Add rules for uploading to hackage

While it would be really nice to run this from CI,
The only way to upload a package involves using account-wide credentials.
We can either use a username/password, or an API token.
Both of these credentials have the same privileges,
and that's too much power to give to CI.

For now, we run this from the local machine.
Maybe we can think of another way that's a bit safer.

.circleci/config.yml

@@ -1,5 +1,14 @@
 version: 2
 jobs:
+  sdist:
+    docker:
+      - image: haskell:8.2.2
+    steps:
+      - checkout
+      - run:
+          name: Build sdist
+          command: make sdist
+
   test:
     docker:
       - image: haskell:8.2.2
@@ -20,8 +29,10 @@ jobs:
           paths:
             - .stack-work
             - /root/.stack
+
 workflows:
   version: 2
   base:
     jobs:
+      - sdist
       - test

Makefile

@@ -1,4 +1,9 @@
+PROJECT_NAME := rollbar-hs
+
 BIN := bin
+CABAL := cabal
+CABAL_FILE := $(PROJECT_NAME).cabal
+DIST := dist
 EMPTY := .make
 GHCID := $(BIN)/ghcid
 STACK := stack
@@ -6,30 +11,55 @@ STACK_WORK := .stack-work
 
 .DEFAULT_GOAL := build
 
+$(BIN):
+	mkdir -p $@
+
+$(DIST):
+	mkdir -p $@
+
 $(EMPTY):
-	mkdir $@
+	mkdir -p $@
 
 $(EMPTY)/stack-setup: | $(EMPTY)
 	$(STACK) setup
 	touch $@
 
-$(GHCID): $(EMPTY)/stack-setup
+$(GHCID): $(EMPTY)/stack-setup | $(BIN)
 	$(STACK) install ghcid --local-bin-path $(BIN)
 
+$(CABAL_FILE):
+	# `stack` has no way to run `hpack` directly.
+	# We can run `hpack` indirectly with little overhead.
+	$(STACK) build --dry-run
+
 .PHONY: build
 build: $(EMPTY)/stack-setup
 	$(STACK) build --no-run-tests --test
 
+.PHONY: cabal-check
+cabal-check: $(CABAL_FILE)
+	$(CABAL) check
+
 .PHONY: clean
 clean:
-	rm -f $(BIN)/*
-	rm -f $(EMPTY)/*
+	rm -f $(CABAL_FILE)
+	rm -fr $(BIN)
+	rm -fr $(DIST)
+	rm -fr $(EMPTY)
 	rm -fr $(STACK_WORK)
 
+.PHONY: sdist
+sdist: cabal-check | $(DIST)
+	$(CABAL) sdist
+
 .PHONY: test
 test: build
 	$(STACK) test
 
+.PHONY: upload-hackage
+upload-hackage: sdist
+	@ $(CABAL) upload $(DIST)/$(PROJECT_NAME)-*.tar.gz
+
 .PHONY: watch
 watch: $(GHCID)
 	$(GHCID)