Enable depguard so a non-test file cannot import test support #59

clawbot · 2026-09-06T03:23:52+02:00

clawbot commented

2026-09-06 03:23:52 +02:00

depguard was in the disable list. It is now enabled with one rule,
test-support: in files that are neither test files nor inside a package whose
directory name ends in test, the imports named under deny are refused.
Canonical denies net/http/httptest, which serves tests only and is the same
in every repository.

This replaces internal/testimportgate in sneak/homoicon, a package whose only
job was to refuse a non-test Go file importing an in-module package whose last
path segment ends in test. sneak ruled on
sneak/homoicon#1029 that the rule moves into linter
configuration here.

depguard cannot express that rule generically. Its package lists are prefix
lists -- its own README says so, and I confirmed it: *test, **test and
$gomod/**test each match nothing, while a full import path matches. "In
module" is not generic either, since the module path differs per repository.
And depguard refuses a rule with no allow or deny list, so this file cannot
ship the rule pre-armed and empty for each repository to fill in.

The closest expressible rule is the one here. The file half is generic and
exact; the package half is a deny list each repository extends with its own
test-support packages, by full import path. REPO_POLICIES.md now says that list
is the one part of a vendored copy a repository may add to.

Tested with golangci-lint v2.12.2 on a scratch module: a production file
importing a denied *test package fails, and the same import from a _test.go
file and from inside the *test package passes. make check here is green.

Model: opus-5

`depguard` was in the disable list. It is now enabled with one rule, `test-support`: in files that are neither test files nor inside a package whose directory name ends in `test`, the imports named under `deny` are refused. Canonical denies `net/http/httptest`, which serves tests only and is the same in every repository. This replaces `internal/testimportgate` in sneak/homoicon, a package whose only job was to refuse a non-test Go file importing an in-module package whose last path segment ends in `test`. sneak ruled on https://git.eeqj.de/sneak/homoicon/issues/1029 that the rule moves into linter configuration here. depguard cannot express that rule generically. Its package lists are prefix lists -- its own README says so, and I confirmed it: `*test`, `**test` and `$gomod/**test` each match nothing, while a full import path matches. "In module" is not generic either, since the module path differs per repository. And depguard refuses a rule with no allow or deny list, so this file cannot ship the rule pre-armed and empty for each repository to fill in. The closest expressible rule is the one here. The file half is generic and exact; the package half is a deny list each repository extends with its own test-support packages, by full import path. REPO_POLICIES.md now says that list is the one part of a vendored copy a repository may add to. Tested with golangci-lint v2.12.2 on a scratch module: a production file importing a denied `*test` package fails, and the same import from a `_test.go` file and from inside the `*test` package passes. `make check` here is green. Model: opus-5

sneak was assigned by clawbot

2026-09-06 03:23:52 +02:00

clawbot added 1 commit 2026-09-06 03:23:52 +02:00

Enable depguard so a non-test file cannot import test support

check / check (push) Successful in 8s

Details

f1189a00e3

Test-support code exists to hand a test privileges the program itself
must never have, so it must not be compiled into the shipped binary.
depguard now states that rule: in files that are neither tests nor
inside a package whose directory name ends in test, the denied imports
are refused.

depguard matches an import path against a list of prefixes, so it
cannot be told "any path whose last segment ends in test". A repo's own
test-support packages therefore have to be named one at a time under
deny, by full import path, and the policy paragraph now says that list
is the one part of the vendored copy a repo may extend.

Requested by sneak on
sneak/homoicon#1029 to replace a
per-repository check written as a Go test.

Model: opus-5

clawbot referenced this issue from a commit

2026-09-06 04:00:18 +02:00

lint,store: the linter refuses a production import of test support (part of #1029)

clawbot referenced this issue from a commit

2026-09-06 05:24:12 +02:00

lint,store: the linter refuses a production import of test support (part of #1029)

clawbot referenced this issue from a commit

2026-09-06 05:40:49 +02:00

lint,store: the linter refuses a production import of test support (part of #1029)

sneak merged commit fbec5a523b into main

2026-09-08 05:14:43 +02:00

sneak deleted branch enable-depguard-test-support