ci: fix mod-check

GitLab probably blocked GitHub's CI runner IP address. So we can't download
packages from GitLab directly during this check. Workaround applied: download
these particular packages from proxy.golang.org which works in CI.

Author: starius

Makefile

@@ -14,6 +14,71 @@ GOIMPORTS_BIN := $(GO_BIN)/gosimports
 GOBUILD := CGO_ENABLED=0 GO111MODULE=on go build -v
 GOINSTALL := CGO_ENABLED=0 GO111MODULE=on go install -v
 GOMOD := GO111MODULE=on go mod
+# GitLab-backed module sources can reject CI runner traffic. Seed known
+# GitLab and modernc.org modules through the public Go proxy before the
+# direct check.
+MOD_CHECK_PREFETCH := \
+	gitlab.com/bosi/decorder@v0.4.2 \
+	gitlab.com/nyarla/go-crypt@v0.0.0-20160106005555-d9a5dc2b789b \
+	gitlab.com/yawning/bsaes.git@v0.0.0-20190805113838-0a714cd429ec \
+	modernc.org/b@v1.0.0 \
+	modernc.org/cc/v3@v3.36.0 \
+	modernc.org/cc/v3@v3.36.2 \
+	modernc.org/cc/v3@v3.36.3 \
+	modernc.org/cc/v3@v3.41.0 \
+	modernc.org/cc/v4@v4.20.0 \
+	modernc.org/cc/v4@v4.21.4 \
+	modernc.org/ccgo/v3@v3.0.0-20220428102840-41399a37e894 \
+	modernc.org/ccgo/v3@v3.0.0-20220430103911-bc99d88307be \
+	modernc.org/ccgo/v3@v3.16.4 \
+	modernc.org/ccgo/v3@v3.16.6 \
+	modernc.org/ccgo/v3@v3.16.8 \
+	modernc.org/ccgo/v3@v3.16.9 \
+	modernc.org/ccgo/v3@v3.17.0 \
+	modernc.org/ccgo/v4@v4.16.0 \
+	modernc.org/ccgo/v4@v4.19.2 \
+	modernc.org/ccorpus@v1.11.6 \
+	modernc.org/db@v1.0.0 \
+	modernc.org/file@v1.0.0 \
+	modernc.org/fileutil@v1.3.0 \
+	modernc.org/gc/v2@v2.4.1 \
+	modernc.org/gc/v3@v3.0.0-20240107210532-573471604cb6 \
+	modernc.org/golex@v1.0.0 \
+	modernc.org/httpfs@v1.0.6 \
+	modernc.org/internal@v1.0.0 \
+	modernc.org/libc@v0.0.0-20220428101251-2d5f3daf273b \
+	modernc.org/libc@v1.16.0 \
+	modernc.org/libc@v1.16.1 \
+	modernc.org/libc@v1.16.17 \
+	modernc.org/libc@v1.16.19 \
+	modernc.org/libc@v1.17.0 \
+	modernc.org/libc@v1.17.1 \
+	modernc.org/libc@v1.49.3 \
+	modernc.org/libc@v1.55.3 \
+	modernc.org/lldb@v1.0.0 \
+	modernc.org/mathutil@v1.2.2 \
+	modernc.org/mathutil@v1.4.1 \
+	modernc.org/mathutil@v1.5.0 \
+	modernc.org/mathutil@v1.6.0 \
+	modernc.org/memory@v1.1.1 \
+	modernc.org/memory@v1.2.0 \
+	modernc.org/memory@v1.2.1 \
+	modernc.org/memory@v1.8.0 \
+	modernc.org/opt@v0.1.1 \
+	modernc.org/opt@v0.1.3 \
+	modernc.org/ql@v1.0.0 \
+	modernc.org/sortutil@v1.2.0 \
+	modernc.org/sqlite@v1.18.1 \
+	modernc.org/sqlite@v1.29.10 \
+	modernc.org/sqlite@v1.34.5 \
+	modernc.org/strutil@v1.1.1 \
+	modernc.org/strutil@v1.1.3 \
+	modernc.org/strutil@v1.2.0 \
+	modernc.org/tcl@v1.13.1 \
+	modernc.org/token@v1.0.0 \
+	modernc.org/token@v1.1.0 \
+	modernc.org/z@v1.5.1 \
+	modernc.org/zappy@v1.0.0
 
 COMMIT := $(shell git describe --abbrev=40 --dirty --tags)
 COMMIT_HASH := $(shell git rev-parse HEAD)
@@ -156,6 +221,9 @@ mod-tidy:
 
 mod-check:
 	@$(call print, "Checking modules.")
+	@set -e; for module in $(MOD_CHECK_PREFETCH); do \
+		GOPROXY=https://proxy.golang.org $(GOMOD) download $$module; \
+	done
 	GOPROXY=direct $(GOMOD) tidy
 	cd swapserverrpc/ && GOPROXY=direct $(GOMOD) tidy
 	cd looprpc/ && GOPROXY=direct $(GOMOD) tidy