Great question! Let’s read the tea leaves:
/AddOns/InstaUp2Date/Resources/installerPackage.py, line 419(rev. 352):

[code]

# try in the cache by displayName and checksum
foundPath = self._findItemInCaches(self.displayName, self.checksumType, self.checksumValue, displayName=self.displayName, additionalSourceFolders=additionalSourceFolders, progressReporter=progressReporter)
if foundPath is not None:
# add the item to the found items
self.addItemToVerifiedFiles(‘%s:%s’ % (self.checksumType, self.checksumValue), foundPath)
if progressReporter is not None:
progressReporter.update(statusMessage=’found by display name or checksum and verified in %s’ % (secondsToReadableTime(time.time() – startTime)))
progressReporter.finishLine()
self.filePath = foundPath
return

workingName = self.displayName

# get an idea of what the name is
if parsedPath.scheme in [‘http’, ‘https’]:
workingName = os.path.basename(parsedPath.path)
else:
workingName = self.source

# look for the item in the caches
if progressReporter is not None:
progressReporter.update(statusMessage=’looking in the source folders by guessed name and checksum’)

# look by guessed name
foundPath = self._findItemInCaches(workingName, self.checksumType, self.checksumValue, displayName=self.displayName, additionalSourceFolders=additionalSourceFolders, progressReporter=progressReporter)
if foundPath is not None:
# add the item to the found items
self.addItemToVerifiedFiles(‘%s:%s’ % (self.checksumType, self.checksumValue), foundPath)
if progressReporter is not None:
progressReporter.update(statusMessage=’found by guessed name and verified in %s’ % (secondsToReadableTime(time.time() – startTime)))
progressReporter.finishLine()
self.filePath = foundPath
return
[/code]

Keep in mind, while I try to figure this out myself, that you don’t need the full path in the catalog file, as long as it’s in one of the two folders InstaUp2Date will look in(/Caches/InstaUp2DateCache and /InstallerFiles/InstaUp2DatePackages, although I try to keep DMG’s in the former and pkg/mpkgs in the latter).

Allister

When InstaUp2Date looks for files it finds them in a number of ways:

1) an absolute path

2) relative to PWD

3) relative to any of the caches

4) by the checksum string in the names in the caches

5) a name guessed from the name/path supplied (could be full paths or URLs)

6) the display name (the human readable name)

7) opens a connection the the http server and grabs the headers to see if there is something there that would give a clue (content-disposition)

8) tries to guess the name from the URL that the connection settles on (may times these things bounce around a bit before finding the final url)

9) finally it will download the item

You happen to be seeing #5 in that path. I recently changed things so that each point is clearer. Before things were a bit more wound through two different methods and confused me at times.