Fix how the string argument is treated (Fixed Bytes instead of string)

[scx1332]

This pull request was initialized by file-diff-engine for a claude-backed agent task.

Branch: fd-agent/cli-string-parse-fixedbytes-return
Base branch: main
Task runner: claude
Model: opus
Pull request completion mode: AutoReady
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Task:
fix

fn parse_cli_string_value(value: &str) -> Result<FixedBytes<128>>

this function should return this FixedBytes argument instead of string to match our attribute value type

[scx1332]

Plan

Fix parse_cli_string_value to return Result<FixedBytes<128>> instead of Result<String> so its output matches the on-chain attribute value type (bytes32[4] / FixedBytes<128>).

Changes (all in crates/arkiv-cli/src/main.rs)

1. Import FixedBytes from alloy_primitives.
2. Add pack_string_attr_value(&[u8]) -> Result<FixedBytes<128>> helper: validates that the byte slice is at most 128 bytes and packs it left-aligned, zero-padded into a FixedBytes<128>. Reused by both CLI and JSON code paths.
3. Change parse_cli_string_value(value: &str) -> Result<FixedBytes<128>> so it parses quotes/escapes as before but produces a FixedBytes<128> via the helper. The 128-byte ceiling is now enforced at parse time.
4. Change BatchAttributeValue::String { string: FixedBytes<128> } and add a custom deserialize_with that takes a JSON string and packs it via the same helper, preserving the existing JSON batch shape ({"name": "title", "string": "the answer"}).
5. Update build_attribute so the String arm passes string.as_slice() (already 128-byte packed) into Attribute::string(name, ...). The constructor's chunk-of-32 logic happily handles a pre-packed 128-byte slice and produces the same on-chain bytes32[4].

Verification

• cargo build -p arkiv-cli
• cargo test -p arkiv-cli if any tests are present
• Manually re-check the CLI parse path: unquoted, single-/double-quoted, escapes, oversized (>128 bytes) string — last one should now error during parse.

No other crates reference parse_cli_string_value or BatchAttributeValue::String.

[scx1332]

Summary report

Fix landed in commit c2a47a6.

What changed

All edits in crates/arkiv-cli/src/main.rs:

1. Imported FixedBytes from alloy_primitives.
2. Added pack_string_attr_value(bytes: &[u8]) -> Result<FixedBytes<128>> — a shared helper that rejects inputs over 128 bytes and packs the rest into a left-aligned, zero-padded FixedBytes<128>. This mirrors the on-chain Attribute { valueType: ATTR_STRING, value: bytes32[4] } layout that arkiv_bindings::Attribute::string produces internally.
3. Changed parse_cli_string_value(value: &str) -> Result<FixedBytes<128>> (was Result<String>). The quote/escape parsing logic is preserved verbatim; only the final return goes through the new helper, so the 128-byte limit is now enforced at parse time instead of inside Attribute::string.
4. Changed the BatchAttributeValue::String variant's string field from String to FixedBytes<128> and added a #[serde(deserialize_with = "de_string_attr_value")] adapter so JSON batch files keep their existing shape ({"name": "title", "string": "the answer"}) — the adapter feeds the JSON string through the same pack_string_attr_value helper.
5. Updated build_attribute so the String arm passes string.as_slice() (now 128 packed bytes) into Attribute::string(name, ...). The constructor's chunks(32) loop produces the same on-chain bytes32[4] either way, so wire-format output is unchanged.

Verification

• cargo build -p arkiv-cli — passes.
• cargo clippy -p arkiv-cli -- -D warnings — clean.
• cargo test -p arkiv-cli — runs (crate has no unit tests today; nothing regressed).

Notes

• JSON batch consumers (e.g. scripts/fixtures/attributes-all-types.json) keep working without changes; only the in-memory representation of the parsed value changed.
• The user-visible error for an oversized string now surfaces during CLI/JSON parsing (attribute string value exceeds 128 bytes (N bytes)) rather than later inside Attribute::string.
• No other crates reference parse_cli_string_value or BatchAttributeValue::String.