fix(contested-names): normalize DPNS label in vote poll construction + pre-flight existence check

[lklimek]

User story

Imagine you are a masternode operator using Dash Evo Tool. A new DPNS username contest opens — say alice — and you cast your Lock vote. Today, if the contested name contains any of i, l, or o (the overwhelming majority of real names), the app sits silently for about 70 seconds and then flashes an "An unexpected error occurred" banner with no actionable hint. Your vote never lands on Platform.

After this fix, the vote either succeeds on the first attempt or fails in well under a second with a clear, actionable message: "The contested name … is not currently open for voting. It may have been resolved or may not exist. Refresh the contested names list and try again."

Summary

• Normalize the DPNS label via convert_to_homograph_safe_chars (maps i→1, l→1, o→0, then lowercase) before building the vote poll's index_values. Platform stores contested polls under the normalized label; the old code used the raw label, so any name containing i/l/o silently mismatched the index.
• Add a pre-flight existence check via ContestedResource::fetch_many before broadcasting any signed vote state transition. Short-circuits the DAPI retry chain (client-side timeout: 10s × retries: 6 × ~7 evonode attempts) that otherwise burns ~70 s on a poll that isn't there.
• New typed error variant TaskError::VotePollNotFound { name } carrying an Everyday-User-persona message ("what happened + what to do"). Replaces the opaque timeout path.
• Extract the index-values construction as a pure helper (dpns_vote_poll_index_values) with unit-test coverage pinning the normalization contract (alice → a11ce, bar22 → bar22).

Why

Drive-abci server logs from three separate PR 827 TC-090 runs (heights 318950, 319048, 319073) showed VotePollNotFoundError at PrepareProposal. The tx passed CheckTx because validates_full_state_on_check_tx() for MasternodeVote was only added to Platform in December 2025 (b44ccff5, v3.1.0-dev.1 onward). Testnet v3.0.x clients must therefore detect the missing poll themselves or pay the full retry timeout.

In the DET GUI, VoteOnDPNSNames happens to pass contested_name.normalized_contested_name — so the GUI worked. CLI, MCP, scheduled replay, and E2E tests passed raw labels, so they hit the bug. The fix is at the backend boundary so every caller is covered regardless of whether they pre-normalized.

Scope

• src/backend_task/contested_names/vote_on_dpns_name.rs — normalization + pre-flight check + helper + unit tests.
• src/backend_task/error.rs — VotePollNotFound { name } variant.

Other ContestedDocumentResourceVotePoll construction sites were surveyed and left unchanged:

• query_dpns_vote_contenders.rs — only called with labels fetched from Platform's index (already normalized).
• query_ending_times.rs — only reads index_values from polls returned by Platform.

Relationship to PR #827

This fix was discovered during backend E2E test work on #827 (TC-090 masternode vote verification) and is being filed here as a standalone PR against v1.0-dev because the bug is orthogonal to the test-only scope of #827. #827 currently carries the same commit on its branch; on rebase after this merges, git will deduplicate it.

Test plan

• cargo check --all-features --tests — clean
• cargo clippy --all-features --all-targets -- -D warnings — clean (verified on source branch prior to cherry-pick)
• cargo +nightly fmt --all — no changes
• cargo test --all-features --workspace --lib --bins — 455 passed, 0 failed (includes two new unit tests: index_values_normalizes_homograph_chars, index_values_preserve_non_homograph_label)
• TC-090 end-to-end against testnet with e0emnduubiwud (contains i) — PASS in 30.11 s, vote broadcast returned proof in 2.4 s, pre-flight confirmed the poll, VotePollNotFound never raised. (Previously: 3 consecutive failures at ~70 s each.)

_{🤖 Co-authored by Claudius the Magnificent AI Agent}

Summary by CodeRabbit

Release Notes

• Bug Fixes
  • DPNS voting now validates that an active vote poll exists before processing vote submissions.
  • Improved consistency in DPNS name normalization during voting operations.
  • Added clear error messaging when attempting to vote on a DPNS name with no active vote poll, instructing users to refresh the list and retry.

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro

Run ID: 6d1d6ddd-e902-43a6-acec-69e153e6355a

📥 Commits

Reviewing files that changed from the base of the PR and between 801cf07 and 1f50522.

📒 Files selected for processing (1)

• src/backend_task/contested_names/vote_on_dpns_name.rs

📝 Walkthrough

Walkthrough

The DPNS voting process now applies homograph normalization to names before indexing and includes a pre-flight Platform query to verify an open vote poll exists before submitting votes. A new error variant communicates when the poll is not available.

Changes

Cohort / File(s)	Summary
DPNS Vote Validation & Normalization src/backend_task/contested_names/vote_on_dpns_name.rs	Added homograph-safe character normalization for DPNS names via convert_to_homograph_safe_chars. Implemented pre-flight VotePollsByDocumentTypeQuery to verify open vote poll exists before submission. Introduced helper dpns_vote_poll_index_values to standardize index values as ["dash", normalized_label]. Added unit tests for normalization behavior.
Error Handling src/backend_task/error.rs	Added TaskError::VotePollNotFound { name: String } variant with user-facing error message directing users to refresh the contested names list and retry.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~22 minutes

Poem

🐰 A hop through the contested names so fine,
We normalize and verify, all in line,
Before each vote we cast with care,
Homographs balanced, fair and square!
The poll exists—now vote with cheer, ✨

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title directly and specifically describes the main changes: DPNS label normalization in vote poll construction and the addition of a pre-flight existence check, which are the core fixes implemented in this PR.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/contested-names-normalize-dpns-vote-poll

Warning

Review ran into problems

🔥 Problems

Timed out fetching pipeline failures after 30000ms

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[Copilot]

Pull request overview

Fixes DPNS contested-name voting failures by ensuring vote polls are addressed using Platform’s homograph-safe normalized label, and by adding a fast pre-flight existence check to avoid long retry/timeout paths when the poll doesn’t exist.

Changes:

• Normalize DPNS label via convert_to_homograph_safe_chars when building vote poll index_values.
• Add a pre-flight ContestedResource::fetch_many existence check to fail fast with a typed error instead of timing out.
• Introduce TaskError::VotePollNotFound { name } and add unit tests pinning the index-values normalization behavior.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
src/backend_task/error.rs	Adds a typed VotePollNotFound error variant with an actionable user-facing message.
src/backend_task/contested_names/vote_on_dpns_name.rs	Normalizes vote poll index values, adds pre-flight poll existence check, and introduces unit tests for normalization.

---

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[thepastaclaw]

⏳ Review in progress (commit 1f50522)

[coderabbitai]

🧹 Nitpick comments (1)

src/backend_task/contested_names/vote_on_dpns_name.rs (1)

34-67: Optional: avoid normalizing the same label twice.

convert_to_homograph_safe_chars(name) is invoked on line 66 to build normalized_label, and again inside dpns_vote_poll_index_values(name) on line 67. Cheap, but makes it easy for future edits to the two call sites to drift apart. Consider accepting the already-normalized label in the helper:

♻️ Proposed refactor

-/// Returns `[Value::from("dash"), Value::Text(normalized_label)]`.
-fn dpns_vote_poll_index_values(name: &str) -> Vec<Value> {
-    vec![
-        Value::from("dash"),
-        Value::Text(convert_to_homograph_safe_chars(name)),
-    ]
-}
+/// Returns `[Value::from("dash"), Value::Text(normalized_label.to_owned())]`.
+///
+/// Caller is responsible for normalizing the label via
+/// `convert_to_homograph_safe_chars` before invoking this helper.
+fn dpns_vote_poll_index_values(normalized_label: &str) -> Vec<Value> {
+    vec![
+        Value::from("dash"),
+        Value::Text(normalized_label.to_owned()),
+    ]
+}

-        let normalized_label = convert_to_homograph_safe_chars(name);
-        let index_values = dpns_vote_poll_index_values(name);
+        let normalized_label = convert_to_homograph_safe_chars(name);
+        let index_values = dpns_vote_poll_index_values(&normalized_label);

Update the index_values_* tests to pass normalized inputs, and add one test that asserts convert_to_homograph_safe_chars("alice") == "a11ce" to keep the normalization coverage.

🤖 Prompt for AI Agents

Verify each finding against the current code and only fix it if needed.

In `@src/backend_task/contested_names/vote_on_dpns_name.rs` around lines 34 - 67,
The helper dpns_vote_poll_index_values currently takes raw name and calls
convert_to_homograph_safe_chars again, causing double normalization; change
dpns_vote_poll_index_values to accept a pre-normalized label (e.g., fn
dpns_vote_poll_index_values(normalized_label: &str) -> Vec<Value>), update the
call site in AppContext::vote_on_dpns_name to pass normalized_label instead of
name, and update the index_values_* tests to pass normalized inputs; also add a
small unit test asserting convert_to_homograph_safe_chars("alice") == "a11ce" to
retain normalization coverage.

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Nitpick comments:
In `@src/backend_task/contested_names/vote_on_dpns_name.rs`:
- Around line 34-67: The helper dpns_vote_poll_index_values currently takes raw
name and calls convert_to_homograph_safe_chars again, causing double
normalization; change dpns_vote_poll_index_values to accept a pre-normalized
label (e.g., fn dpns_vote_poll_index_values(normalized_label: &str) ->
Vec<Value>), update the call site in AppContext::vote_on_dpns_name to pass
normalized_label instead of name, and update the index_values_* tests to pass
normalized inputs; also add a small unit test asserting
convert_to_homograph_safe_chars("alice") == "a11ce" to retain normalization
coverage.

---

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Configuration used: Path: .coderabbit.yaml

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📥 Commits

Reviewing files that changed from the base of the PR and between eb7c162 and 801cf07.

📒 Files selected for processing (2)

• src/backend_task/contested_names/vote_on_dpns_name.rs
• src/backend_task/error.rs