Fix InputLengthByte Calculation

[dev2-nomo]

Summary by CodeRabbit

• New Features

  • Added a utility to calculate the encoded size of variable-length integers, enabling more accurate size estimation and serialization workflows.

• Style

  • Reformatted transaction-related code for improved readability and consistency. No changes to behavior, interfaces, or error handling.

[coderabbitai]

Walkthrough

Formatting-only updates in raw_transaction.dart and a new int extension (varIntLength) added in var_uint.dart; no behavioral changes to existing transaction logic.

Changes

Cohort / File(s)	Summary
Transaction formatting updates lib/src/crypto/utxo/entities/raw_transaction/raw_transaction.dart	Reflowed long expressions and alignments in BTCRawTransaction.fromHex, RawTransaction.build, and EC8RawTransaction parsing/serialization. No logic, control flow, or API changes.
VarInt utility addition lib/src/utils/var_uint.dart	Added VarLengthUtil extension on int with getter varIntLength to compute varint encoded length (1/3/5/9 bytes based on value). Minor formatting in readVarSlice without behavior change.

Sequence Diagram(s)

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Suggested reviewers

• ThomasFercher

Poem

A bunny taps code with a gentle hop,
Lines realigned—no logic to swap.
A new varIntLength, tidy and neat,
Counting bytes with rhythmic beat.
With whiskers twitching, tests will pass—
Thump-thump! another polished class. 🐇✨

Pre-merge checks and finishing touches

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title Check	✅ Passed	The title succinctly captures the main intent of the changeset—correcting the calculation for input length bytes—without extraneous detail or vagueness, aligning with the PR’s key update.
Docstring Coverage	✅ Passed	No functions found in the changes. Docstring coverage check skipped.

✨ Finishing touches

🧪 Generate unit tests

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch fix_byte_length_calc

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📜 Recent review details

Configuration used: CodeRabbit UI

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between 4e15ff5 and a58f599.

📒 Files selected for processing (2)

• lib/src/crypto/utxo/entities/raw_transaction/raw_transaction.dart (9 hunks)
• lib/src/utils/var_uint.dart (2 hunks)

🔇 Additional comments (9)

lib/src/utils/var_uint.dart (2)

3-17: Good addition of the varIntLength getter extension.

The new VarLengthUtil extension correctly implements varint-encoded length calculations following the standard Bitcoin varInt specification. This provides a cleaner way to calculate the byte length of a varint without allocating memory.

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137-138: Formatting-only change looks good.

The multi-line split improves readability without changing functionality.

lib/src/crypto/utxo/entities/raw_transaction/raw_transaction.dart (7)

133-136: Formatting improvement for readability.

The condition is now properly split across multiple lines for better readability.

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239-240: Consistent formatting improvements in parsing logic.

Good formatting changes that improve readability by splitting long lines for variable assignments in the fromHex method.

Also applies to: 247-248, 259-260, 282-283

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307-308: Critical fix: Correct varint length calculation for inputs and outputs.

This is the key fix from the PR - using the new varIntLength extension method to correctly calculate the byte length of the varint that encodes the number of inputs/outputs. The previous implementation likely had incorrect calculations causing buffer size issues.

Also applies to: 314-315

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320-325: Formatting improvement for transaction byte length calculation.

Better readability with each component on its own line.

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496-497: EC8 transaction also benefits from the varint length fix.

The same critical fix applied to EC8RawTransaction, ensuring consistent and correct varint length calculations across both transaction types.

Also applies to: 503-504

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661-667: Formatting improvement in buffer length calculation.

Clean multi-line formatting for better readability.

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732-733: Consistent formatting in EC8 transaction parsing.

Good formatting consistency with the BTCRawTransaction parsing logic.

Also applies to: 744-745

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