Feature url build_query accepts records with lists of strings (#14073)

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# Description

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Swagger supports lists (a.k.a arrays) in query parameters:

https://swagger.io/docs/specification/v3_0/serialization/
It supports three different styles:
- explode=true
- spaceDelimited
- pipeDelimited
With explode=true being the default and hence most common. It is the
hardest to use inside of nushell, as the others are just a `string join`
away. This commit adds lists with the explode=true format.

# User-Facing Changes
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Before:

: {a[]: [one two three], b: four} | url build-query
Error: nu:🐚:unsupported_input
× Unsupported input
╭─[entry #33:1:1]
1 │ {a[]: [one two three], b: four} | url build-query
· ───────────────┬─────────────── ───────┬───────
· │ ╰── Expected a record with string values
· ╰── value originates from here
       ╰────

After:

: {a[]: [one two three], b: four} | url build-query
    a%5B%5D=one&a%5B%5D=two&a%5B%5D=three&b=four


Despite reading CONTRIBUTING.md I didn't get approval before making the
change. My judgment is that this doesn't qualify as being "change
something significantly".

# Tests + Formatting

I added the Example instance for the automatic tests. I couldn't figure
out how to add an Example for the error case, so I did that with manual
testing. E.g.:

: {a[]: [one two [three]], b: four} | url build-query

Error: nu:🐚:unsupported_input


× Unsupported input

╭─[entry #3:1:1]

1 │ {a[]: [one two [three]], b: four} | url build-query

· ────────────────┬──────────────── ───────┬───────

· │ ╰── Expected a record with list of string values

· ╰── value originates from here

       ╰────

: {a[]: [one two 3hr], b: four} | url build-query

Error: nu:🐚:unsupported_input


× Unsupported input

╭─[entry #4:1:1]

1 │ {a[]: [one two 3hr], b: four} | url build-query

· ──────────────┬────────────── ───────┬───────

· │ ╰── Expected a record with list of string values

· ╰── value originates from here

       ╰──── 
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I ran the four cargo commands on my local machine. I had to run the
tests with:

LANG=C and -j 1 and even then I got one failure:

thread 'commands::umkdir::mkdir_umask_permission' panicked at
crates/nu-command/tests/commands/umkdir.rs:148:9:
assertion `left == right` failed: Most *nix systems have 0o00022 as the
umask. So directory permission should be 0o40755 = 0o
40777 & (!0o00022)
left: 16893
    right: 16877

but this isn't related to this change (I seem to not be running most
*nix system; and don't have a lot of RAM for the number of cores). The
other three cargo commands didn't have errors or warnings.

# After Submitting
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I will add the new example to [the
documentation](https://github.com/nushell/nushell.github.io).

# Open questions / possible future work

Things I noticed, and would like to mention and am open to adding, but
don't think I am deep enough in nushell to do them pro-actively.

## Add an argument for the other query parameter list styles

I don't know how frequent they are and I currently don't need them, so
following KISS I didn't add them.

## long input_span marked

In e.g.:

: {a[]: [one two 3hr], b: four} | url build-query

Error: nu:🐚:unsupported_input


× Unsupported input

╭─[entry #4:1:1]

1 │ {a[]: [one two 3hr], b: four} | url build-query

· ──────────────┬────────────── ───────┬───────

· │ ╰── Expected a record with list of string values

· ╰── value originates from here

       ╰──── 

the entire record is marked as input_span instead of just the "3hr" that
is causing the problem. Changing that would be trivial, but I'm not deep
enough into nushell to understand all the consequences of changing that.


## Error message says string values despite accepting numbers etc.

The error message said it only accepted strings despite accepting
numbers etc. (anything it can coerce into string). I couldn't find a
good wording myself and that was how it was before. I simply added a
"list of strings".

crates/nu-command/src/network/url/build_query.rs

@@ -42,6 +42,11 @@ impl Command for SubCommand {
                 example: r#"{a:"AT&T", b: "AT T"} | url build-query"#,
                 result: Some(Value::test_string("a=AT%26T&b=AT+T")),
             },
+            Example {
+                description: "Outputs a query string representing the contents of this record",
+                example: r#"{a: ["one", "two"], b: "three"} | url build-query"#,
+                result: Some(Value::test_string("a=one&a=two&b=three")),
+            },
         ]
     }
 
@@ -66,30 +71,44 @@ fn to_url(input: PipelineData, head: Span) -> Result<PipelineData, ShellError> {
                 Value::Record { ref val, .. } => {
                     let mut row_vec = vec![];
                     for (k, v) in &**val {
-                        match v.coerce_string() {
-                            Ok(s) => {
-                                row_vec.push((k.clone(), s));
-                            }
-                            _ => {
-                                return Err(ShellError::UnsupportedInput {
-                                    msg: "Expected a record with string values".to_string(),
-                                    input: "value originates from here".into(),
-                                    msg_span: head,
-                                    input_span: span,
-                                });
+                        match v {
+                            Value::List { ref vals, .. } => {
+                                for v_item in vals {
+                                    row_vec.push((
+                                        k.clone(),
+                                        v_item.coerce_string().map_err(|_| {
+                                            ShellError::UnsupportedInput {
+                                                msg: "Expected a record with list of string values"
+                                                    .to_string(),
+                                                input: "value originates from here".into(),
+                                                msg_span: head,
+                                                input_span: span,
+                                            }
+                                        })?,
+                                    ));
+                                }
                             }
+                            _ => row_vec.push((
+                                k.clone(),
+                                v.coerce_string()
+                                    .map_err(|_| ShellError::UnsupportedInput {
+                                        msg:
+                                            "Expected a record with string or list of string values"
+                                                .to_string(),
+                                        input: "value originates from here".into(),
+                                        msg_span: head,
+                                        input_span: span,
+                                    })?,
+                            )),
                         }
                     }
 
-                    match serde_urlencoded::to_string(row_vec) {
-                        Ok(s) => Ok(s),
-                        _ => Err(ShellError::CantConvert {
-                            to_type: "URL".into(),
-                            from_type: value.get_type().to_string(),
-                            span: head,
-                            help: None,
-                        }),
-                    }
+                    serde_urlencoded::to_string(row_vec).map_err(|_| ShellError::CantConvert {
+                        to_type: "URL".into(),
+                        from_type: value.get_type().to_string(),
+                        span: head,
+                        help: None,
+                    })
                 }
                 // Propagate existing errors
                 Value::Error { error, .. } => Err(*error),