feat: ResultBytes #86
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- Add ResultBytes to sqlitex to support one-result BLOB queries - Export ErrNoResults/ErrMultipleResults so the user can react to these conditions programmatically.
| var ( | ||
| ErrNoResults = errors.New("sqlite: statement has no results") | ||
| ErrMultipleResults = errors.New("sqlite: statement has multiple result rows") | ||
| ) |
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Can I get some clarification on this? Generally, I believe that sentinel errors should be exported if they have meaningful names and convey meaningful information. In this case, they would allow the caller the option to distinguish between "the call I explicitly expected to have one result has none" and " the call I explicitly expected to have one result has more than one".
If the argument is that you deliberately want this information to be opaque, I can get behind that I suppose. The semantics of the methods that might return these errors are clear enough ("one result, or error"). That would make these errors not so much sentinel errors but helpful templates. I just want to make sure I'm clear on the reasoning behind the decision to hide this distinction.
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Yup, sorry for being terse. I'm asking to revert from the standpoint that ResultBytes is useful on its own (and the title/focus of the PR) and I would like to merge it in. I am less sure about exporting the errors at this time, so would like to figure that outside the scope of this PR.
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| // ResultBytes reads the first column of the first and only row produced by running stmt into buf, returning the number of bytes read. | ||
| // It returns an error if there is not exactly one result row. | ||
| func ResultBytes(stmt *sqlite.Stmt, buf []byte) (int, error) { |
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Mind adding a line in the CHANGELOG for this new function? (See surrounding entries for format and please link to this PR.)
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Oh, and mind adding a small test for this function? |
conditions programmatically.
(ref: Document pattern of checking for zero rows #85)