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Reading empty file causes Decode to return error #805

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xyzzyz opened this issue Dec 13, 2021 · 1 comment · May be fixed by #1015
Open

Reading empty file causes Decode to return error #805

xyzzyz opened this issue Dec 13, 2021 · 1 comment · May be fixed by #1015

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@xyzzyz
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xyzzyz commented Dec 13, 2021

In yaml.v3, when reading from empty file, the Decode function returns io.EOF. It should behave just like Unmarshal function, which will happily unmarshal from empty string, without any errors.
costela added a commit to costela/kong-yaml that referenced this issue Jan 14, 2022
@costela
fix: do not error on empty files
93dd765 
this should work around the following go-yaml issue:
go-yaml/yaml#805
costela added a commit to costela/kong-yaml that referenced this issue Jan 14, 2022
@costela
fix: do not error on empty files
7844ea8 
this should work around the following go-yaml issue:
go-yaml/yaml#805
@costela costela mentioned this issue Jan 14, 2022
Merged
alecthomas pushed a commit to alecthomas/kong-yaml that referenced this issue Jan 14, 2022
@costela @alecthomas
fix: do not error on empty files
25e9103 
this should work around the following go-yaml issue:
go-yaml/yaml#805
This was referenced Jan 2, 2023
Closed
Merged
mikelolasagasti added a commit to mikelolasagasti/exporter-toolkit that referenced this issue Jul 23, 2023
@mikelolasagasti
Update to yaml.v3
8a822d2 
Also, modify `empty_config_yml` because with yaml.v3 reading empty file
causes Decode to return EOF error, as described in
go-yaml/yaml#805 issue.
@mikelolasagasti mikelolasagasti mentioned this issue Jul 23, 2023
Open
mikelolasagasti added a commit to mikelolasagasti/exporter-toolkit that referenced this issue Jul 23, 2023
@mikelolasagasti
Update to yaml.v3
f7a824b 
Also, modify `empty_config_yml` because with yaml.v3 reading empty file
causes Decode to return EOF error, as described in
go-yaml/yaml#805 issue.

Signed-off-by: Mikel Olasagasti Uranga <mikel@olasagasti.info>
mikelolasagasti added a commit to mikelolasagasti/exporter-toolkit that referenced this issue Jul 23, 2023
@mikelolasagasti
Update to yaml.v3
d4f4c75 
Also, modify `empty_config_yml` because with yaml.v3 reading empty file
causes Decode to return EOF error, as described in
go-yaml/yaml#805 issue.

Signed-off-by: Mikel Olasagasti Uranga <mikel@olasagasti.info>
@lukemassa
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I originally thought this was a bug as well, and went to try to fix it, but now I believe it might be working as intended.

https://pkg.go.dev/gopkg.in/yaml.v2#Decoder.Decode says

Decode reads the next YAML-encoded value from its input and stores it in the value pointed to by v.

Compare https://pkg.go.dev/gopkg.in/yaml.v3#Unmarshal

Unmarshal decodes the first document found within the in byte slice

Decode reads one document at a time, whereas Unmarshal only reads the first document. Because of this I imagine some clients of Decode() expect to loop until EOF, thus an empty file cannot return nil.

I found this out by trying to do the naive thing and Decode() return nil instead of io.EOF and saw found this code was stuck in an infinite loop: https://github.com/go-yaml/yaml/blob/v3/decode_test.go#L898

Note that the original tests explicitly call out this discrepancy between Decode() and Unmarshal(): https://github.com/go-yaml/yaml/blob/v3/decode_test.go#L852

My view then is to call this out in the documentation (I'll write something up now) and leave the behavior unchanged. Open to other suggestions though.

This was referenced Jan 23, 2024
Open
Merged
mikelolasagasti added a commit to mikelolasagasti/exporter-toolkit that referenced this issue Sep 10, 2024
@mikelolasagasti
Update to yaml.v3
a1826e7 
Also, modify `empty_config_yml` because with yaml.v3 reading empty file
causes Decode to return EOF error, as described in
go-yaml/yaml#805 issue.

Signed-off-by: Mikel Olasagasti Uranga <mikel@olasagasti.info>
mikelolasagasti added a commit to mikelolasagasti/exporter-toolkit that referenced this issue Sep 10, 2024
@mikelolasagasti
Update to yaml.v3
d3e814e 
Also, modify `empty_config_yml` because with yaml.v3 reading empty file
causes Decode to return EOF error, as described in
go-yaml/yaml#805 issue.

Signed-off-by: Mikel Olasagasti Uranga <mikel@olasagasti.info>
@knqyf263 knqyf263 mentioned this issue Nov 20, 2024
Closed
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Clarify the role of io.EOF in Decode lukemassa/yaml
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@xyzzyz @lukemassa