handle case where file contents change but resource name does not (e.g. if resource maintainer uses same name for each new version of a package)

lib/spack/spack/fetch_strategy.py

@@ -107,6 +107,8 @@ def reset(self):   pass  # Revert to freshly downloaded state.
 
     def archive(self, destination): pass  # Used to create tarball for mirror.
 
+    def file_hash(self): pass # Identifies the resource to be retrieved
+
     def __str__(self):  # Should be human readable URL.
         return "FetchStrategy.__str___"
 
@@ -217,6 +219,10 @@ def archive_file(self):
         """Path to the source archive within this stage directory."""
         return self.stage.archive_file
 
+    @property
+    def file_hash(self):
+        return self.digest
+
     @_needs_stage
     def expand(self):
         if not self.expand_archive:
@@ -349,6 +355,10 @@ def archive(self, destination, **kwargs):
         self.stage.chdir()
         tar('-czf', destination, os.path.basename(self.stage.source_path))
 
+    @property
+    def file_hash(self):
+        return None
+
     def __str__(self):
         return "VCS: %s" % self.url
 

lib/spack/spack/mirror.py

@@ -61,7 +61,10 @@ def mirror_archive_filename(spec, fetcher):
         # Otherwise we'll make a .tar.gz ourselves
         ext = 'tar.gz'
 
-    filename = "%s-%s" % (spec.package.name, spec.version)
+    tokens = [spec.package.name, spec.version]
+    if fetcher.file_hash:
+        tokens.append(fetcher.file_hash)
+    filename = '-'.join(str(t) for t in tokens)
     if ext:
         filename += ".%s" % ext
     return filename