perf: replace goheader linter with custom check

[silverwind]

Replace the slow goheader linter with a custom check.

Local go lint time is down from 247s to 32s. 6 new files that were previously undetected because of //go:build ignore are fixed. The exit code of the make target preserves the golangci-lint exit code, if present.

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This PR was written with the help of Claude Opus 4.7

[Copilot]

Pull request overview

This PR replaces the goheader golangci-lint linter with a custom Go header-checker to significantly reduce Go lint runtime, while updating a few files/templates to match the required header layout.

Changes:

• Added a standalone header checker (tools/lint-go-header.go) that scans .go files for the expected copyright + SPDX header.
• Updated make lint-go / make lint-go-fix to run the new header checker alongside golangci-lint and preserve golangci-lint’s exit code when it fails.
• Adjusted several Go files and generator templates to ensure the header appears before other leading comments/build tags; removed goheader from enabled linters.

Reviewed changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
tools/lint-go-header.go	New custom header linter (filesystem walk + regex match).
Makefile	Runs the custom header linter in lint-go / lint-go-fix and combines exit codes.
.golangci.yml	Disables the goheader linter.
modules/charset/generate/generate.go	Updates generator templates so generated files place the license header first.
modules/charset/ambiguous_gen.go	Reorders generated-file header to match new expectations.
modules/charset/invisible_gen.go	Reorders generated-file header to match new expectations.
modules/auth/pam/pam_test.go	Moves build tag below the license header.
models/db/driver_sqlite_modernc.go	Moves build tag below the license header.
models/db/driver_sqlite_mattn.go	Moves build tag below the license header.
build/generate-gitignores.go	Adds missing license header to an ignore build-tagged tool.

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[Copilot]

Pull request overview

Copilot reviewed 11 out of 11 changed files in this pull request and generated 2 comments.

Comments suppressed due to low confidence (1)

tools/lint-go.sh:19

• lint-go.sh hard-codes invoking go/go run instead of respecting the Makefile’s $(GO) override (used throughout the build for toolchain pinning/wrappers). This change makes make GO=... lint-go behave differently from other targets; consider passing GO through from the Makefile and using it consistently inside the script.

if [ -n "$LINT_GO_INSTALL" ]; then
	GOOS= GOARCH= go install "$GOLANGCI_LINT_PACKAGE"
	GOOS= GOARCH= go run tools/lint-go-header.go; header=$?
	golangci-lint run "$@"; lint=$?
else
	go run tools/lint-go-header.go; header=$?
	go run "$GOLANGCI_LINT_PACKAGE" run "$@"; lint=$?
fi

exit $((lint ? lint : header))

[silverwind]

At minimum make it silent, output on success should be

0 issues.
0 issues.

[silverwind]

Planning to implement the header check as minimal fast golangci-lint plugin. Per golangci-lint's design bug, it will not work on files with //go:build ignore, but that's fine. Having the plugin infrastructure now will enable us to easily write more custom linters later.

dismiss

[silverwind]

Given that the slow lint issue is very cumbersome for current development, let's merge this now. I'm not happy with the verbosity and local windows run but the speed gain is more important. I will follow up with the plugin rewrite.

[wxiaoguang]

OK, my philosophy is: as long as nothing blocks, the design doesn't introduce new problems, nothing worse, then good to merge.

[silverwind]

my philosophy is: as long as nothing blocks, the design doesn't introduce new problems, nothing worse, then good to merge.

No, your philosophy is as long as it's not absolutely perfect, you block it 😆.

[silverwind]

Admins need to remove lint-go-gogit and lint-go-windows from required check before this can merge.