Makefile: build completion scripts as part of (dyn)binary

Build the (cobra) generated completion scripts when building
the binaries, and store them inside build/completions.

Signed-off-by: Sebastiaan van Stijn <[email protected]>

Makefile

@@ -60,10 +60,12 @@ fmt: ## run gofumpt (if present) or gofmt
 .PHONY: binary
 binary: ## build executable for Linux
 	./scripts/build/binary
+	./scripts/build/completion
 
 .PHONY: dynbinary
 dynbinary: ## build dynamically linked binary
 	GO_LINKMODE=dynamic ./scripts/build/binary
+	./scripts/build/completion
 
 .PHONY: plugins
 plugins: ## build example CLI plugins
@@ -88,13 +90,18 @@ authors: ## generate AUTHORS file from git history
 
 .PHONY: completion
 completion: binary
-completion: /etc/bash_completion.d/docker
 completion: ## generate and install the completion scripts
-
-.PHONY: /etc/bash_completion.d/docker
-/etc/bash_completion.d/docker: ## generate and install the bash-completion script
-	mkdir -p /etc/bash_completion.d
-	docker completion bash > /etc/bash_completion.d/docker
+# Note: this uses system-wide paths, and so may overwrite completion
+# scripts installed as part of deb/rpm packages.
+#
+# Given that this target is intended to debug/test updated versions, we could
+# consider installing in per-user (~/.config, XDG_DATA_DIR) paths instead, but
+# this will add more complexity.
+#
+# See https://github.com/docker/cli/pull/5770#discussion_r1927772710
+	install -D -p -m 0644 ./build/completion/bash/docker /usr/share/bash-completion/completions/docker
+	install -D -p -m 0644 ./build/completion/fish/docker.fish debian/docker-ce-cli/usr/share/fish/vendor_completions.d/docker.fish
+	install -D -p -m 0644 ./build/completion/zsh/_docker debian/docker-ce-cli/usr/share/zsh/vendor-completions/_docker
 
 .PHONY: manpages
 manpages: ## generate man pages from go source and markdown

scripts/build/completion

@@ -0,0 +1,19 @@
+#!/usr/bin/env sh
+#
+# Build the shell completion scripts
+#
+
+set -eu
+
+. ./scripts/build/.variables
+
+# generate the shell completion scripts and store them in build/completion.
+if [ "$(go env GOOS)" != "windows" ]; then
+		if [ ! -f ./build/docker ]; then
+				echo "Run 'make binary' or 'make dynbinary' first"
+		fi
+
+		./build/docker completion bash | install -D /dev/stdin build/completion/bash/docker
+		./build/docker completion zsh | install -D /dev/stdin build/completion/zsh/_docker
+		./build/docker completion fish | install -D /dev/stdin build/completion/fish/docker.fish
+fi