Implement updateFile JSON-RPC method

[aceppaluni]

Problem

The TCK server does not implement updateFile, so the TCK driver's FileUpdateTransaction suite cannot run against the Python SDK. The SDK transaction (src/hiero_sdk_python/file/file_update_transaction.py) already exists with all needed setters: set_file_id, set_keys, set_expiration_time, set_contents, set_file_memo.

Blocked by hiero-ledger#2488 (createFile) — this handler goes in the file-service TCK modules hiero-ledger#2488 creates, and the driver needs a created file to update. Use hiero-ledger#2489 (getFileContents) / hiero-ledger#2490 (getFileInfo) to verify update results end-to-end.

Solution

Add an updateFile handler wrapping FileUpdateTransaction. Structurally identical to the createFile handler from hiero-ledger#2488, plus fileId, returning status only.

Method contract (from the spec): all inputs optional.

Input	Type	Notes
fileId	string	File to update
keys	string[]	DER-encoded hex; threshold keys not allowed for update (unlike create)
contents	string	New contents; empty string means "leave unchanged"
expirationTime	string	Seconds since epoch; must be strictly later than current
memo	string	UTF-8, max 100 bytes
commonTransactionParams	object

Output: status — reuse StatusOnlyResponse from tck/response/base.py; no new response class needed.

Implementation steps:

1. Add UpdateFileParams(BaseTransactionParams) to tck/param/file.py — mirror CreateFileParams plus fileId.
2. Add the handler to tck/handlers/file.py: parse fileId via FileId.from_string(), map the rest as in createFile, execute, return StatusOnlyResponse(ResponseCode(receipt.status).name).
3. Add a unit test under tests/tck/.

Details that matter:

• contents="" must NOT clear the file. Per the spec, empty string means content unchanged — so parse with non_empty_string_or_none() (tck/util/param_utils.py) so "" becomes None and set_contents is never called with it. Add a comment explaining this, since it looks like a bug otherwise.
• expirationTime validation is server-side — the network rejects non-increasing values; don't validate client-side, let the error propagate.
• Threshold keys are disallowed by the spec for update but get_key_from_string() won't reject them — the network will. Acceptable; note it in the PR.
• Only call setters for non-None params: the spec distinguishes omitted fields (unchanged) from set fields.

Acceptance criteria

• updateFile registered and dispatchable
• contents="" leaves file content unchanged (verified via getFileContents)
• All inputs mapped; omitted params leave fields untouched
• Invalid fileId format → SDK internal error; non-existent ID → network INVALID_FILE_ID
• Unit test added; uv run pytest tests/tck -q passes

Spec: https://github.com/hiero-ledger/hiero-sdk-tck/blob/main/docs/test-specifications/file-service/FileUpdateTransaction.md

JS reference: https://github.com/hiero-ledger/hiero-sdk-js/blob/main/tck/methods/file.ts (updateFile)

[aceppaluni]

@learnmore Can you explain what this issue is asking me to do?

[codecoach-learning]

What This Issue Is Asking You To Do

This issue asks you to add an updateFile JSON-RPC method to the TCK (Test Compatibility Kit) server so that the Python SDK can be tested against the standard Hiero TCK test suite.

The Big Picture

The TCK is a test framework that verifies SDK implementations behave correctly. It works by sending JSON-RPC commands to a "TCK server" (which wraps the SDK), and the server translates those commands into actual SDK calls. Right now, the Python TCK server doesn't support updateFile, so those tests can't run.

What You Need to Build

1. A params class in tck/param/file.py

Add UpdateFileParams — similar to CreateFileParams (which hiero-ledger#2488 adds) but with an extra fileId field. This class defines what inputs the method accepts.

2. A handler function in tck/handlers/file.py

This is the core work. The handler should:

• Parse the incoming fileId string using FileId.from_string()
• Create a FileUpdateTransaction, calling setters only for non-None params (omitted fields should leave the file unchanged)
• Execute the transaction and return a StatusOnlyResponse with the receipt status

3. A unit test under tests/tck/

Verify the handler behaves correctly.

One Tricky Detail

The spec says contents="" (empty string) means "leave the content unchanged" — it does NOT mean "clear the file". To handle this, use the existing non_empty_string_or_none() utility from tck/util/param_utils.py, which converts "" to None. Then since you only call set_contents for non-None values, an empty string will correctly result in no change. Add a comment here — without it, this looks like a bug.

What You Don't Need to Build

• The SDK transaction itself (src/hiero_sdk_python/file/file_update_transaction.py) already exists with all the needed setters
• No new response class — reuse StatusOnlyResponse from tck/response/base.py
• No client-side validation of expirationTime — let the network reject bad values

References

• JS reference implementation: hiero-sdk-js updateFile
• Spec: FileUpdateTransaction.md

⚠️ Note: This is blocked by hiero-ledger#2488 (createFile), since you need a file to exist before you can update it.

[aceppaluni]

@learnmore Can you explain what this issue is asking for?

[aceppaluni]

@learnmore Can you explain what this issue is asking for?

[aceppaluni]

@learnmore Can you explain what this issue is asking for?

[aceppaluni]

@learnmore can you help me understand this?

[aceppaluni]

@codecoach-learning Can you help me understand this?

[aceppaluni]

@learnmore hello

[aceppaluni]

@learnmore test

[aceppaluni]

@learnmore hello

[codecoach-learning]

Hi! Happy to help. It looks like you've asked a few times, so let me give you a clear, simple explanation.

What This Issue Is Asking You To Do

The goal is to add an updateFile command to the TCK server — a small test-helper server that wraps the Python SDK.

Why it matters

The Hiero TCK (Test Compatibility Kit) sends JSON-RPC commands to test that the SDK works correctly. The Python SDK already has FileUpdateTransaction built, but the TCK server doesn't know how to handle an updateFile request yet. This issue asks you to wire them together.

The 3 things you need to add

1. tck/param/file.py — define the inputs
Add an UpdateFileParams class that lists what fields updateFile accepts:

• fileId (which file to update)
• keys, contents, expirationTime, memo
• commonTransactionParams

2. tck/handlers/file.py — the actual handler
This function receives those params and:

• Parses fileId with FileId.from_string()
• Creates a FileUpdateTransaction and calls setters only if the param was provided (omitted = leave unchanged)
• Returns a StatusOnlyResponse with the result

3. tests/tck/ — a unit test
Verify it works.

The one gotcha to watch out for

contents="" (empty string) should mean "don't change the contents", NOT "clear the file." Use the existing non_empty_string_or_none() utility from tck/util/param_utils.py so empty string becomes None, and then skip calling set_contents when it's None. Add a comment explaining this — it looks like a bug without one.

What you don't need to do

• The SDK transaction itself already exists in src/hiero_sdk_python/file/file_update_transaction.py
• No new response class needed — reuse StatusOnlyResponse from tck/response/base.py

Does that help clarify things? Feel free to ask about any specific part!