Rebuild jaeger-ui if the tree does not match any tag exactly

The previous behavior resulted in the prebuild upstream package
being downloaded, even if the local tree has any changes,
whether they are commited or not. This broke our internal
build that has some patches applied. See:

* #4251 (comment)

Let's use a more strict approach and only use the prebuild package
if the tag is exact and does not contain any extra changes.

Signed-off-by: Ivan Babrou <github@ivan.computer>

scripts/rebuild-ui.sh

@@ -4,13 +4,13 @@ set -euxf -o pipefail
 
 cd jaeger-ui
 
-LAST_TAG=$(git describe --abbrev=0 --tags 2>/dev/null)
-BRANCH_HASH=$(git rev-parse HEAD)
-LAST_TAG_HASH=$(git rev-parse $LAST_TAG)
+LAST_TAG=$(git describe --tags --dirty 2>/dev/null)
 
-if [[ "$BRANCH_HASH" == "$LAST_TAG_HASH" ]]; then
-
-    if [[ "$LAST_TAG" =~ ^v[0-9]+\.[0-9]+\.[0-9]+$ ]];  then
+if [[ "$LAST_TAG" =~ ^v[0-9]+\.[0-9]+\.[0-9]+$ ]];  then
+    BRANCH_HASH=$(git rev-parse HEAD)
+    LAST_TAG_HASH=$(git rev-parse $LAST_TAG)
+
+    if [[ "$BRANCH_HASH" == "$LAST_TAG_HASH" ]]; then
         temp_file=$(mktemp)
         trap "rm -f ${temp_file}" EXIT
         release_url="https://github.com/jaegertracing/jaeger-ui/releases/download/${LAST_TAG}/assets.tar.gz"
@@ -20,16 +20,9 @@ if [[ "$BRANCH_HASH" == "$LAST_TAG_HASH" ]]; then
             rm -r -f packages/jaeger-ui/build/
             tar -zxvf "$temp_file" packages/jaeger-ui/build/
             exit 0
-
         fi
     fi
-
 fi
 
 # do a regular full build
 yarn install --frozen-lockfile && cd packages/jaeger-ui && yarn build
-
-
-
-
-