Updates for OR-Tools v8.2

 * Update go protobuf -> `1.5.2`
 * Update go -> `1.16.3`
 * Makefile, Go Dockerfile, + Airspace Readme updates

AIRSPACE-README.md

@@ -19,11 +19,11 @@ It has Go bindings and binaries for use with Go projects.
  1. Install SWIG 4.0.1:
     `brew install swig`
  1. Install protobuf for Go:
-    `go get github.com/golang/protobuf/protoc-gen-go@v1.3`
+    `go get -u github.com/golang/protobuf/protoc-gen-go@v1.5.2`
  1. Clone Airspace OR-tools:
     `git clone [email protected]:AirspaceTechnologies/or-tools.git`
  1. Make third party:
-    `make third_party`
+    `make clean_third_party third_party`
  1. Make go:
     `make clean_go go`
  1. Make go tests:
@@ -37,5 +37,24 @@ It has Go bindings and binaries for use with Go projects.
     `make golib_archive`
  1. Log into Github and create a release with the resulting binaries
 
+## Update Fork from Upstream
+ 1. Configure git remote pointing to upstream or-tools repo:
+    `git remote add upstream [email protected]:google/or-tools.git`
+ 1. Fetch upstream:
+    `git fetch upstream`
+ 1. Checkout fork's `stable` branch and pull:
+    `git checkout stable && git pull`
+ 1. Merge changes from upstream `stable` branch:
+    `git merge upstream/stable`
+ 1. Push fork's `stable` branch:
+    `git push`
+ 1. Checkout fork's `airspace` branch and pull:
+    `git checkout airspace && git pull`
+ 1. Merge changes from `stable` to `airspace` branch:
+    `git merge stable`
+ 1. Push fork's `airspace` branch:
+    `git push`
+ 1. Optionally build and release using steps above
+
 ## TODO
  1. Make `IntVar`->`IntExpr` casting cleaner

makefiles/Makefile

@@ -110,7 +110,7 @@ LANGUAGES = cpp python java dotnet go
 ## PRESTAGES ##
 ###############
 PRESTAGES = base swig
-define make-prestage-target =
+define make-prestage-target
 #$$(info STAGE: $1)
 #$$(info Create targets: $1 $(addsuffix _$1, $(DISTROS)).)
 targets_$1 = $(addsuffix _$1, $(DISTROS))
@@ -151,7 +151,7 @@ $(foreach stage,$(PRESTAGES),$(eval $(call make-prestage-target,$(stage))))
 ## STAGES ##
 ############
 STAGES = env devel build test package export
-define make-stage-target =
+define make-stage-target
 #$$(info STAGE: $1)
 #$$(info Create targets: $1 $(addsuffix _$1, $(DISTROS)).)
 targets_$1 = $(addsuffix _$1, $(DISTROS))

makefiles/Makefile.go.mk

@@ -279,7 +279,8 @@ go_pimpl: $(GEN_DIR)/ortools/go
 
 $(GEN_DIR)/ortools/go/go.mod:
 	cd $(GEN_DIR)/ortools/go && \
-	$(GO_BIN) mod init $(PKG_ROOT)
+	$(GO_BIN) mod init $(PKG_ROOT) && \
+	$(GO_BIN) mod tidy
 
 $(GEN_DIR)/ortools/go: \
  $(LIB_DIR)/$(LIB_PREFIX)$(GO_OR_TOOLS_NATIVE_LIB).$(SWIG_GO_LIB_SUFFIX) \
@@ -352,7 +353,7 @@ detect_go:
 	@echo Relevant info for the Go build:
 	@echo These must resolve to proceed
 	@echo "  Install go: https://golang.org/doc/install"
-	@echo "  Install protoc-gen-go: 'go get -u github.com/golang/protobuf/protoc-gen-go'"
+	@echo "  Install protoc-gen-go: 'go get -u github.com/golang/protobuf/protoc-gen-go@v1.5.2'"
 	@echo GO_BIN = $(GO_BIN)
 	@echo GO_PATH = $(GO_PATH)
 	@echo PROTOC_GEN_GO = $(PROTOC_GEN_GO)

makefiles/docker/debian/go.Dockerfile

@@ -3,12 +3,12 @@ ENV GOROOT=/usr/local/go
 ENV GOPATH=/home/go
 ENV PATH=$PATH:$GOROOT/bin:$GOPATH/bin
 ENV GO111MODULE=on
-RUN wget https://dl.google.com/go/go1.14.1.linux-amd64.tar.gz \
+RUN wget https://golang.org/dl/go1.16.3.linux-amd64.tar.gz \
     && mkdir -p /usr/local/go \
     && mkdir -p /home/go \
-    && tar -xvf go1.14.1.linux-amd64.tar.gz -C /usr/local \
-    && rm -rf go1.14.1.linux-amd64.tar.gz \
-    && go get github.com/golang/protobuf/protoc-gen-go@v1.3
+    && tar -xvf go1.16.3.linux-amd64.tar.gz -C /usr/local \
+    && rm -rf go1.16.3.linux-amd64.tar.gz \
+    && go get github.com/golang/protobuf/protoc-gen-go@v1.5.2
 RUN make -version
 
 FROM env AS devel