refactor: add chain child indent options

Author: calebcartwright

Configurations.md

@@ -392,39 +392,135 @@ fn example() {
 ## `chains_block_parent_indent_children`
 Determines whether to indent the child chain items of a chain that beings with a block-like parent element when `indent_style` is `Block`.
 
-- **Default value**: `false`
-- **Possible values**: `true`, `false`
+- **Default value**: `"OnlyWithParent"`
+- **Possible values**: `"Never"`, `"Always"`, `"OnlyWithParent"`
 - **Stable**: No (tracking issue: ...)
 
-#### `false` (default):
+#### `OnlyWithParent` (default):
+Only indent the children chain elements of a block-like parent element if the parent's body was indented.
 
 ```rust
+// chains_block_parent_indent_parent_item: "OnlyTupleLitsAndSimpleCalls"
+#![rustfmt::skip]
 fn example() {
-    StructA {
-        test_test: some_value,
-    }
-    .foo()
+    let all = very_very_very_very_very_long_fun_name(
+            very_very_very_very_very_very_very_very_very_long_var_name,
+        )
+        .iter()
+        .map(|x| x + very_very_very_very_very_very_long_var_name);
+      
+    foo(|x| {
+        // ....
+    })
     .bar()
     .baz()
-    .qux();
+    .unwrap();
+  
+    StructA {
+            test_test: some_value,
+        }
+        .do_stuff(StructB {
+            test_test_b: other_value,
+        })
+        .foo()
+        .aaa_aaa();
+
+    let y = if some_condition {
+        // foo
+        val1
+    } else {
+        // bar
+        val2
+    }
+    .method_call()
+    .other_call()
+    .another();
 }
 ```
 
-#### `true`:
+#### `Always`:
+Always indent the children chain elements of a block-like parent element, regardless of whether the parent element body was indented.
 
 ```rust
 fn example() {
+    let all = very_very_very_very_very_long_fun_name(
+        very_very_very_very_very_very_very_very_very_long_var_name,
+    )
+        .iter()
+        .map(|x| x + very_very_very_very_very_very_long_var_name);
+
+    foo(|x| {
+        // ....
+    })
+        .bar()
+        .baz()
+        .unwrap();
+
     StructA {
         test_test: some_value,
     }
+        .do_stuff(StructB {
+            test_test_b: other_value,
+        })
         .foo()
-        .bar()
-        .baz()
-        .qux();
+        .aaa_aaa();
+
+    let y = if some_condition {
+        // foo
+        val1
+    } else {
+        // bar
+        val2
+    }
+        .method_call()
+        .other_call()
+        .another();
 }
 ```
 
-See also: [`indent_style`](#indent_style).
+#### `Never`:
+Never indent the children chain elements of a block-like parent element, regardless of whether the parent element body was indented.
+
+```rust
+// chains_block_parent_indent_parent_item: "OnlyTupleLitsAndSimpleCalls"
+#![rustfmt::skip]
+fn example() {
+    let all = very_very_very_very_very_long_fun_name(
+            very_very_very_very_very_very_very_very_very_long_var_name,
+        )
+    .iter()
+    .map(|x| x + very_very_very_very_very_very_long_var_name);
+      
+    foo(|x| {
+        // ....
+    })
+    .bar()
+    .baz()
+    .unwrap();
+  
+    StructA {
+            test_test: some_value,
+        }
+    .do_stuff(StructB {
+        test_test_b: other_value,
+    })
+    .foo()
+    .aaa_aaa();
+
+    let y = if some_condition {
+        // foo
+        val1
+    } else {
+        // bar
+        val2
+    }
+    .method_call()
+    .other_call()
+    .another();
+}
+```
+
+See also: [`indent_style`](#indent_style), [`chains_block_parent_indent_parent_item`](#chains_block_parent_indent_parent_item).
 
 ## `chains_block_parent_indent_parent_item`
 Determines whether block-like chain parents are indented when `indent_style` is `Block`.

src/chains.rs

@@ -63,7 +63,7 @@ use syntax::{ast, ptr};
 
 use crate::closures::rewrite_closure;
 use crate::comment::{rewrite_comment, CharClasses, FullCodeCharKind, RichChar};
-use crate::config::{ChainsBlockParentElementIndent, IndentStyle};
+use crate::config::{ChainsBlockParentChildrenIndent, ChainsBlockParentElementIndent, IndentStyle};
 use crate::expr::rewrite_call;
 use crate::lists::extract_pre_comment;
 use crate::macros::convert_try_mac;
@@ -924,12 +924,17 @@ impl<'a> ChainFormatter for ChainFormatterBlock<'a> {
     }
 
     fn child_shape(&self, context: &RewriteContext<'_>, shape: Shape) -> Option<Shape> {
-        let always_indent_children = context.config.chains_block_parent_indent_children();
+        let indent_style = context.config.chains_block_parent_indent_children();
+        let indent_block_like_parent_children = match indent_style {
+            ChainsBlockParentChildrenIndent::Always => true,
+            ChainsBlockParentChildrenIndent::Never => false,
+            ChainsBlockParentChildrenIndent::OnlyWithParent if self.parent_body_forced_indent => {
+                true
+            }
+            _ => false,
+        };
         Some(
-            if !self.root_ends_with_block
-                || always_indent_children
-                || self.parent_body_forced_indent
-            {
+            if !self.root_ends_with_block || indent_block_like_parent_children {
                 shape.block_indent(context.config.tab_spaces())
             } else {
                 shape.block_indent(0)

src/config/mod.rs

@@ -66,7 +66,10 @@ create_config! {
     merge_imports: bool, false, false, "Merge imports";
 
     // Chains
-    chains_block_parent_indent_children: bool, false, false,
+    chains_block_parent_indent_children:
+        ChainsBlockParentChildrenIndent,
+        ChainsBlockParentChildrenIndent::OnlyWithParent,
+        false,
         "Determines whether to indent the child chain items of a chain that beings with/
         a block-like parent element";
     chains_block_parent_indent_parent_item:
@@ -519,7 +522,7 @@ where_single_line = false
 imports_indent = "Block"
 imports_layout = "Mixed"
 merge_imports = false
-chains_block_parent_indent_children = false
+chains_block_parent_indent_children = "OnlyWithParent"
 chains_block_parent_indent_parent_item = "Never"
 reorder_imports = true
 reorder_modules = true

src/config/options.rs

@@ -187,6 +187,16 @@ pub enum ChainsBlockParentElementIndent {
     OnlyTupleLitsAndSimpleCalls,
 }
 
+#[config_type]
+pub enum ChainsBlockParentChildrenIndent {
+    /// Never indent the children chain elements of a block-like parent element.
+    Never,
+    /// Always indent the children chain elements of a block-like parent element.
+    Always,
+    /// Only indent the children chain elements if the block-like parent body is indented.
+    OnlyWithParent,
+}
+
 #[derive(Deserialize, Serialize, Clone, Debug, PartialEq)]
 pub struct WidthHeuristics {
     // Maximum width of the args of a function call before falling back

tests/source/chains_multiline_parent_always.rs

@@ -1,4 +1,3 @@
-// rustfmt-chains_block_parent_indent_children: true
 // rustfmt-chains_block_parent_indent_parent_item: Always
 // rustfmt-use_small_heuristics: Off
 

tests/source/chains_multiline_parent_never.rs

@@ -1,4 +1,3 @@
-// rustfmt-chains_block_parent_indent_children: false
 // rustfmt-chains_block_parent_indent_parent_item: Never
 
 fn main() {

tests/source/chains_multiline_parent_simple_calls.rs

@@ -1,4 +1,3 @@
-// rustfmt-chains_block_parent_indent_children: true
 // rustfmt-chains_block_parent_indent_parent_item: OnlySimpleCalls
 
 fn main() {

tests/source/chains_multiline_parent_tuples_and_simple_calls.rs

@@ -1,4 +1,3 @@
-// rustfmt-chains_block_parent_indent_children: true
 // rustfmt-chains_block_parent_indent_parent_item: OnlyTupleLitsAndSimpleCalls
 
 fn main() {

tests/target/chains_multiline_parent_always.rs

@@ -1,4 +1,3 @@
-// rustfmt-chains_block_parent_indent_children: true
 // rustfmt-chains_block_parent_indent_parent_item: Always
 // rustfmt-use_small_heuristics: Off
 
@@ -90,10 +89,10 @@ fn main() {
         body.extend(chunk);
         Ok(body)
     })
-        .and_then(move |body| {
-            let req = Request::from_parts(parts, body);
-            f(req).map_err(|_| io::Error::new(io::ErrorKind::Other, ""))
-        });
+    .and_then(move |body| {
+        let req = Request::from_parts(parts, body);
+        f(req).map_err(|_| io::Error::new(io::ErrorKind::Other, ""))
+    });
 
     aaaaaaaaaaaaaaaa
         .map(|x| {
@@ -318,14 +317,14 @@ fn issue_2773() {
         // do stuff
         None
     })
-        .or_else(|| {
-            // do other stuff
-            None
-        })
-        .and_then(|val| {
-            // do this stuff
-            None
-        });
+    .or_else(|| {
+        // do other stuff
+        None
+    })
+    .and_then(|val| {
+        // do this stuff
+        None
+    });
 }
 
 fn issue_3034() {

tests/target/chains_multiline_parent_never.rs

@@ -1,4 +1,3 @@
-// rustfmt-chains_block_parent_indent_children: false
 // rustfmt-chains_block_parent_indent_parent_item: Never
 
 fn main() {

tests/target/chains_multiline_parent_simple_calls.rs

@@ -1,4 +1,3 @@
-// rustfmt-chains_block_parent_indent_children: true
 // rustfmt-chains_block_parent_indent_parent_item: OnlySimpleCalls
 
 fn main() {
@@ -11,19 +10,19 @@ fn main() {
     StructA {
         test_test: some_value,
     }
-        .do_stuff(StructB {
+    .do_stuff(StructB {
+        test_test_b: other_value,
+    })
+    .aaa_aaa()
+    .do_stuff(
+        StructB {
             test_test_b: other_value,
-        })
-        .aaa_aaa()
-        .do_stuff(
-            StructB {
-                test_test_b: other_value,
-            }
-                .ddd_ddd()
-                .eee_eee(),
-        )
-        .bbb_bbb()
-        .ccc_ccc();
+        }
+        .ddd_ddd()
+        .eee_eee(),
+    )
+    .bbb_bbb()
+    .ccc_ccc();
     let more = 13;
     let other = vec![1, 2, 3]
         .iter()
@@ -32,7 +31,7 @@ fn main() {
     foo(|x| {
         // ....
     })
-        .bar()
-        .baz()
-        .unwrap();
+    .bar()
+    .baz()
+    .unwrap();
 }

tests/target/chains_multiline_parent_tuples_and_simple_calls.rs

@@ -1,4 +1,3 @@
-// rustfmt-chains_block_parent_indent_children: true
 // rustfmt-chains_block_parent_indent_parent_item: OnlyTupleLitsAndSimpleCalls
 
 fn main() {
@@ -32,7 +31,7 @@ fn main() {
     foo(|x| {
         // ....
     })
-        .bar()
-        .baz()
-        .unwrap();
+    .bar()
+    .baz()
+    .unwrap();
 }