fix: override=true must not needlessly delete a tag

If the tag to be set is exactly the same as the tag that exists, do
not delete it.

When the tag is recreated although it is not necessary, it may trigger
workflows that have already been triggered and send the workflow in a
loop.

- split `get_tag` & `matched_tag` out of ensure_tag
- in case of an override, only delete the tag if it fails `matched_tag`
- trace shell lines to help debug
- add testing

forgejo-release.sh

@@ -19,6 +19,8 @@ if ${VERBOSE:-false}; then set -x; fi
 : ${RETRY:=1}
 : ${DELAY:=10}
 
+TAG_FILE="$TMP_DIR/tag$$.json"
+
 export GNUPGHOME
 
 setup_tea() {
@@ -29,16 +31,35 @@ setup_tea() {
     fi
 }
 
+get_tag() {
+    if ! test -f "$TAG_FILE"; then
+        if api GET repos/$REPO/tags/"$TAG" >"$TAG_FILE"; then
+            echo "tag $TAG exists"
+        else
+            echo "tag $TAG does not exists"
+        fi
+    fi
+    test -s "$TAG_FILE"
+}
+
+matched_tag() {
+    if get_tag; then
+        local sha=$(jq --raw-output .commit.sha <"$TAG_FILE")
+        test "$sha" = "$SHA"
+    else
+        return 1
+    fi
+}
+
 ensure_tag() {
-    if api GET repos/$REPO/tags/"$TAG" >"$TMP_DIR"/tag.json; then
-        local sha=$(jq --raw-output .commit.sha <"$TMP_DIR"/tag.json)
-        if test "$sha" != "$SHA"; then
-            cat "$TMP_DIR"/tag.json
+    if get_tag; then
+        if ! matched_tag; then
+            cat "$TAG_FILE"
             echo "the tag SHA in the $REPO repository does not match the tag SHA that triggered the build: $SHA"
-            false
+            return 1
         fi
     else
-        api POST repos/$REPO/tags --data-raw '{"tag_name": "'"$TAG"'", "target": "'"$SHA"'"}'
+        api POST repos/$REPO/tags --data-raw '{"tag_name": "'"$TAG"'", "target": "'"$SHA"'"}' >"$TAG_FILE"
     fi
 }
 
@@ -112,7 +133,9 @@ maybe_override() {
         return
     fi
     api DELETE repos/$REPO/releases/tags/"$TAG" >&/dev/null || true
-    api DELETE repos/$REPO/tags/"$TAG" >&/dev/null || true
+    if get_tag && ! matched_tag; then
+        api DELETE repos/$REPO/tags/"$TAG"
+    fi
 }
 
 upload() {

testdata/forgejo-release-test.sh

@@ -45,15 +45,18 @@ test_ensure_tag() {
     # idempotent
     #
     ensure_tag
-    api GET repos/$REPO/tags/$TAG >$TMP_DIR/tag1.json
+    mv $TAG_FILE $TMP_DIR/tag1.json
+
     ensure_tag
-    api GET repos/$REPO/tags/$TAG >$TMP_DIR/tag2.json
+    mv $TAG_FILE $TMP_DIR/tag2.json
+
     diff -u $TMP_DIR/tag[12].json
     #
     # sanity check on the SHA of an existing tag
     #
     (
         SHA=12345
+        ! matched_tag
         ! ensure_tag
     )
     api DELETE repos/$REPO/tags/$TAG