LibraryOfCongress
Missing Warning on Creating Bag of a Bag
When creating a bag of bag I would expect a warning or confirmation if I really want to create a bag of a bag.
In general it should be possible to create a bag of a bag, but I would not consider it a default case.
Reproduction
bag = bagit.make_bag('/tmp/test_bag', {'Contact-Name': 'Thea'})
This creates a bag with all info, manifest files and the data directory
/tmp/test_bag
| - bag-info.txt
| - bagit.txt
| - data
| - manifest-sha256.txt
| - manifest-sha512.txt
| - tagmanifest-sha256.txt
| - tagmanifest-sha512.txt
If I run make_bag on the same folder again
bag_again = bagit.make_bag('/tmp/test_bag', {'Contact-Name': 'Thea})
this creates a bag with all info, manifest files and the data directory of the first level bag
/tmp/test_bag
| - bag-info.txt
| - bagit.txt
| - data
| - bag-info.txt
| - bagit.txt
| - data
| - manifest-sha256.txt
| - manifest-sha512.txt
| - tagmanifest-sha256.txt
| - tagmanifest-sha512.txt
| - manifest-sha256.txt
| - manifest-sha512.txt
| - tagmanifest-sha256.txt
| - tagmanifest-sha512.txt
Expection
I would expect a warning or even a confirmation, e.g.
>>> bag = bagit.make_bag('/tmp/test_bag', {'Contact-Name': 'Thea'})
>>> bag_again = bagit.make_bag('/tmp/test_bag', {'Contact-Name': 'Thea'})
WARNING: You are creating a bag of a bag. Do you want to continue? [N/y]
Realization
To achieve this behaviour we would need to detect, if a folder is already a bag.
One way could be to use the class constructor of Bag and catch the case for valid bag, but continue on Manifest not found.
Example for the make_bag function:
https://github.com/LibraryOfCongress/bagit-python/blob/master/bagit.py#L141C1-L143C3
def make_bag(
bag_dir, bag_info=None, processes=1, checksums=None, checksum=None, encoding="utf-8"
):
# ....
try:
bagit.Bag(bag_dir)
while True:
ans = input("WARNING: You are creating a bag of a bag. Do you want to continue? [N/y]")
if ans.lower() == 'y':
break
elif not ans or ans.lower() == 'n':
raise UserWarning('Aborted')
except Exception as e:
pass
# ...
I like this as I’ve accidentally made bags within bags when forgetting to add a validate flag! I can’t think of many intentional scenarios where bagging a bag makes sense. Perhaps if this gets approved then there could be also an override flag (like a -y) that will say yes to all baggings of bags in case folks still need that functionality?
Best,
Kieran National Library of Ireland
On Sat 31 May 2025 at 09:40, Thea Tischbein @.***> wrote:
theatischbein created an issue (LibraryOfCongress/bagit-python#186) https://github.com/LibraryOfCongress/bagit-python/issues/186
When creating a bag of bag I would expect a warning or confirmation if I really want to create a bag of a bag.
In general it should be possible to create a bag of a bag, but I would not consider it a default case. Reproduction
bag = bagit.make_bag('/tmp/test_bag', {'Contact-Name': 'Thea'})
This creates a bag with all info, manifest files and the data directory
/tmp/test_bag | - bag-info.txt | - bagit.txt | - data | - manifest-sha256.txt | - manifest-sha512.txt | - tagmanifest-sha256.txt | - tagmanifest-sha512.txt
If I run make_bag on the same folder again
bag_again = bagit.make_bag('/tmp/test_bag', {'Contact-Name': 'Thea})
this creates a bag with all info, manifest files and the data directory of the first level bag
/tmp/test_bag | - bag-info.txt | - bagit.txt | - data | - bag-info.txt | - bagit.txt | - data | - manifest-sha256.txt | - manifest-sha512.txt | - tagmanifest-sha256.txt | - tagmanifest-sha512.txt | - manifest-sha256.txt | - manifest-sha512.txt | - tagmanifest-sha256.txt | - tagmanifest-sha512.txt
Expection
I would expect a warning or even a confirmation, e.g.
bag = bagit.make_bag('/tmp/test_bag', {'Contact-Name': 'Thea'})
bag_again = bagit.make_bag('/tmp/test_bag', {'Contact-Name': 'Thea'}) WARNING: You are creating a bag of a bag. Do you want to continue? [N/y]
Realization
To achieve this behaviour we would need to detect, if a folder is already a bag. One way could be to use the validate function and catch the case for valid or invalid bag, but continue on Manifest not found.
Example for the make_bag function:
https://github.com/LibraryOfCongress/bagit-python/blob/master/bagit.py#L141C1-L143C3
def make_bag( bag_dir, bag_info=None, processes=1, checksums=None, checksum=None, encoding="utf-8" ):
# .... try: bagit.Bag(bag_dir) while True: ans = input("WARNING: You are creating a bag of a bag. Do you want to continue? [N/y]") if ans.lower() == 'y': break elif not ans or ans.lower() == 'n': raise UserWarning('Aborted') except Exception as e: pass # ...— Reply to this email directly, view it on GitHub https://github.com/LibraryOfCongress/bagit-python/issues/186, or unsubscribe https://github.com/notifications/unsubscribe-auth/AAITFPVHGTAKDTBCM2Q5WVL3BFTH7AVCNFSM6AAAAAB6JUUNPCVHI2DSMVQWIX3LMV43ASLTON2WKOZTGEYDKMJWGAZTENQ . You are receiving this because you are subscribed to this thread.Message ID: @.***>
I really like the override flag!
If wanted I could also created a PR, but wanted to discuss it here first.
A second thought: Maybe it is bad to rely on user input. Especially for integration into automated or parallel scripts.
What do you think of
- raising a bagit Error "Directory is already a bag"
- providing a flag for allowing the creating of a bag of bag