Document.save on create/change only

[aogier]

Checklist

• [x] Tick to sign-off your agreement to the Developer Certificate of Origin (DCO) 1.1
• [x] Added tests for code changes or test/build only changes
• [x] Updated the change log file (CHANGES.md|CHANGELOG.md) or test/build only changes
• [x] Completed the PR template below:

Description

Trivial change that commit to remote db only when creating or actually changing local data.

Current behaviour:

doc = Document(self.db, 'http://example.com')
doc.save()
doc.save()
# doc _rev is now 2-

New behaviour:

doc = Document(self.db, 'http://example.com')
doc.save()
doc.save()
# doc _rev is still 1-

Approach

Implemented a simple boolean check that flip upon Document's dict update methods calls. Document will still be created even if empty, but save will only happen when an actual change is made, minimizing data transfers.

Schema & API Changes

• Document.save only when creating or local copy changed.

Security and Privacy

• "No change"

Testing

• Added new tests:
  • tests.unit.document_tests.test_not_update_unchanged_document

Monitoring and Logging

• "No change"

[aogier]

Ok I think I'm ready for a code review. Tests are passing and all seems promising but I'd definitely like another couple of eyes :)

[aogier]

meh, I forgot setdefault...

[aogier]

added setdefault

[aogier]

I've reintroduced _doc_id logic on some dict methods I'll fix it asap

[aogier]

_document_id logic re-removed from code

[smithsz]

Thanks for all your recent work. It is really appreciated. We’ve discussed this change as a team and feel it’s adding too much complexity to the Document class. I’ve tried a different implementation; instead I compute/compare a hash of the document on each save (here). This change is less invasive but likely a more expensive solution. We’ve decided the library shouldn't offer this feature. If a user is calling .save() multiple times without updating the document then that’s their decision. Thanks again and have a good weekend.

[aogier]

Hi, it seems a good conclusion to me and as a couchdb noob I'll take this design choice as an implementation hint especially on where to put my ctx manager. Thank you for your time and keep up the good work :)

ciao