Panic reduction

[orpheuslummis]

A tracking issue for minimizing panic.

The risk with panic() is that it leads to runtime crash.

Acceptable kinds of panic:

• In initialization as they are ran as part of process startup (AFAIK) and not expected to induce runtime crashes.
• When intentional, internal, and handled by recover()
• Crash intentionally when facing some kinds of "exceptional situations"

Paths forward:

• convert to error
• avoid situation

Here are the current points calling panic() (as of commit 16084c8 ...), excluding tests.
I'm marking each as a task that can be marked off with a decision/change.

• defradb/client/document.go

  Line 397 in 16084c8

  panic(err) //should we return (string, error)?

  and

  defradb/client/document.go

  Line 402 in 16084c8

  panic(err) // same as above

• defradb/db/db.go

  Line 224 in 16084c8

  panic(err)

• defradb/db/container/container.go

  Line 43 in 16084c8

  panic("Invalid index for document container")

• defradb/db/container/container.go

  Line 67 in 16084c8

  panic("Invalid index for Document container")

• defradb/net/utils/util.go

  Line 31 in 16084c8

  panic("coudn't parse default bootstrap peers")

• defradb/core/data.go

  Line 54 in 16084c8

  panic("not implemented") // TODO: Implement

  (although it is a marked as TODO)

• defradb/core/data.go

  Line 59 in 16084c8

  panic("not implemented") // TODO: Implement

  (although it is a marked as TODO)

• defradb/logging/logger.go

  Line 35 in 16084c8

  panic(err)

  (might be idiomatic to panic like this, indicated by the use of must)

• defradb/core/net/protocol.go

  Line 42 in 16084c8

  panic(err)

  (as part of init so IMO is fine)

• defradb/merkle/crdt/composite.go

  Line 51 in 16084c8

  panic(err)

  (part of init)

• defradb/merkle/crdt/lwwreg.go

  Line 47 in 16084c8

  panic(err)

  (part of init)

[AndrewSisley]

Defering panics in client/document as the correct behaviour requires a public function signature change (to return the error), and IMO that is not suitable for a patch release (v0.x.y or not).

[AndrewSisley]

Moved to v0.4.0 as remaining items require pub signature changes