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an offline map explorer where each world, from a game map to a city's open data, ships as one .atlas file

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atlas / docs / decisions / 0014-the-depcheck-pragma.md
0014-the-depcheck-pragma.md 2.1K source

14. A boundary crossing is annotated in place, with a reason

  • Date: 2026-08-02
  • Status: accepted
  • Where it is written down: issue #5 §9, §10 decision 13; tools/depcheck/report.go

Context

The project's architectural contracts are encoded as static analysis: the lane import matrix, the stdlib-only rule for format/, hostenv purity, network confinement, semconv discipline. Rules that cannot be escaped get weakened instead — the rule is loosened until the one honest exception fits, and then it no longer catches the dishonest ones. Rules that can be escaped silently are worse.

Decision

A boundary crossing that is genuinely correct is annotated in place:

resp, err := http.Get(u) //depcheck:allow netconfine the crawl politeness probe runs before the archive exists

The pragma sits on the offending line or the line above it, names one rule (or all), and must carry a written reason. A pragma naming an unknown rule, or carrying no reason, is itself a finding — it would otherwise suppress nothing while reading as though it did.

It is the source-level twin of a waiver entry in the harness this repository was judged by (golden/waivers.json, archived on golden-reference), and it is read the same way: as a cost, visible where the crossing is rather than in a config file nobody opens.

Consequences

  • Every rule keeps its strictness. The exception is local, named and explained, and it shows up in a diff of the file that takes it.
  • The pragma checker runs inside each analyzer's pass, so a typo'd rule name is caught by the pass it was addressed to rather than by a separate lint.
  • One pragma exists in the tree today — internal/generate/compose/compose_test.go suppressing semconvlit, because the point of that test case is a key the registry does not know and which by definition has no constant. A second one appearing is a thing to notice, not a thing to prevent.
  • Grepping //depcheck:allow is the standing inventory of accepted crossings, the same way the harness printed its waiver file on every run as the standing inventory of accepted divergences.