[TINGyu123644]

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Link to Issue or Description of Change

1. Link to an existing issue (if applicable):

• Closes: FileArtifactService changes CRLF and CR line endings in text artifacts #7914

2. Or, if no issue exists, describe the change:

Problem:
FileArtifactService changes the line endings of text artifacts. A text artifact containing \r\n or a lone \r loads back with \n in their place: the payload is read with Path.read_text, whose universal-newline mode rewrites both, and written with Path.write_text, which translates \n to os.linesep (so on Windows every \n is stored as \r\n). InMemoryArtifactService and GcsArtifactService return the saved text unchanged, so the same artifact differs only on the file backend - which is what adk web and adk run use by default (use_local_storage=True, via create_local_artifact_service). CSV files (RFC 4180 uses CRLF), patches, and Windows-authored text a tool saves therefore load back different from what was saved.

Solution:
Read the payload with read_bytes().decode("utf-8") and write it with write_bytes(text.encode("utf-8")) so the round trip is byte-exact on every platform, matching the in-memory and GCS backends. The staging write already used write_bytes for inline_data; this makes the text path consistent with it. The metadata document is JSON and is unaffected by newline translation, so its reader is left as is.

Testing Plan

Unit Tests:

• I have added or updated unit tests for my change.
• All unit tests pass locally.

Added test_save_load_preserves_crlf_and_cr_line_endings, parametrized over IN_MEMORY, GCS, and FILE, asserting "id,name\r\n1,a\r\n2,b\rc\n" round-trips unchanged. Local results:

# before the fix (new test only)
1 failed, 2 passed
FAILED test_save_load_preserves_crlf_and_cr_line_endings[ArtifactServiceType.FILE]

# after the fix
tests/unittests/artifacts/  ->  985 passed
tests/unittests/cli/utils/test_local_storage.py  ->  passed
tests/unittests/cli/utils/test_service_factory.py  ->  passed
  (3 pre-existing failures from a missing optional `a2a` module in this
   environment, unrelated to the change)

ruff check (repo config) and pyink --check are clean for both touched files.

Manual End-to-End (E2E) Tests:

The issue's reproducer, run against main and against this branch:

import asyncio, tempfile
from google.genai import types
from google.adk.artifacts.file_artifact_service import FileArtifactService
from google.adk.artifacts.in_memory_artifact_service import InMemoryArtifactService

async def main():
  text = "id,name\r\n1,a\r\n2,b\rc\n"
  for svc in (FileArtifactService(root_dir=tempfile.mkdtemp()), InMemoryArtifactService()):
    await svc.save_artifact(app_name="a", user_id="u", session_id="s",
                            filename="t.csv", artifact=types.Part(text=text))
    got = await svc.load_artifact(app_name="a", user_id="u", session_id="s",
                                  filename="t.csv")
    print(type(svc).__name__, repr(got.text), got.text == text)

asyncio.run(main())

Before: FileArtifactService 'id,name\n1,a\n2,b\nc\n' False / InMemoryArtifactService ... True
After: both print True.

Checklist

• I have read the CONTRIBUTING.md document.
• I have performed a self-review of my own code.
• I have commented my code, particularly in hard-to-understand areas.
• I have added tests that prove my fix is effective or that my feature works.
• New and existing unit tests pass locally with my changes.
• I have manually tested my changes end-to-end.
• Any dependent changes have been merged and published in downstream modules.

Additional context

The change was drafted with an AI coding assistant and reviewed before submission.

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[GWeale]

thanks for sending this over, @TINGyu123644. #7915 makes the same change to FileArtifactService to read and write text artifacts as raw utf-8 bytes, and since that one is already approved in review, we're going ahead with it and closing this one. please open a new issue if you still see this once it lands.