fix package digest when running from source tree

unfurl/server/serve.py

@@ -500,7 +500,7 @@ class CacheValue(NamedTuple):
     last_commit_date: int
 
     def make_etag(self) -> str:
-        etag = int(self.last_commit, 16) ^ int(get_package_digest(True), 16)
+        etag = int(self.last_commit, 16) ^ int(get_package_digest(True) or "0", 16)
         for dep in self.deps.values():
             for last_commit in dep.last_commits:
                 if last_commit:

unfurl/util.py

@@ -87,13 +87,16 @@ def get_package_digest(commit_only=False) -> str:
             _package_digest = repo.git.log(n=1, pretty="format:%h")
         else:
             _package_digest = repo.git.describe("--dirty", "--always", "--match=v*")
-
-    try:
-        pbr = [p for p in files("unfurl") if "pbr.json" in str(p)][0]  # type: ignore  # Ignored because of the try/except
-        _package_digest = json.loads(pbr.read_text())["git_version"]
-    except Exception:
+    else:
         _package_digest = ""
-    return cast(str, _package_digest)
+        pkg_files = files("unfurl")
+        if pkg_files:
+            try:
+                pbr = [p for p in pkg_files if "pbr.json" in str(p)][0]
+                _package_digest = json.loads(pbr.read_text())["git_version"]
+            except Exception:
+                _package_digest = ""
+    return str(_package_digest)
 
 
 class UnfurlError(Exception):