unconditionally create git tag

if the travis build passed, we want to create a git tag regardless of
whether or not a crate was published

then publish the crate only if the git tag didn't previously exist

.travis/publish_crate.sh

@@ -4,21 +4,27 @@ set -o errexit -o nounset
 
 ([[ $TRAVIS_BRANCH != "master" ]] || [[ $TRAVIS_PULL_REQUEST != "false" ]]) && exit 0
 
-cargo login $CRATESIO_TOKEN
+version=$(cat Cargo.toml | awk -F'"' '/version/{print $2}')
 
-if cargo publish; then
-  echo "Published new version on crates.io"
-
-  echo "Creating new git tag"
-  version=$(cat Cargo.toml | awk -F'"' '/version/{print $2}')
+if ! git rev-parse $version > /dev/null 2>&1; then
+  echo "Creating new git tag $version"
 
   git config user.name "Jorge Israel Peña"
   git config user.email "[email protected]"
 
   git remote add upstream "https://$GH_TOKEN@github.com/blaenk/hoedown.git"
   git tag -a "v$version" -m "published https://crates.io/crates/hoedown/$version"
   git push upstream --tags
+
+  echo "Publishing to crates.io"
+
+  cargo login $CRATESIO_TOKEN
+
+  if cargo publish; then
+    echo "Published new version on crates.io"
+  else
+    echo "Error; Perhaps version already exists?"
+  fi
 else
-  echo "Version already existed"
+    echo "Tag $version already exists; no tag created, no crate published"
 fi
-