Merge pull request #562 from vmarkovtsev/patch-4

Gracefully handle missing astropy in _open_impl
asdf-format · Oct 16, 2018 · 4976a59 · 4976a59
2 parents fc51e24 + f95deb8
commit 4976a59
Show file tree

Hide file tree

Showing 2 changed files with 11 additions and 4 deletions.
diff --git a/CHANGES.rst b/CHANGES.rst
@@ -19,6 +19,9 @@
 - Fix bug that caused subclass of external type to be serialized by the wrong
   tag. [#560]
 
+- Fix bug that occurred when attempting to open invalid file but Astropy import
+  fails while checking for ASDF-in-FITS. [#562]
+
 2.1.0 (2018-09-25)
 ------------------
 

diff --git a/asdf/asdf.py b/asdf/asdf.py
@@ -681,10 +681,14 @@ def _open_impl(cls, self, fd, uri=None, mode='r',
                             ignore_missing_extensions=ignore_missing_extensions,
                             _extension_metadata=self._extension_metadata)
             except ValueError:
-                pass
-            raise ValueError(
-                "Input object does not appear to be ASDF file or FITS with " +
-                "ASDF extension")
+                raise ValueError(
+                    "Input object does not appear to be an ASDF file or a FITS with " +
+                    "ASDF extension") from None
+            except ImportError:
+                raise ValueError(
+                    "Input object does not appear to be an ASDF file. Cannot check " +
+                    "if it is a FITS with ASDF extension because 'astropy' is not " +
+                    "installed") from None
         return cls._open_asdf(self, fd, uri=uri, mode=mode,
                 validate_checksums=validate_checksums,
                 do_not_fill_defaults=do_not_fill_defaults,