Support forked-repo Travis build.

.travis.yml

@@ -6,20 +6,24 @@ go:
 services:
   - rabbitmq
 
+sudo: required
+
 matrix:
   fast_finish: true
 
-# Only build pushes to the master branch (and PRs)
-branches:
-  only:
-    - master
-
 before_install:
   - go get golang.org/x/tools/cmd/vet
   - go get golang.org/x/tools/cmd/cover
   - go get github.com/golang/lint/golint
   - go get github.com/mattn/goveralls
   - go get github.com/modocache/gover
+  # Boulder consists of multiple Go packages, which
+  # refer to each other by their absolute GitHub path,
+  # e.g. github.com/letsencrypt/boulder/analysis. That means, by default, if
+  # someone forks the repo, Travis won't pass on their own repo. To fix that,
+  # we add a symlink.
+  - mkdir -p $TRAVIS_BUILD_DIR $GOPATH/src/github.com/letsencrypt
+  - test ! -d $GOPATH/src/github.com/letsencrypt/boulder && ln -s $TRAVIS_BUILD_DIR $GOPATH/src/github.com/letsencrypt/boulder
 
 script:
   - make -j4 # Travis has 2 cores per build instance

Makefile

@@ -15,7 +15,7 @@ OBJECTS = activity-monitor \
 	ocsp-responder
 
 # Build environment variables (referencing core/util.go)
-BUILD_ID = $(shell git symbolic-ref --short HEAD) +$(shell git rev-parse --short HEAD)
+BUILD_ID = $(shell git symbolic-ref --short HEAD 2>/dev/null) +$(shell git rev-parse --short HEAD)
 BUILD_ID_VAR = github.com/letsencrypt/boulder/core.BuildID
 
 BUILD_HOST = $(shell whoami)@$(shell hostname)