rewrite using "with-go-mod.sh" script and "go run"

Use the same script as is used in moby/moby, which more gracefully
handles an existing `go.mod` (which can be symlinked) into account.

- keep the scripts called generic, and update the Makefile to invoke
  them with the "with-go-mod.sh" script.
- use "go run" instead of building temporary binaries
- check if go-md2man exists before building a binary

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

Author: thaJeztah

Makefile

@@ -67,20 +67,20 @@ dynbinary: ## build dynamically linked binary
 
 .PHONY: plugins
 plugins: ## build example CLI plugins
-	./scripts/build/plugins
+	scripts/build/plugins
 
 .PHONY: vendor
 vendor: ## update vendor with go modules
 	rm -rf vendor
-	./scripts/vendor update
+	scripts/with-go-mod.sh scripts/vendor update
 
 .PHONY: validate-vendor
 validate-vendor: ## validate vendor
-	./scripts/vendor validate
+	scripts/with-go-mod.sh scripts/vendor validate
 
 .PHONY: mod-outdated
 mod-outdated: ## check outdated dependencies
-	./scripts/vendor outdated
+	scripts/with-go-mod.sh scripts/vendor outdated
 
 .PHONY: authors
 authors: ## generate AUTHORS file from git history
@@ -115,15 +115,15 @@ shell-completion: ## generate shell-completion scripts
 
 .PHONY: manpages
 manpages: ## generate man pages from go source and markdown
-	scripts/docs/generate-man.sh
+	scripts/with-go-mod.sh scripts/docs/generate-man.sh
 
 .PHONY: mddocs
 mddocs: ## generate markdown files from go source
-	scripts/docs/generate-md.sh
+	scripts/with-go-mod.sh scripts/docs/generate-md.sh
 
 .PHONY: yamldocs
 yamldocs: ## generate documentation YAML files consumed by docs repo
-	scripts/docs/generate-yaml.sh
+	scripts/with-go-mod.sh scripts/docs/generate-yaml.sh
 
 .PHONY: help
 help: ## print this help

dockerfiles/Dockerfile.vendor

@@ -16,7 +16,7 @@ RUN --mount=target=/context \
     --mount=target=/go/pkg/mod,type=cache <<EOT
 set -e
 rsync -a /context/. .
-./scripts/vendor update
+./scripts/with-go-mod.sh ./scripts/vendor update
 mkdir /out
 cp -r vendor.mod vendor.sum vendor /out
 EOT
@@ -32,12 +32,12 @@ rsync -a /context/. .
 git add -A
 rm -rf vendor
 cp -rf /out/* .
-./scripts/vendor validate
+./scripts/with-go-mod.sh ./scripts/vendor validate
 EOT
 
 FROM psampaz/go-mod-outdated:${MODOUTDATED_VERSION} AS go-mod-outdated
 FROM base AS outdated
 RUN --mount=target=.,rw \
     --mount=target=/go/pkg/mod,type=cache \
     --mount=from=go-mod-outdated,source=/home/go-mod-outdated,target=/usr/bin/go-mod-outdated \
-    ./scripts/vendor outdated
+    ./scripts/with-go-mod.sh ./scripts/vendor outdated

scripts/docs/generate-man.sh

@@ -2,23 +2,21 @@
 
 set -eu
 
-: "${MD2MAN_VERSION=v2.0.6}"
+: "${GO_MD2MAN:=go-md2man}"
 
-function clean() {
-	rm -f go.mod
-}
-
-export GO111MODULE=auto
-trap clean EXIT
-
-./scripts/vendor init
-# build gen-manpages
-go build -mod=vendor -modfile=vendor.mod -tags manpages -o /tmp/gen-manpages ./man/generate.go
-# build go-md2man
-go build -mod=vendor -modfile=vendor.mod -o /tmp/go-md2man ./vendor/github.com/cpuguy83/go-md2man/v2
+if ! command -v "$GO_MD2MAN" > /dev/null; then
+  (
+    set -x
+    go build -mod=vendor -modfile=vendor.mod -o ./build/tools/go-md2man ./vendor/github.com/cpuguy83/go-md2man/v2
+  )
+  GO_MD2MAN=$(realpath ./build/tools/go-md2man)
+fi
 
 mkdir -p man/man1
-(set -x ; /tmp/gen-manpages --root "." --target "$(pwd)/man/man1")
+(
+  set -x
+  go run -mod=vendor -modfile=vendor.mod -tags manpages ./man/generate.go --root "." --target "./man/man1"
+)
 
 (
   cd man
@@ -31,6 +29,9 @@ mkdir -p man/man1
       continue
     fi
     mkdir -p "./man${num}"
-    (set -x ; /tmp/go-md2man -in "$FILE" -out "./man${num}/${name}")
+    (
+      set -x ;
+      "$GO_MD2MAN" -in "$FILE" -out "./man${num}/${name}"
+    )
   done
 )

scripts/docs/generate-md.sh

@@ -2,22 +2,9 @@
 
 set -eu
 
-: "${CLI_DOCS_TOOL_VERSION=v0.9.0}"
-
-function clean() {
-	rm -f go.mod
-}
-
-export GO111MODULE=auto
-trap clean EXIT
-
-./scripts/vendor init
-# build docsgen
-go build -mod=vendor -modfile=vendor.mod -tags docsgen -o /tmp/docsgen ./docs/generate/generate.go
-
 (
   set -x
-  /tmp/docsgen --formats md --source "$(pwd)/docs/reference/commandline" --target "$(pwd)/docs/reference/commandline"
+  go run -mod=vendor -modfile=vendor.mod -tags docsgen ./docs/generate/generate.go --formats md --source "./docs/reference/commandline" --target "./docs/reference/commandline"
 )
 
 # remove generated help.md file

scripts/docs/generate-yaml.sh

@@ -2,19 +2,6 @@
 
 set -eu
 
-: "${CLI_DOCS_TOOL_VERSION=v0.9.0}"
-
-function clean() {
-	rm -f go.mod
-}
-
-export GO111MODULE=auto
-trap clean EXIT
-
-./scripts/vendor init
-# build docsgen
-go build -mod=vendor -modfile=vendor.mod -tags docsgen -o /tmp/docsgen ./docs/generate/generate.go
-
 mkdir -p docs/yaml
 set -x
-/tmp/docsgen --formats yaml --source "$(pwd)/docs/reference/commandline" --target "$(pwd)/docs/yaml"
+go run -mod=vendor -modfile=vendor.mod -tags docsgen ./docs/generate/generate.go --formats yaml --source "./docs/reference/commandline" --target "./docs/yaml"

scripts/vendor

@@ -13,15 +13,6 @@ if [ -z "$TYP" ]; then
   usage
 fi
 
-init() {
-  # create dummy go.mod, see comment in vendor.mod
-  cat > go.mod <<EOL
-module github.com/docker/cli
-
-go 1.23.0
-EOL
-}
-
 update() {
   (set -x ; go mod tidy -modfile=vendor.mod; go mod vendor -modfile=vendor.mod)
 }
@@ -44,20 +35,14 @@ outdated() {
 }
 
 case $TYP in
-  "init")
-    init
-    ;;
   "update")
-    init
     update
     ;;
   "validate")
-    init
     update
     validate
     ;;
   "outdated")
-    init
     outdated
     ;;
   *)

scripts/with-go-mod.sh

@@ -0,0 +1,33 @@
+#!/usr/bin/env bash
+#
+# This script is used to coerce certain commands which rely on the presence of
+# a go.mod into working with our repository. It works by creating a fake
+# go.mod, running a specified command (passed via arguments), and removing it
+# when the command is finished. This script should be dropped when this
+# repository is a proper Go module with a permanent go.mod.
+
+set -e
+
+SCRIPTDIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+ROOTDIR="$(cd "${SCRIPTDIR}/.." && pwd)"
+
+if test -e "${ROOTDIR}/go.mod"; then
+	{
+		scriptname=$(basename "$0")
+		cat >&2 <<- EOF
+			$scriptname: WARN: go.mod exists in the repository root!
+			$scriptname: WARN: Using your go.mod instead of our generated version -- this may misbehave!
+		EOF
+	} >&2
+else
+	set -x
+
+	tee "${ROOTDIR}/go.mod" >&2 <<- EOF
+		module github.com/docker/cli
+
+		go 1.23.0
+	EOF
+	trap 'rm -f "${ROOTDIR}/go.mod"' EXIT
+fi
+
+GO111MODULE=on GOTOOLCHAIN=local "$@"