fix(pretty_print): close a lone compact select item under select

crates/pgls_pretty_print/src/nodes/mod.rs

@@ -660,6 +660,34 @@ pub(super) fn emit_condition_on_keyword_line(e: &mut EventEmitter, condition: &N
     }
 }
 
+/// Whether a select item without an alias, which would continue on a line of its own, is written as
+/// a name or keyword followed by
+/// parentheses that hold everything that can break: a function call, `coalesce(...)`, `cast(...)`,
+/// a subquery, ...
+pub(super) fn breaks_only_inside_its_parentheses(e: &EventEmitter, item: &Node) -> bool {
+    let Some(NodeEnum::ResTarget(target)) = item.node.as_ref() else {
+        return false;
+    };
+    if !target.name.is_empty() || !target.indirection.is_empty() {
+        return false;
+    }
+    let Some(value) = target.val.as_deref() else {
+        return false;
+    };
+    match value.node.as_ref() {
+        // FILTER, WITHIN GROUP and OVER continue the call on lines of their own.
+        Some(NodeEnum::FuncCall(call)) => {
+            call.agg_filter.is_none() && call.over.is_none() && !call.agg_within_group
+        }
+        Some(NodeEnum::CoalesceExpr(_) | NodeEnum::MinMaxExpr(_) | NodeEnum::XmlSerialize(_)) => {
+            true
+        }
+        Some(NodeEnum::TypeCast(_)) => matches!(e.config().cast_style, crate::CastStyle::Cast),
+        Some(NodeEnum::SubLink(_)) => breaks_only_inside_a_subquery(value),
+        _ => false,
+    }
+}
+
 fn breaks_only_inside_a_subquery(node: &Node) -> bool {
     use pgls_query::protobuf::{AExprKind, BoolExprType, SubLinkType};
 

crates/pgls_pretty_print/src/nodes/select_stmt.rs

@@ -200,18 +200,30 @@ fn emit_select_stmt_impl(e: &mut EventEmitter, n: &SelectStmt, with_semicolon: b
         }
 
         if !n.target_list.is_empty() {
-            e.indent_start();
-
             // Compact keeps a lone item on the SELECT line, `select 1`; a list of several still
-            // puts one item per line.
-            match e.config().clause_body_style {
-                ClauseBodyStyle::Compact if n.target_list.len() == 1 => e.space(),
-                _ => super::emit_layout_break(e),
+            // puts one item per line. The indent is for the item's continuation lines, which an
+            // item that only breaks inside its parentheses, `coalesce(...)`, doesn't have: indented,
+            // its arguments would sit two levels in and its `)` one level in.
+            let lone_compact_item =
+                matches!(e.config().clause_body_style, ClauseBodyStyle::Compact)
+                    && n.target_list.len() == 1;
+            let indent = !(lone_compact_item
+                && super::breaks_only_inside_its_parentheses(e, &n.target_list[0]));
+
+            if indent {
+                e.indent_start();
+            }
+            if lone_compact_item {
+                e.space();
+            } else {
+                super::emit_layout_break(e);
             }
 
             emit_comma_separated_list_with_layout_break(e, &n.target_list, super::emit_node);
 
-            e.indent_end();
+            if indent {
+                e.indent_end();
+            }
         }
 
         // Emit INTO clause if present (SELECT ... INTO table_name)

crates/pgls_pretty_print/tests/snapshots/multi/tests__compact_select_list_100.snap

@@ -39,10 +39,10 @@ select case
 from users;
 
 select json_build_object(
-    'identifier', users.id,
-    'display_name', users.name,
-    'email_address', users.email
-  )
+  'identifier', users.id,
+  'display_name', users.name,
+  'email_address', users.email
+)
 from users;
 
 select first_really_long_column_name_here + second_really_long_column_name_here + third_long_column

crates/pgls_pretty_print/tests/snapshots/multi/tests__compact_select_list_80.snap

@@ -42,10 +42,10 @@ select case
 from users;
 
 select json_build_object(
-    'identifier', users.id,
-    'display_name', users.name,
-    'email_address', users.email
-  )
+  'identifier', users.id,
+  'display_name', users.name,
+  'email_address', users.email
+)
 from users;
 
 select first_really_long_column_name_here +

crates/pgls_pretty_print/tests/snapshots/multi/tests__compact_select_list_expanded_100.snap

@@ -55,10 +55,10 @@ select case
 from users;
 
 select json_build_object(
-    'identifier', users.id,
-    'display_name', users.name,
-    'email_address', users.email
-  )
+  'identifier', users.id,
+  'display_name', users.name,
+  'email_address', users.email
+)
 from users;
 
 select first_really_long_column_name_here + second_really_long_column_name_here + third_long_column

crates/pgls_pretty_print/tests/snapshots/multi/tests__compact_select_list_expanded_80.snap

@@ -55,10 +55,10 @@ select case
 from users;
 
 select json_build_object(
-    'identifier', users.id,
-    'display_name', users.name,
-    'email_address', users.email
-  )
+  'identifier', users.id,
+  'display_name', users.name,
+  'email_address', users.email
+)
 from users;
 
 select first_really_long_column_name_here +

crates/pgls_pretty_print/tests/snapshots/multi/tests__compact_select_list_leading_100.snap

@@ -39,10 +39,10 @@ select case
 from users;
 
 select json_build_object(
-    'identifier', users.id
-    , 'display_name', users.name
-    , 'email_address', users.email
-  )
+  'identifier', users.id
+  , 'display_name', users.name
+  , 'email_address', users.email
+)
 from users;
 
 select first_really_long_column_name_here + second_really_long_column_name_here + third_long_column

crates/pgls_pretty_print/tests/snapshots/multi/tests__compact_select_list_leading_80.snap

@@ -42,10 +42,10 @@ select case
 from users;
 
 select json_build_object(
-    'identifier', users.id
-    , 'display_name', users.name
-    , 'email_address', users.email
-  )
+  'identifier', users.id
+  , 'display_name', users.name
+  , 'email_address', users.email
+)
 from users;
 
 select first_really_long_column_name_here +

crates/pgls_pretty_print/tests/snapshots/multi/tests__scalar_subquery_expanded_100.snap

@@ -37,14 +37,14 @@ select *
 from t
 where a = (
   select coalesce(
-      (
-        select max(x)
-        from y
-        where y.id = t.id
-          and y.kind = 'some kind of value'
-      ),
-      0
-    )
+    (
+      select max(x)
+      from y
+      where y.id = t.id
+        and y.kind = 'some kind of value'
+    ),
+    0
+  )
 );
 
 select *

crates/pgls_pretty_print/tests/snapshots/multi/tests__scalar_subquery_expanded_80.snap

@@ -37,14 +37,14 @@ select *
 from t
 where a = (
   select coalesce(
-      (
-        select max(x)
-        from y
-        where y.id = t.id
-          and y.kind = 'some kind of value'
-      ),
-      0
-    )
+    (
+      select max(x)
+      from y
+      where y.id = t.id
+        and y.kind = 'some kind of value'
+    ),
+    0
+  )
 );
 
 select *

crates/pgls_pretty_print/tests/subquery_layout.rs

@@ -119,3 +119,29 @@ fn a_subquery_opened_on_the_on_line_closes_under_on() {
     assert!(output.contains("\n  on u.id = (\n    select\n"), "{output}");
     assert!(output.ends_with("\n  );"), "{output}");
 }
+
+#[test]
+fn a_lone_compact_select_item_closes_under_select() {
+    let config = FormatConfig {
+        clause_body_style: ClauseBodyStyle::Compact,
+        line_width: 60,
+        ..Default::default()
+    };
+    assert_eq!(
+        format_idempotently(
+            "select coalesce(some_long_column_name, another_long_column_name, 0) from t",
+            &config,
+        ),
+        "select coalesce(\n  some_long_column_name,\n  another_long_column_name,\n  0\n)\nfrom t;"
+    );
+
+    // An item with continuation lines of its own keeps the indent for them.
+    let output = format_idempotently(
+        "select some_long_column_name + another_long_column_name + a_third_long_column from t",
+        &config,
+    );
+    assert_eq!(
+        output,
+        "select some_long_column_name + another_long_column_name +\n  a_third_long_column\nfrom t;"
+    );
+}