Improve 'updatepacmetafromspec' command to expand rpm spec macros by calling rpmspec to query the data

contrib/osc.spec

@@ -111,6 +111,9 @@ Recommends:     obs-service-source_validator
 Recommends:     obs-service-tar_scm
 Recommends:     obs-service-verify_file
 
+# needed for `osc updatepacmetafromspec` that calls rpmspec to get values with expanded macros
+Recommends:     rpm-build
+
 # needed for ssh signature auth
 Recommends:     %{ssh_add_pkg}
 Recommends:     %{ssh_keygen_pkg}

osc/core.py

@@ -1862,6 +1862,19 @@ def read_meta_from_spec(specfile, *args):
     if not os.path.isfile(specfile):
         raise oscerr.OscIOError(None, f'\'{specfile}\' is not a regular file')
 
+    rpmspec_path = shutil.which("rpmspec")
+    if rpmspec_path:
+        result = {}
+        for arg in args:
+            # convert tag to lower case and remove the leading '%'
+            tag = arg.lower().lstrip("%")
+            cmd = [rpmspec_path, "-q", specfile, "--srpm", "--qf", "%{" + tag + "}"]
+            value = subprocess.check_output(cmd, encoding="utf-8")
+            if value == "(none)":
+                value = ""
+            result[arg] = value
+        return result
+
     try:
         lines = codecs.open(specfile, 'r', locale.getpreferredencoding()).readlines()
     except UnicodeDecodeError: