fix: dev: better caching of ``_get_rec_depth``.

bin/compose-core

@@ -1378,13 +1378,17 @@ export -f get_service_deps
 ## XXXvlab: cache was disabled because improper. Indeed, this needs to cache
 ## 'depths' full state. Second, it should be
 _rec_get_depth() {
-    local elt=$1 dep deps max cache_file="$state_tmpdir/$FUNCNAME.cache.$1.$(declare -pA depths | md5_compat)"
+    local elt=$1 dep deps max
     [ "${depths[$elt]}" ] && return 0
-    if [ -e "$cache_file" ]; then
-        # debug "$FUNCNAME: cache hit ($*)"
+    local cache_file="$state_tmpdir/$FUNCNAME.cache.$1.$(declare -pA depths | md5_compat)"
+    if [ -e "$cache_file.depths" ]; then
+        #debug "$FUNCNAME: cache hit ($*) - $cache_file.depths"
         while read-0 k v; do
             depths["$k"]="$v"
-        done < "$cache_file"
+        done < "$cache_file.depths"
+        while read-0 k v; do
+            visited["$k"]="$v"
+        done < "$cache_file.visited"
         return 0
     fi
 
@@ -1410,7 +1414,10 @@ _rec_get_depth() {
     done
     # debug "Setting depth[$elt] to $((max + 1))"
     depths[$elt]=$((max + 1))
-    array_kv_to_stdin depths > $cache_file
+    array_kv_to_stdin depths > "$cache_file.depths"
+    array_kv_to_stdin visited > "$cache_file.visited"
+    # debug "DEPTHS: $(declare -pA depths)"
+    # debug "$FUNCNAME: caching hit ($*) - $cache_file"
 }
 export -f _rec_get_depth