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encoding/csv: documentation of UseCRLF is incomplete #47774

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rs-blade opened this issue Aug 18, 2021 · 3 comments
Open

encoding/csv: documentation of UseCRLF is incomplete #47774

rs-blade opened this issue Aug 18, 2021 · 3 comments
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Documentation NeedsInvestigation Someone must examine and confirm this is a valid issue and not a duplicate of an existing one.
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@rs-blade
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According to the documentation of the UseCRLF flag here:

go/src/encoding/csv/writer.go

Line 23 in 946e254

// If UseCRLF is true, the Writer ends each output line with \r\n instead of \n.

it only influences the line terminator. When looking at the code one can see that setting that flag to true also impacts the output of the cell content: \r is removed and \n replaced by \r\n.
This behavior should also be reflected in the documentation!
@seankhliao
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csv doesn't escape newlines in cell contents, so if there's a newline in a cell it is also the end of an output line.

"hello", "foo\nbar", "world"
as csv would be

hello,"foo
bar",world

@rs-blade
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You're right. What I meant when writing \r and \n was the characters 13 and 10.
So to be clear: If UseCRLF is true a string of chars 0x41 0x0d 0x42 will become 0x22 0x41 0x42 0x22. So a quoted string where the 0x0d is removed (see here:

go/src/encoding/csv/writer.go

Line 89 in 8b471db

case '"':
)
On the other hand 0x41 0x0a 0x42 becomes 0x22 0x41 0x0d 0x0a 0x42 0x22 (see here:

go/src/encoding/csv/writer.go

Line 97 in 8b471db

_, err = w.w.WriteString("\r\n")
)

I think this is important to know, so the documentation should tell you about that behavior.

@mknyszek mknyszek changed the title Documentation of UseCRLF in encoding/csv/writer is incomplete encoding/csv: documentation of UseCRLF is incomplete Aug 18, 2021
@mknyszek mknyszek added the NeedsInvestigation Someone must examine and confirm this is a valid issue and not a duplicate of an existing one. label Aug 18, 2021
@mknyszek mknyszek added this to the Backlog milestone Aug 18, 2021
@seankhliao
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I understood that part, I'm saying that because it's not escaped in csv, an output line != single record and it changes all output line endings, not just end of record endings.
But feel free to send a PR/CL with what you think would make it clearer

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@mknyszek @rs-blade @gopherbot @seankhliao