Added commands for working with the plugin cache. (#12576)

# Description
This pull request provides three new commands:
`polars store-ls` - moved from `polars ls`. It provides the list of all
object stored in the plugin cache
`polars store-rm` - deletes a cached object
`polars store-get` - gets an object from the cache. 

The addition of `polars store-get` required adding a reference_count to
cached entries. `polars get` is the only command that will increment
this value. `polars rm` will remove the value despite it's count. Calls
to PolarsPlugin::custom_value_dropped will decrement the value.

The prefix store- was chosen due to there already being a `polars cache`
command. These commands were not made sub-commands as there isn't a way
to display help for sub commands in plugins (e.g. `polars store`
displaying help) and I felt the store- seemed fine anyways.

The output of `polars store-ls` now shows the reference count for each
object.

# User-Facing Changes
polars ls has now moved to polars store-ls

---------

Co-authored-by: Jack Wright <jack.wright@disqo.com>

crates/nu_plugin_polars/src/dataframe/eager/list.rs

@@ -1,123 +0,0 @@
-use nu_plugin::{EngineInterface, EvaluatedCall, PluginCommand};
-use nu_protocol::{
-    record, Category, Example, IntoPipelineData, LabeledError, PipelineData, Signature, Value,
-};
-
-use crate::{values::PolarsPluginObject, PolarsPlugin};
-
-#[derive(Clone)]
-pub struct ListDF;
-
-impl PluginCommand for ListDF {
-    type Plugin = PolarsPlugin;
-
-    fn name(&self) -> &str {
-        "polars ls"
-    }
-
-    fn usage(&self) -> &str {
-        "Lists stored dataframes."
-    }
-
-    fn signature(&self) -> Signature {
-        Signature::build(self.name()).category(Category::Custom("dataframe".into()))
-    }
-
-    fn examples(&self) -> Vec<Example> {
-        vec![Example {
-            description: "Creates a new dataframe and shows it in the dataframe list",
-            example: r#"let test = ([[a b];[1 2] [3 4]] | dfr into-df);
-    polars ls"#,
-            result: None,
-        }]
-    }
-
-    fn run(
-        &self,
-        plugin: &Self::Plugin,
-        engine: &EngineInterface,
-        call: &EvaluatedCall,
-        _input: PipelineData,
-    ) -> Result<PipelineData, LabeledError> {
-        let vals = plugin.cache.process_entries(|(key, value)| {
-            let span_contents = engine.get_span_contents(value.span)?;
-            let span_contents = String::from_utf8_lossy(&span_contents);
-            match &value.value {
-                PolarsPluginObject::NuDataFrame(df) => Ok(Some(Value::record(
-                    record! {
-                        "key" => Value::string(key.to_string(), call.head),
-                        "created" => Value::date(value.created, call.head),
-                        "columns" => Value::int(df.as_ref().width() as i64, call.head),
-                        "rows" => Value::int(df.as_ref().height() as i64, call.head),
-                        "type" => Value::string("NuDataFrame", call.head),
-                        "estimated_size" => Value::filesize(df.to_polars().estimated_size() as i64, call.head),
-                        "span_contents" =>  Value::string(span_contents, value.span),
-                        "span_start" => Value::int(value.span.start as i64, call.head),
-                        "span_end" => Value::int(value.span.end as i64, call.head),
-                    },
-                    call.head,
-                ))),
-                PolarsPluginObject::NuLazyFrame(lf) => {
-                    let lf = lf.clone().collect(call.head)?;
-                    Ok(Some(Value::record(
-                        record! {
-                            "key" => Value::string(key.to_string(), call.head),
-                            "created" => Value::date(value.created, call.head),
-                            "columns" => Value::int(lf.as_ref().width() as i64, call.head),
-                            "rows" => Value::int(lf.as_ref().height() as i64, call.head),
-                            "type" => Value::string("NuLazyFrame", call.head),
-                            "estimated_size" => Value::filesize(lf.to_polars().estimated_size() as i64, call.head),
-                            "span_contents" =>  Value::string(span_contents, value.span),
-                            "span_start" => Value::int(value.span.start as i64, call.head),
-                            "span_end" => Value::int(value.span.end as i64, call.head),
-                        },
-                        call.head,
-                    )))
-                }
-                PolarsPluginObject::NuExpression(_) => Ok(Some(Value::record(
-                    record! {
-                        "key" => Value::string(key.to_string(), call.head),
-                        "created" => Value::date(value.created, call.head),
-                        "columns" => Value::nothing(call.head),
-                        "rows" => Value::nothing(call.head),
-                        "type" => Value::string("NuExpression", call.head),
-                        "estimated_size" => Value::nothing(call.head),
-                        "span_contents" =>  Value::string(span_contents, value.span),
-                        "span_start" => Value::int(value.span.start as i64, call.head),
-                        "span_end" => Value::int(value.span.end as i64, call.head),
-                    },
-                    call.head,
-                ))),
-                PolarsPluginObject::NuLazyGroupBy(_) => Ok(Some(Value::record(
-                    record! {
-                        "key" => Value::string(key.to_string(), call.head),
-                        "columns" => Value::nothing(call.head),
-                        "rows" => Value::nothing(call.head),
-                        "type" => Value::string("NuLazyGroupBy", call.head),
-                        "estimated_size" => Value::nothing(call.head),
-                        "span_contents" =>  Value::string(span_contents, call.head),
-                        "span_start" => Value::int(call.head.start as i64, call.head),
-                        "span_end" => Value::int(call.head.end as i64, call.head),
-                    },
-                    call.head,
-                ))),
-                PolarsPluginObject::NuWhen(_) => Ok(Some(Value::record(
-                    record! {
-                        "key" => Value::string(key.to_string(), call.head),
-                        "columns" => Value::nothing(call.head),
-                        "rows" => Value::nothing(call.head),
-                        "type" => Value::string("NuWhen", call.head),
-                        "estimated_size" => Value::nothing(call.head),
-                        "span_contents" =>  Value::string(span_contents.to_string(), call.head),
-                        "span_start" => Value::int(call.head.start as i64, call.head),
-                        "span_end" => Value::int(call.head.end as i64, call.head),
-                    },
-                    call.head,
-                ))),
-            }
-        })?;
-        let vals = vals.into_iter().flatten().collect();
-        let list = Value::list(vals, call.head);
-        Ok(list.into_pipeline_data())
-    }
-}

crates/nu_plugin_polars/src/dataframe/eager/mod.rs

@@ -9,7 +9,6 @@ mod filter_with;
 mod first;
 mod get;
 mod last;
-mod list;
 mod melt;
 mod open;
 mod query_df;
@@ -45,7 +44,6 @@ pub use filter_with::FilterWith;
 pub use first::FirstDF;
 pub use get::GetDF;
 pub use last::LastDF;
-pub use list::ListDF;
 pub use melt::MeltDF;
 use nu_plugin::PluginCommand;
 pub use query_df::QueryDf;
@@ -82,7 +80,6 @@ pub(crate) fn eager_commands() -> Vec<Box<dyn PluginCommand<Plugin = PolarsPlugi
         Box::new(Summary),
         Box::new(FirstDF),
         Box::new(LastDF),
-        Box::new(ListDF),
         Box::new(RenameDF),
         Box::new(SampleDF),
         Box::new(ShapeDF),

crates/nu_plugin_polars/src/dataframe/series/date/as_datetime.rs

@@ -186,10 +186,11 @@ fn command(
 #[cfg(test)]
 mod test {
     use super::*;
-    use crate::test::test_polars_plugin_command;
+    use crate::test::test_polars_plugin_command_with_decls;
+    use nu_command::IntoDatetime;
 
     #[test]
     fn test_examples() -> Result<(), ShellError> {
-        test_polars_plugin_command(&AsDateTime)
+        test_polars_plugin_command_with_decls(&AsDateTime, vec![Box::new(IntoDatetime)])
     }
 }

crates/nu_plugin_polars/src/dataframe/series/date/get_day.rs

@@ -93,10 +93,11 @@ fn command(
 #[cfg(test)]
 mod test {
     use super::*;
-    use crate::test::test_polars_plugin_command;
+    use crate::test::test_polars_plugin_command_with_decls;
+    use nu_command::IntoDatetime;
 
     #[test]
     fn test_examples() -> Result<(), ShellError> {
-        test_polars_plugin_command(&GetDay)
+        test_polars_plugin_command_with_decls(&GetDay, vec![Box::new(IntoDatetime)])
     }
 }

crates/nu_plugin_polars/src/dataframe/series/date/get_hour.rs

@@ -85,10 +85,11 @@ fn command(
 #[cfg(test)]
 mod test {
     use super::*;
-    use crate::test::test_polars_plugin_command;
+    use crate::test::test_polars_plugin_command_with_decls;
+    use nu_command::IntoDatetime;
 
     #[test]
     fn test_examples() -> Result<(), ShellError> {
-        test_polars_plugin_command(&GetHour)
+        test_polars_plugin_command_with_decls(&GetHour, vec![Box::new(IntoDatetime)])
     }
 }

crates/nu_plugin_polars/src/dataframe/series/date/get_minute.rs

@@ -83,10 +83,11 @@ fn command(
 #[cfg(test)]
 mod test {
     use super::*;
-    use crate::test::test_polars_plugin_command;
+    use crate::test::test_polars_plugin_command_with_decls;
+    use nu_command::IntoDatetime;
 
     #[test]
     fn test_examples() -> Result<(), ShellError> {
-        test_polars_plugin_command(&GetMinute)
+        test_polars_plugin_command_with_decls(&GetMinute, vec![Box::new(IntoDatetime)])
     }
 }

crates/nu_plugin_polars/src/dataframe/series/date/get_month.rs

@@ -85,10 +85,11 @@ fn command(
 #[cfg(test)]
 mod test {
     use super::*;
-    use crate::test::test_polars_plugin_command;
+    use crate::test::test_polars_plugin_command_with_decls;
+    use nu_command::IntoDatetime;
 
     #[test]
     fn test_examples() -> Result<(), ShellError> {
-        test_polars_plugin_command(&GetMonth)
+        test_polars_plugin_command_with_decls(&GetMonth, vec![Box::new(IntoDatetime)])
     }
 }

crates/nu_plugin_polars/src/dataframe/series/date/get_nanosecond.rs

@@ -85,10 +85,11 @@ fn command(
 #[cfg(test)]
 mod test {
     use super::*;
-    use crate::test::test_polars_plugin_command;
+    use crate::test::test_polars_plugin_command_with_decls;
+    use nu_command::IntoDatetime;
 
     #[test]
     fn test_examples() -> Result<(), ShellError> {
-        test_polars_plugin_command(&GetNanosecond)
+        test_polars_plugin_command_with_decls(&GetNanosecond, vec![Box::new(IntoDatetime)])
     }
 }

crates/nu_plugin_polars/src/dataframe/series/date/get_ordinal.rs

@@ -85,10 +85,11 @@ fn command(
 #[cfg(test)]
 mod test {
     use super::*;
-    use crate::test::test_polars_plugin_command;
+    use crate::test::test_polars_plugin_command_with_decls;
+    use nu_command::IntoDatetime;
 
     #[test]
     fn test_examples() -> Result<(), ShellError> {
-        test_polars_plugin_command(&GetOrdinal)
+        test_polars_plugin_command_with_decls(&GetOrdinal, vec![Box::new(IntoDatetime)])
     }
 }

crates/nu_plugin_polars/src/dataframe/series/date/get_second.rs

@@ -85,10 +85,11 @@ fn command(
 #[cfg(test)]
 mod test {
     use super::*;
-    use crate::test::test_polars_plugin_command;
+    use crate::test::test_polars_plugin_command_with_decls;
+    use nu_command::IntoDatetime;
 
     #[test]
     fn test_examples() -> Result<(), ShellError> {
-        test_polars_plugin_command(&GetSecond)
+        test_polars_plugin_command_with_decls(&GetSecond, vec![Box::new(IntoDatetime)])
     }
 }

crates/nu_plugin_polars/src/dataframe/series/date/get_week.rs

@@ -85,10 +85,11 @@ fn command(
 #[cfg(test)]
 mod test {
     use super::*;
-    use crate::test::test_polars_plugin_command;
+    use crate::test::test_polars_plugin_command_with_decls;
+    use nu_command::IntoDatetime;
 
     #[test]
     fn test_examples() -> Result<(), ShellError> {
-        test_polars_plugin_command(&GetWeek)
+        test_polars_plugin_command_with_decls(&GetWeek, vec![Box::new(IntoDatetime)])
     }
 }

crates/nu_plugin_polars/src/dataframe/series/date/get_weekday.rs

@@ -85,10 +85,11 @@ fn command(
 #[cfg(test)]
 mod test {
     use super::*;
-    use crate::test::test_polars_plugin_command;
+    use crate::test::test_polars_plugin_command_with_decls;
+    use nu_command::IntoDatetime;
 
     #[test]
     fn test_examples() -> Result<(), ShellError> {
-        test_polars_plugin_command(&GetWeekDay)
+        test_polars_plugin_command_with_decls(&GetWeekDay, vec![Box::new(IntoDatetime)])
     }
 }

crates/nu_plugin_polars/src/dataframe/series/date/get_year.rs

@@ -85,10 +85,11 @@ fn command(
 #[cfg(test)]
 mod test {
     use super::*;
-    use crate::test::test_polars_plugin_command;
+    use crate::test::test_polars_plugin_command_with_decls;
+    use nu_command::IntoDatetime;
 
     #[test]
     fn test_examples() -> Result<(), ShellError> {
-        test_polars_plugin_command(&GetYear)
+        test_polars_plugin_command_with_decls(&GetYear, vec![Box::new(IntoDatetime)])
     }
 }

crates/nu_plugin_polars/src/dataframe/series/string/strftime.rs

@@ -104,10 +104,11 @@ fn command(
 #[cfg(test)]
 mod test {
     use super::*;
-    use crate::test::test_polars_plugin_command;
+    use crate::test::test_polars_plugin_command_with_decls;
+    use nu_command::IntoDatetime;
 
     #[test]
     fn test_examples() -> Result<(), ShellError> {
-        test_polars_plugin_command(&StrFTime)
+        test_polars_plugin_command_with_decls(&StrFTime, vec![Box::new(IntoDatetime)])
     }
 }

crates/nu_plugin_polars/src/dataframe/values/mod.rs

@@ -107,6 +107,16 @@ impl PolarsPluginObject {
             PolarsPluginObject::NuWhen(w) => w.id,
         }
     }
+
+    pub fn into_value(self, span: Span) -> Value {
+        match self {
+            PolarsPluginObject::NuDataFrame(df) => df.into_value(span),
+            PolarsPluginObject::NuLazyFrame(lf) => lf.into_value(span),
+            PolarsPluginObject::NuExpression(e) => e.into_value(span),
+            PolarsPluginObject::NuLazyGroupBy(lg) => lg.into_value(span),
+            PolarsPluginObject::NuWhen(w) => w.into_value(span),
+        }
+    }
 }
 
 #[derive(Debug, Clone)]