Rendered from docs/obligations/0159-a-sentence-that-opens-with-a-hash-and-an-issue-number-is-folded-into-the-sentence-before-it.md in the Headwater corpus. Every document on this half of the site is typed by the taxonomy the descriptor names: corpus.json.

A sentence that opens with a hash and an issue number is folded into the sentence before it

Context

opens_a_sentence in engine/crates/doc/src/sentences.rs decides whether a terminator ends a sentence. It admits a capital, a digit, and one of ", “, (, [, a backtick, *, _ and §. It does not admit #. The guard exists to stop an abbreviation from splitting one sentence into two, which Q5 measured as the largest source of false findings.

A hash followed by a number is how this corpus cites an issue in running prose, and the citation often opens a sentence. When it does, the terminator before it ends nothing. Both sentences reach language.controlled.not_met as one, and the reported word count is their sum.

Measured, in a scratch paragraph appended to docs/spec/06-engine-architecture.md and then removed. Two sentences of 15 and 16 words, where the second opens with #346, are reported as one sentence of 31 words at column 1. The same pair with the second sentence opening with a word is reported as two sentences and no finding. A code span at the head of a sentence splits correctly, because a backtick is in the set.

Obligation

The finding is wrong and its remediation is impossible. The rule reports a sentence that is already two sentences, and the fix line says to split a sentence that is already split. An author who follows the fix line rewrites text that met the limit before the edit.

The character set is a literal in one function, and no declaration stands behind it. Nothing states which openers a language regime admits. So an adopting corpus whose house style opens a sentence with an omitted character meets the same fold, with no way to see why. A hash is the case this repository can measure, because this repository cites issues that way. It is not the only character the literal omits.

This is a defect in a shipped rule rather than a gap in a fixture set. HW-OBL-0153 records that the splitter has no data-driven corpus, and a corpus that held this case would have caught it.

Discharge

Admit # in opens_a_sentence, with the same reasoning the digit already carries, and add the pair above to the splitter's cases. Then read the corpus for a sentence whose reported length falls once the fold is gone. A finding that this defect created is a sentence somebody may already have rewritten.

Decide at the same time whether the opener set stays a literal or becomes something a regime declares. The second is the wider fix and it is the one an adopting corpus needs. The first is enough for the character this repository writes.

This record is discharged. opens_as_a_name in engine/crates/doc/src/sentences.rs admits a hash that a digit follows, and a test in that file holds the pair. Commit 0ee88a2d made the change and read the corpus again, and 301 findings became 299. The opener set stays a literal, and the comment on that function records the choice. The owner accepted the discharge on 2026-09-30, in the roadmap review of that day.