Refactor Makefile install rule

Check for older installation of the tools and only install them if
missing or if the versions don't match

.travis.yml

@@ -5,6 +5,9 @@ rust:
   - beta
   - nightly
 
+env:
+  - NO_RUSTUP=1
+
 cache: cargo
 
 matrix:
@@ -13,7 +16,7 @@ matrix:
     - rust: beta
 
 before_script:
-  - NO_RUSTUP=1 ./scripts/travis/before_script.sh
+  - ./scripts/travis/before_script.sh
 
 script:
-  - NO_RUSTUP=1 ./scripts/travis/script.sh
+  - ./scripts/travis/script.sh

Makefile

@@ -30,18 +30,45 @@ help: ## Print all the available commands
 # ================================ Tools ======================================
 
 
-CLIPPY_VERSION = 0.0.134
-RUSTFMT_VERSION = 0.8.4
-
 install: install-rustfmt install-clippy ## Install tools dependencies
 
+RUSTFMT_TARGET_VERSION = 0.8.4
+RUSTFMT = $(shell command -v rustfmt 2> /dev/null)
+ifeq ("$(RUSTFMT)","")
+  RUSTFMT_INSTALL_CMD = @echo "Installing rustfmt $(RUSTFMT_TARGET_VERSION)" \
+			&& $(CARGO) install --vers $(RUSTFMT_TARGET_VERSION) --force rustfmt
+else
+  RUSTFMT_CURRENT_VERSION = $(shell rustfmt --version | sed 's/^\(.*\) ()/\1/')
+  ifeq ($(RUSTFMT_CURRENT_VERSION),$(RUSTFMT_TARGET_VERSION))
+    RUSTFMT_INSTALL_CMD = @echo "Rustfmt is up to date"
+  else
+    RUSTFMT_INSTALL_CMD = @echo "Updating rustfmt from $(RUSTFMT_CURRENT_VERSION) to $(RUSTFMT_TARGET_VERSION)" \
+			  && $(CARGO) install --vers $(RUSTFMT_TARGET_VERSION) --force rustfmt
+  endif
+endif
+
 install-rustfmt: RUST_CHANNEL = nightly
 install-rustfmt: ## Intall rustfmt
-	$(CARGO) install --vers $(RUSTFMT_VERSION) --force rustfmt
+	$(RUSTFMT_INSTALL_CMD)
+
+
+CLIPPY_TARGET_VERSION = 0.0.134
+CLIPPY_CURRENT_VERSION = $(shell $(CARGO) clippy --version 2>/dev/null)
+ifeq ("$(CLIPPY_CURRENT_VERSION)","")
+  CLIPPY_INSTALL_CMD = @echo "Installing clippy $(CLIPPY_TARGET_VERSION)" \
+		       && $(CARGO) install --vers $(CLIPPY_TARGET_VERSION) --force clippy
+else
+  ifeq ($(CLIPPY_CURRENT_VERSION),$(CLIPPY_TARGET_VERSION))
+    CLIPPY_INSTALL_CMD = @echo "Clippy is up to date"
+  else
+    CLIPPY_INSTALL_CMD = @echo "Updating clippy from $(CLIPPY_CURRENT_VERSION) to $(CLIPPY_TARGET_VERSION)" \
+			 && $(CARGO) install --vers $(CLIPPY_TARGET_VERSION) --force clippy
+  endif
+endif
 
 install-clippy: RUST_CHANNEL = nightly
 install-clippy: ## Install clippy
-	$(CARGO) install --vers $(CLIPPY_VERSION) --force clippy
+	$(CLIPPY_INSTALL_CMD)
 
 
 # =============================== Build =======================================

scripts/travis/script.sh

@@ -2,8 +2,6 @@
 
 set -eu
 
-make build
-make test
 if [[ "$TRAVIS_RUST_VERSION" == "nightly" ]]; then
   make lint
 fi