feat: NewDAGProvider to walk partial DAGs in offline mode

[PsychoPunkSage]

related to issue:kubo#10386 and PR:kubo#10704. Refer this

Problem

• Reprovider strategy currently ignores MFS content
• Each provider implementation has its own DAG traversal logic
• Need a generic way to announce content from any DAG structure

Solution

Added NewDAGProvider that:

• Takes a root CID and traverses its entire DAG
• Uses existing fetcherhelpers.BlockAll for efficient traversal
• Works with any DAG structure (MFS, IPLD, etc.)
• Integrates with existing provider prioritization

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[hsanjuan]

Some comments. Please add some testing as well.

You have utils to generate dags at github.com/ipfs/boxo/ipld/merkledag/test. Verify outCh produces the expected Cids.

[PsychoPunkSage]

Hi @hsanjuan
Did some changes and wrote a test.... BUT Its failing.... Can't seem to get where I'm missing the point

Test Logs

=== RUN   TestNewDAGProvider
    /home/psychopunk_sage/dev/OpenSource/boxo/provider/dagprovider_test.go:163: Created DAG with root QmR1TEGLLewb5Arp6z9QWTzUNgxVvAAJ5vMpnkDQJ9CFiv and 7 expected CIDs
    /home/psychopunk_sage/dev/OpenSource/boxo/provider/dagprovider_test.go:165: Expected CID 1: QmR1TEGLLewb5Arp6z9QWTzUNgxVvAAJ5vMpnkDQJ9CFiv
    /home/psychopunk_sage/dev/OpenSource/boxo/provider/dagprovider_test.go:165: Expected CID 2: QmU5KjgAuvhC79E7jMVBWBg29Aoprdk6jL7qxrXKw1gCTU
    /home/psychopunk_sage/dev/OpenSource/boxo/provider/dagprovider_test.go:165: Expected CID 3: QmYGarcCmpcMYbteSQtrkU6xogQZSFa3d1SqjKq19RR9Qm
    /home/psychopunk_sage/dev/OpenSource/boxo/provider/dagprovider_test.go:165: Expected CID 4: QmNRGfMaSjNcjtyS56JrZBEU5QcGtfViWWG8V9pVqgVpmT
    /home/psychopunk_sage/dev/OpenSource/boxo/provider/dagprovider_test.go:165: Expected CID 5: Qmb28WBcFQ7EPZP38pCLsEhAjxwDDsi14My9LaPNJzVfqu
    /home/psychopunk_sage/dev/OpenSource/boxo/provider/dagprovider_test.go:165: Expected CID 6: QmWiwiH33PJBvTSDS81UnjpzBzdiHhUGWmzrfKPpdbHMy6
    /home/psychopunk_sage/dev/OpenSource/boxo/provider/dagprovider_test.go:165: Expected CID 7: QmTCzUiekoo67MDJqenUXr5ioND7EQ5YjRQzG4ARmVqVzo
2025/02/18 21:56:47 Starting DAG traversal with root: QmR1TEGLLewb5Arp6z9QWTzUNgxVvAAJ5vMpnkDQJ9CFiv
2025/02/18 21:56:47 Starting BlockMatchingOfType
2025/02/18 21:56:47 Processing CID QmR1TEGLLewb5Arp6z9QWTzUNgxVvAAJ5vMpnkDQJ9CFiv (1 processed)
2025/02/18 21:56:47 Added CID to set: QmR1TEGLLewb5Arp6z9QWTzUNgxVvAAJ5vMpnkDQJ9CFiv
2025/02/18 21:56:47 Completed DAG traversal, processed 1 CIDs
2025/02/18 21:56:47 Completed BlockAll traversal
2025/02/18 21:56:47 Sent CID to output: QmR1TEGLLewb5Arp6z9QWTzUNgxVvAAJ5vMpnkDQJ9CFiv
    /home/psychopunk_sage/dev/OpenSource/boxo/provider/dagprovider_test.go:179: Collected CID: QmR1TEGLLewb5Arp6z9QWTzUNgxVvAAJ5vMpnkDQJ9CFiv
    /home/psychopunk_sage/dev/OpenSource/boxo/provider/dagprovider_test.go:183: Collected 1 CIDs
    /home/psychopunk_sage/dev/OpenSource/boxo/provider/dagprovider_test.go:186:
                Error Trace:    /home/psychopunk_sage/dev/OpenSource/boxo/provider/dagprovider_test.go:186
                Error:          Not equal:
                                expected: 7
                                actual  : 1
                Test:           TestNewDAGProvider
                Messages:       number of collected CIDs should match the expected number
--- FAIL: TestNewDAGProvider (0.00s)
FAIL
FAIL    github.com/ipfs/boxo/provider   0.005s

[PsychoPunkSage]

hi @hsanjuan
Can you please review this PR??

[hsanjuan]

Hello, I have fixed your code, which could be done much simpler. I think the work involved for this PR was too complex for you and I suggest you try easier issues first. When I read your code, I wonder if you are using an AI assistant as well to write it, or parts of it at least?

@gammazero Can you have a look, since reviewing would be mostly reviewing myself.

i fixed it

[lidel]

• This and Add MFS Support to Reprovider Strategy kubo#10704 needs both be rebased due to buffered provider added in provider: add a buffered KeyChanFunc. #870