rebase on a base branch once a fix is merged.

AttributeError: module 'aiohttp.streams' has no attribute 'AsyncStreamReaderMixin' in /home/runner/.local/share/hatch/env/virtual/ddev/SZM48zvK/ddev/lib/python3.13/site-packages/vcr/stubs/aiohttp_stubs.py:21

PR All | test / j06ca546 / SNMP     

🔄 Retry job. This looks flaky and may succeed on retry.

ConnectionError: HTTPSConnectionPool(host='ddintegrations.blob.core.windows.net', port=443): Max retries exceeded with url: /snmp/cisco-3850.snmprec (Caused by NameResolutionError)

View all 18 failed jobs.

🧪 20 Tests failed in 1 job

PR All | run  

test_bulk_table from test_check.py   (Fix with Cursor)

HTTPSConnectionPool(host='ddintegrations.blob.core.windows.net', port=443): Max retries exceeded with url: /snmp/cisco-3850.snmprec (Caused by NameResolutionError("HTTPSConnection(host='ddintegrations.blob.core.windows.net', port=443): Failed to resolve 'ddintegrations.blob.core.windows.net' ([Errno -2] Name or service not known)"))

test_cast_metrics from test_check.py   (Fix with Cursor)

HTTPSConnectionPool(host='ddintegrations.blob.core.windows.net', port=443): Max retries exceeded with url: /snmp/cisco-3850.snmprec (Caused by NameResolutionError("HTTPSConnection(host='ddintegrations.blob.core.windows.net', port=443): Failed to resolve 'ddintegrations.blob.core.windows.net' ([Errno -2] Name or service not known)"))

View all 20 test failures

ℹ️ Info

No other issues found (see more)

❄️ No new flaky tests detected

🎯 Code Coverage (details)
• Patch Coverage: 96.30%
• Overall Coverage: 88.29% (+0.33%)

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[dd-octo-sts]

Validation Report

All 21 validations passed.

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Validation	Description	Status
agent-reqs	Verify check versions match the Agent requirements file	✅
ci	Validate CI configuration and code coverage settings	✅
codeowners	Validate every integration has a CODEOWNERS entry	✅
config	Validate default configuration files against spec.yaml	✅
dep	Verify dependency pins are consistent and Agent-compatible	✅
http	Validate integrations use the HTTP wrapper correctly	✅
imports	Validate check imports do not use deprecated modules	✅
integration-style	Validate check code style conventions	✅
jmx-metrics	Validate JMX metrics definition files and config	✅
labeler	Validate PR labeler config matches integration directories	✅
legacy-signature	Validate no integration uses the legacy Agent check signature	✅
license-headers	Validate Python files have proper license headers	✅
licenses	Validate third-party license attribution list	✅
metadata	Validate metadata.csv metric definitions	✅
models	Validate configuration data models match spec.yaml	✅
openmetrics	Validate OpenMetrics integrations disable the metric limit	✅
package	Validate Python package metadata and naming	✅
qa-label	Validate the pull request declares whether it needs QA for the next Agent release	✅
readmes	Validate README files have required sections	✅
saved-views	Validate saved view JSON file structure and fields	✅
version	Validate version consistency between package and changelog	✅

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