Empty list into object could be inligned

[finistseb]

Hello, we use descriptor in ovhdata-cli (open sourced recently),
The display of nested empty list can be confusing.

For example, this given struct

    fn create_metadata_error() -> TableMeta {
        TableMeta {
            table_name: Some("table-name".to_string()),
            status: "ERROR".to_string(),
            error: Some("Metadata were not extracted".to_string()),
            error_code: Some("404".to_string()),
            started_at: None,
            ended_at: None,
            metadata: Vec::new(),
        }
    }

Will produce the output :

Table Name: table-name
Status:     ERROR
Error:      Metadata were not extracted
Error Code: 404
Started At: ~
Ended At:   ~
Metadata:
Empty list

Empty list is interesting for display empty tables likes that:

NAME   TYPE   CARDINALITY   MIN   MAX
Empty list

But, IMO, nested list could be displayed likes that

Table Name: table-name
Status:     ERROR
Error:      Metadata were not extracted
Error Code: 404
Started At: ~
Ended At:   ~
Metadata: [~]

This library have not commit since 2 years, is this repo still maintained?
Thanks,
Sebastien

[XciD]

Hi Sebatien,

Can you give me the struct definition ?

Vec<> have two way for output:

• without option: should return ~
  

  descriptor/src/lib.rs

  Line 632 in f2604ab

  ctx.write_value(writer, "~".to_string())

• with #[descriptor(output_table)], should return Empty List
  

  descriptor/src/lib.rs

  Line 781 in f2604ab

  writeln!(writer, "Empty list")?;

[finistseb]

Hi Adrien,
Thanks for your quick reply

Here is the struct definition

#[derive(Debug, Clone, Deserialize, Serialize, Descriptor)]
#[serde(rename_all = "camelCase")]
pub struct TableMeta {
    pub table_name: Option<String>,
    pub status: String,
    pub error: Option<String>,
    pub error_code: Option<String>,
    #[descriptor(into = OptionDescribedDateTime)]
    pub started_at: Option<DateTime<Utc>>,
    #[descriptor(into = OptionDescribedDateTime)]
    pub ended_at: Option<DateTime<Utc>>,
    #[descriptor(output_table)]
    #[serde(default, skip_serializing_if = "Vec::is_empty")]
    pub metadata: Vec<Metadata>,
}

#[derive(Debug, Clone, Deserialize, Serialize, Descriptor)]
#[serde(rename_all = "camelCase")]
pub struct Metadata {
    pub name: String,
    #[serde(rename = "type")]
    #[descriptor(rename_header = "TYPE")]
    pub type_name: String,
    pub cardinality: i64,
    pub min: i64,
    pub max: i64,
}

This test gives this output

        let describe_metadata = TableMeta {
            table_name: Some("table-name".to_string()),
            status: "PROCESSING".to_string(),
            error: None,
            error_code: None,
            started_at: Some(datetime_micro(2021, 6, 3, 12, 22, 46, 107055)),
            ended_at: None,
            metadata: Vec::new(),
        };
        
        let describe = object_describe_to_string(&describe_metadata).unwrap();

OUTPUT

Table Name: table-name
Status:     PROCESSING
Error:      ~
Error Code: ~
Started At: 03-06-21 12:22:46
Ended At:   ~
Metadata:
Empty list

[XciD]

Try to remove the #[descriptor(output_table)]

[finistseb]

In this case, the output is not smart

Table Name: table-name
Status:     SUCCESS
Error:      ~
Error Code: ~
Started At: 03-06-21 12:22:46
Ended At:   03-06-21 12:24:46
Metadata:
- Name:        id
  Type Name:   num
  Cardinality: 788
  Min:         0
  Max:         788
- Name:        some_column
  Type Name:   txt
  Cardinality: 580
  Min:         0
  Max:         911

[XciD]

Very specific use case. will check how I can do that