added related fields into the search capability consistently in all DB

[Nightwing-77]

In the current database search, related fields were not being considered because they were pre-filtered in the get_searchable_search_fields function.

To address this:

I switched to using the get_search_fields function, which returns all fields.

Flattened the field tree and converted related fields into a combined format.
Example: related field (author) { search field (name) } becomes searchfield(author__name).

The original get_search_field function was intended for tree traversal, but it only returned a flattened tree with filtered search fields, so I simplified the logic.

Now, the search vector is constructed using SearchVector(author__name).

While building the search vector, annotations are filtered out, and only the actual field names are used.

[gasman]

@Nightwing-77 It looks like this PR incorporates changes from a previous version of #68 - please can you rebase this on current main?

I'm also not clear on what exactly this PR is fixing. If this is indeed making Book.objects.search("tolkien", fields=["author__name"]) work across all backends, then there needs to be a test covering that, not just the get_search_field part. However, I'm under the impression that that would be a much bigger task, since on at least Sqlite (and possibly other DB backends? I'm not clear), the fields parameter doesn't work at all, even for local fields, as per #47.

For context - the test_get_search_field_for_related_fields tests were added in 49b0ee1 in response to me finding the code in get_search_field that was apparently written in anticipation of future fields=["author__name"] support, but was broken (due to get_searchable_search_fields not containing RelatedFields records). Fixing this is a necessary step towards supporting fields=["author__name"], but not the only one.

[Nightwing-77]

@Nightwing-77 It looks like this PR incorporates changes from a previous version of #68 - please can you rebase this on current main?

I'm also not clear on what exactly this PR is fixing. If this is indeed making Book.objects.search("tolkien", fields=["author__name"]) work across all backends, then there needs to be a test covering that, not just the get_search_field part. However, I'm under the impression that that would be a much bigger task, since on at least Sqlite (and possibly other DB backends? I'm not clear), the fields parameter doesn't work at all, even for local fields, as per #47.

For context - the test_get_search_field_for_related_fields tests were added in 49b0ee1 in response to me finding the code in get_search_field that was apparently written in anticipation of future fields=["author__name"] support, but was broken (due to get_searchable_search_fields not containing RelatedFields records). Fixing this is a necessary step towards supporting fields=["author__name"], but not the only one.

hey! sure i'll rebase it!! also i'm very confident the functionality of .search is working on db backend !! i don't exactly remember where but i think i did face that issue and fix it!! maybe in #68 (it's been some time , i don't remember rt now) : could u go and check out the test case in test_postgres_backend.py‎

[Nightwing-77]

@gasman i've added the proper test case and was able to get the testcases to pass for postgresql , i'm not sure why it kept failing for other two!!