feat: add indentStages config

Cargo.toml

@@ -25,7 +25,7 @@ wasm = ["serde_json", "dprint-core/wasm"]
 tracing = ["dprint-core/tracing"]
 
 [dependencies]
-dprint-core = { version = "0.68.1", features = ["formatting"], default-features = false }
+dprint-core = { version = "0.69.0", features = ["formatting"], default-features = false }
 dprint-core-macros = "0.1.0"
 monch = "0.6.0"
 serde = { version = "1.0.144", features = ["derive"] }

deployment/schema.json

@@ -39,6 +39,16 @@
       "description": "Whether to always break a HEALTHCHECK command onto its own continuation line when the instruction has options, even if it would fit on one line.",
       "default": false,
       "type": "boolean"
+    },
+    "indentStages": {
+      "description": "Whether to indent the body of each build stage—the instructions and comments that follow a FROM—by indentWidth spaces. The indentation is always spaces; useTabs is not honored.",
+      "default": false,
+      "type": "boolean"
+    },
+    "indentWidth": {
+      "description": "The number of spaces for an indent. Only used when indentStages is enabled.",
+      "default": 2,
+      "type": "number"
     }
   }
 }

src/configuration/builder.rs

@@ -71,6 +71,21 @@ impl ConfigurationBuilder {
     self.insert("healthcheckCmdNewLine", value.into())
   }
 
+  /// Whether to indent the body of each build stage - the instructions and
+  /// comments that follow a `FROM` - by `indent_width` spaces. The indentation
+  /// is always spaces; `useTabs` is not honored.
+  /// Default: `false`
+  pub fn indent_stages(&mut self, value: bool) -> &mut Self {
+    self.insert("indentStages", value.into())
+  }
+
+  /// The number of spaces for an indent. Only used when `indent_stages` is
+  /// enabled.
+  /// Default: 2
+  pub fn indent_width(&mut self, value: u8) -> &mut Self {
+    self.insert("indentWidth", (value as i32).into())
+  }
+
   #[cfg(test)]
   pub(super) fn get_inner_config(&self) -> ConfigKeyMap {
     self.config.clone()
@@ -95,10 +110,12 @@ mod tests {
     config
       .new_line_kind(NewLineKind::CarriageReturnLineFeed)
       .line_width(90)
-      .healthcheck_cmd_new_line(true);
+      .healthcheck_cmd_new_line(true)
+      .indent_stages(true)
+      .indent_width(4);
 
     let inner_config = config.get_inner_config();
-    assert_eq!(inner_config.len(), 3);
+    assert_eq!(inner_config.len(), 5);
     let diagnostics = resolve_config(inner_config, &Default::default()).diagnostics;
     assert_eq!(diagnostics.len(), 0);
   }
@@ -108,12 +125,14 @@ mod tests {
     let mut global_config = ConfigKeyMap::new();
     global_config.insert(String::from("lineWidth"), 90.into());
     global_config.insert(String::from("newLineKind"), "crlf".into());
+    global_config.insert(String::from("indentWidth"), 4.into());
     global_config.insert(String::from("useTabs"), true.into());
     let global_config = resolve_global_config(&mut global_config).config;
     let mut config_builder = ConfigurationBuilder::new();
     let config = config_builder.global_config(global_config).build();
     assert_eq!(config.line_width, 90);
     assert_eq!(config.new_line_kind, NewLineKind::CarriageReturnLineFeed);
+    assert_eq!(config.indent_width, 4);
   }
 
   #[test]
@@ -122,5 +141,17 @@ mod tests {
     let mut config_builder = ConfigurationBuilder::new();
     let config = config_builder.global_config(global_config).build();
     assert_eq!(config.new_line_kind, NewLineKind::LineFeed);
+    assert_eq!(config.indent_width, 2);
+    assert!(!config.indent_stages);
+  }
+
+  #[test]
+  fn override_global_indent_width() {
+    let mut global_config = ConfigKeyMap::new();
+    global_config.insert(String::from("indentWidth"), 4.into());
+    let global_config = resolve_global_config(&mut global_config).config;
+    let mut config_builder = ConfigurationBuilder::new();
+    let config = config_builder.global_config(global_config).indent_width(8).build();
+    assert_eq!(config.indent_width, 8);
   }
 }

src/configuration/configuration.rs

@@ -10,4 +10,11 @@ pub struct Configuration {
   /// Whether to always break a `HEALTHCHECK` command onto its own continuation
   /// line when the instruction has options, even if it would fit on one line.
   pub healthcheck_cmd_new_line: bool,
+  /// Whether to indent the body of each build stage - the instructions and
+  /// comments that follow a `FROM` - by `indent_width` spaces. The indentation
+  /// is always spaces; `useTabs` is not honored.
+  pub indent_stages: bool,
+  /// The number of spaces for an indent. Only used when `indent_stages` is
+  /// enabled.
+  pub indent_width: u8,
 }

src/configuration/resolve_config.rs

@@ -41,6 +41,13 @@ pub fn resolve_config(config: ConfigKeyMap, global_config: &GlobalConfiguration)
       &mut diagnostics,
     ),
     healthcheck_cmd_new_line: get_value(&mut config, "healthcheckCmdNewLine", false, &mut diagnostics),
+    indent_stages: get_value(&mut config, "indentStages", false, &mut diagnostics),
+    indent_width: get_value(
+      &mut config,
+      "indentWidth",
+      global_config.indent_width.unwrap_or(RECOMMENDED_GLOBAL_CONFIGURATION.indent_width),
+      &mut diagnostics,
+    ),
   };
 
   diagnostics.extend(get_unknown_property_diagnostics(config));

src/format_text.rs

@@ -64,6 +64,43 @@ mod test {
     }
   }
 
+  #[test]
+  fn indents_stages_with_carriage_returns() {
+    // a `\r` is never part of the indentation and never reaches the dedent
+    let text = format_with(
+      "FROM alpine\r\n    RUN foo \\\r\n      bar\r\n",
+      crate::configuration::ConfigurationBuilder::new().indent_stages(true),
+    );
+    assert_eq!(text, "FROM alpine\n  RUN foo \\\n    bar\n");
+  }
+
+  #[test]
+  fn indent_width_of_zero_does_not_indent_stages() {
+    let text = format_with(
+      "FROM alpine\nRUN echo hi\n",
+      crate::configuration::ConfigurationBuilder::new().indent_stages(true).indent_width(0),
+    );
+    assert_eq!(text, "FROM alpine\nRUN echo hi\n");
+  }
+
+  #[test]
+  fn huge_indent_width_is_capped_instead_of_overflowing_the_printer() {
+    // the printer stores its indent level in a `u8`, so the width is capped
+    let text = format_with(
+      "FROM alpine\nENV A=1 \\\n  B=2\n",
+      crate::configuration::ConfigurationBuilder::new().indent_stages(true).indent_width(255),
+    );
+    let indent = " ".repeat(200);
+    assert_eq!(text, format!("FROM alpine\n{0}ENV A=1 \\\n{0}    B=2\n", indent));
+  }
+
+  /// Formats the text, resolving the "already formatted" result to the input.
+  fn format_with(text: &str, builder: &mut crate::configuration::ConfigurationBuilder) -> String {
+    format_text(&std::path::PathBuf::from("Dockerfile"), text, &builder.build())
+      .unwrap()
+      .unwrap_or_else(|| text.to_string())
+  }
+
   #[test]
   fn comment_with_interior_tab_does_not_panic() {
     // a tab inside a comment must be emitted as a tab signal, not a raw tab

src/generation/context.rs

@@ -16,12 +16,15 @@ pub struct Context<'a> {
   current_node: Option<Node<'a>>,
   parent_stack: Vec<Node<'a>>,
   pub gen_string_content: bool,
-  /// whether the current breakable string is shell content whose insignificant
+  /// Whether the current breakable string is shell content whose insignificant
   /// whitespace runs should be collapsed
   pub collapse_shell_ws: bool,
-  /// the quote currently open while collapsing shell whitespace (carried across
+  /// The quote currently open while collapsing shell whitespace (carried across
   /// the breakable string's components), or `None` when outside a quote
   pub shell_quote: Option<char>,
+  /// The amount of leading whitespace to strip from the continuation lines of
+  /// the current instruction so the printer can re-indent them
+  pub dedent_width: usize,
 }
 
 impl<'a> Context<'a> {
@@ -36,6 +39,7 @@ impl<'a> Context<'a> {
       gen_string_content: false,
       collapse_shell_ws: false,
       shell_quote: None,
+      dedent_width: 0,
     }
   }