fix: correct TypeTag error message and harden vector parsing

[beer-1]

Summary

• Fix typo: "known TypeTag" → "unknown TypeTag" in StringifyTypeTag error fallback
• Fix TypeTagFromString vector parsing to correctly handle nested types and reject non-vector prefixes

Bug details

Bug 1: StringifyTypeTag returned errors.New("known TypeTag") for unrecognized variants — clearly should be "unknown".

Bug 2: TypeTagFromString used strings.HasPrefix(str, "vector") which would match any string starting with "vector" (e.g., a hypothetical struct vectorFoo). Changed to require both vector< prefix and > suffix, then extract inner type via str[7:len(str)-1].

This correctly handles nested vectors:

• vector<u8> → inner: u8
• vector<vector<u8>> → inner: vector<u8> → recursion works

Test plan

• Added TestStringifyTypeTag_UnknownError — verifies corrected error message
• Added TestTypeTagFromString_NestedVector — tests depth 1, 2, and 3 nested vectors

🤖 Generated with Claude Code

Summary by CodeRabbit

• Bug Fixes

  • Corrected the reported error message for unknown type-tag operations.
  • Strengthened validation for vector-type strings to require proper angle-bracket syntax.

• Tests

  • Added tests covering type-tag error messages, nested vector parsing, and a negative regression for malformed vector strings.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: ec49c831-209f-421a-8b3f-29fb44e9f14c

📥 Commits

Reviewing files that changed from the base of the PR and between 1cae7f7 and bf15bcd.

📒 Files selected for processing (1)

• api/exposed_test.go

🚧 Files skipped from review as they are similar to previous changes (1)

• api/exposed_test.go

---

Walkthrough

Updated vector type parsing to require exact vector<...> form and use direct slicing; corrected a fallback error message from "known TypeTag" to "unknown TypeTag". Added tests verifying the new error message and nested vector parsing (including a negative case).

Changes

Cohort / File(s)	Summary
Error Message & Vector Parsing Improvements api/exposed.go	Changed fallback error text in StringifyTypeTag to "unknown TypeTag". Tightened TypeTagFromString to require vector< prefix and > suffix and replaced trim-based substring extraction with direct slicing (str[7:len(str)-1]).
Test Coverage Expansion api/exposed_test.go	Added TestStringifyTypeTag_UnknownError to assert the exact error message and TestTypeTagFromString_NestedVector to validate parsing of nested vector<...> forms and reject vectorFoo.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Poem

🐰 I munched a bug, found "known" was wrong,
Sliced vectors neat where they belong,
Tests hop in, three layers deep,
Now parsing wakes from sloppy sleep,
🥕✨

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 33.33% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The pull request title accurately summarizes the main changes: fixing the TypeTag error message typo and hardening vector parsing validation.

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✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/typetag-bugs

---

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[coderabbitai]

🧹 Nitpick comments (1)

api/exposed_test.go (1)

92-119: Add a direct regression case for non-vector<...> prefixes.

Given the original bug, it’s worth explicitly asserting that inputs like vectorFoo are not treated as vectors.

✅ Suggested test extension

 func TestTypeTagFromString_NestedVector(t *testing.T) {
@@
 	inner3 := inner2.Value.(*types.TypeTag__Vector)
 	require.IsType(t, &types.TypeTag__U8{}, inner3.Value)
+
+	// regression: should not match arbitrary "vector" prefix
+	_, err = TypeTagFromString("vectorFoo")
+	require.Error(t, err)
 }

🤖 Prompt for AI Agents

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

In `@api/exposed_test.go` around lines 92 - 119, Extend
TestTypeTagFromString_NestedVector to add a regression assertion that inputs not
using the proper "vector<...>" syntax (e.g. "vectorFoo") are not parsed as a
vector: call TypeTagFromString("vectorFoo") inside
TestTypeTagFromString_NestedVector and assert it returns an error
(require.Error) or at minimum that the returned tag is not a
*types.TypeTag__Vector (require.NotIsType), so the parser doesn't treat
"vectorFoo" as a vector type.

🤖 Prompt for all review comments with AI agents

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

Nitpick comments:
In `@api/exposed_test.go`:
- Around line 92-119: Extend TestTypeTagFromString_NestedVector to add a
regression assertion that inputs not using the proper "vector<...>" syntax (e.g.
"vectorFoo") are not parsed as a vector: call TypeTagFromString("vectorFoo")
inside TestTypeTagFromString_NestedVector and assert it returns an error
(require.Error) or at minimum that the returned tag is not a
*types.TypeTag__Vector (require.NotIsType), so the parser doesn't treat
"vectorFoo" as a vector type.

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: 868f69b0-f3f5-4ced-b32d-fed68cc3b1e0

📥 Commits

Reviewing files that changed from the base of the PR and between c39ce30 and 1cae7f7.

📒 Files selected for processing (2)

• api/exposed.go
• api/exposed_test.go

[traviolus]

LGTM