fix: Increase the limit of seeds from 4 to 8 for escrow accounts

[snawaz]

Issue

We encountered TooManySeeds (Custom Error: 14 or 0xe):

• https://solscan.io/tx/3rAZkwaH7PSpJTb1xjztbwusJpj5mGvGSBhgdQVo5ifs5eFaTH7Z9jhJanru54kwGLdL3XKi6TZDQYJEWR2c42ck

The older delegate had used Vec for seeds, but the new implementation uses fixed-size arrays to avoid heap allocation. These fixed-size arrays allowed upto 4 seeds. But the above failing instruction passes 5 seeds:

• ["token_escrow", followed by 3 seeds (32 bytes each), then an 8-byte zero seed]

Instruction data (after decoding):

[0, 0, 0, 0, 0, 0, 0, 0, 255, 255, 255, 255, 5, 0, 0, 0, 12, 0, 0, 0, 116, 111, 
107, 101, 110, 95, 101, 115, 99, 114, 111, 119, 32, 0, 0, 0, 224, 44, 225, 167, 
90, 132, 166, 170, 152, 1, 226, 3, 185, 117, 139, 9, 56, 129, 121, 8, 149, 189, 
81, 139, 183, 63, 79, 36, 246, 229, 194, 175, 32, 0, 0, 0, 241, 3, 142, 54, 165, 
6, 236, 130, 120, 166, 44, 190, 90, 71, 127, 231, 65, 218, 208, 252, 118, 31, 243, 
145, 160, 22, 98, 89, 109, 143, 80, 86, 32, 0, 0, 0, 198, 250, 122, 243, 190, 219,
173, 58, 61, 101, 243, 106, 171, 201, 116, 49, 177, 187, 228, 194, 210, 246, 224,
228, 124, 166, 2, 3, 69, 47, 93, 97, 8, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]

Fix

This PR increases the limit on the number of seeds from 4 to 8.

Cost Comparison

If we use Vec and ready to pay some extra CUs, then:

• Using fix-sized arrays, delegate consumes 18139 CU.
• Using Vec, delegate consumes 18268 CU.
• So the difference is 18268 - 18139 = 129 CU.

If we continue with fixed-size array approach, we can define a macro to reduce the verbosity in the code and can use it wherever we have such opportunity, something like:

let seeds_to_validate: &[&u8]] = as_slices!(args.seeds, limit: 8);

Summary by CodeRabbit

• New Features
  • Expanded seed validation to support 5–8 seeds in address-related flows. You can now provide up to eight seeds where applicable, enabling more flexible and complex configurations. Behavior for other counts is unchanged, and invalid counts still return an error. No action required; existing workflows continue to function as before.

[snawaz]

• fix: Increase the limit of seeds from 4 to 8 for escrow accounts #106 👈 (View in Graphite)
• main

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[coderabbitai]

\n\n## Walkthrough\nExpanded seed-count handling in src/processor/fast/delegate.rs: the seeds_to_validate match now supports 5–8 seeds by constructing matching seed arrays. Behavior for other counts and subsequent derived_pda computation/validation remains unchanged.\n\n## Changes\n| Cohort / File(s) | Summary of changes |\n| --- | --- |\n| Seed validation logic
src/processor/fast/delegate.rs | Extend seeds_to_validate match to support 5–8 seeds; construct corresponding seed arrays. Default TooManySeeds unchanged. No changes to derived_pda computation or later validation flow. |\n\n## Sequence Diagram(s)\nmermaid\nsequenceDiagram\n autonumber\n participant Caller\n participant Delegate as delegate.rs\n participant PDA as PDA Deriver\n participant Validator\n\n Caller->>Delegate: validate(seeds_to_validate)\n Note over Delegate: Match on seeds_to_validate length<br/>(1–4 existing, 5–8 newly handled)\n Delegate->>Delegate: Build seed array (1–8)\n Delegate->>PDA: derive_pda(seed array)\n PDA-->>Delegate: derived_pda\n Delegate->>Validator: validate_with_pda(derived_pda)\n Validator-->>Delegate: result\n Delegate-->>Caller: result\n alt >8 seeds\n Delegate-->>Caller: Error: TooManySeeds\n end\n\n\n## Estimated code review effort\n🎯 2 (Simple) | ⏱️ ~10 minutes\n\n

Pre-merge checks and finishing touches

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Description Check	⚠️ Warning	The provided description includes an “Issue” and “Fix” section but does not follow the repository’s required template which begins with a status/type table and uses headings like “Problem” and “Solution.” It also omits the top-level note and sections for “Before & After Screenshots,” “Other changes,” and “Deploy Notes.” While the narrative explains the root cause and fix clearly, it does not adhere to the structured template expected for consistency and complete context. Because the template ensures maintainers have all necessary information in a familiar format, the description needs updating to align with it.	Please revise the pull request description to include the required status/type table with PR status, type, core change flag, and issue link, rename “Issue” to “Problem” and “Fix” to “Solution,” and add the “Before & After Screenshots,” “Other changes,” and “Deploy Notes” sections or note if they are not applicable.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Title Check	✅ Passed	The title clearly and concisely describes the primary change by stating that the seed limit is increased from four to eight for escrow accounts, which directly matches the core update in the PR.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.

✨ Finishing touches

• 📝 Generate docstrings

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch snawaz/hotfix

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_{Comment @coderabbitai help to get the list of available commands and usage tips.}

[GabrielePicco]

LGTM!

We should support up to 16 seeds to cover all cases, but we can merge as it is to cover already most use-cases.

[snawaz]

LGTM!

We should support up to 16 seeds to cover all cases, but we can merge as it is to cover already most use-cases.

Yes. Created an issue: #108