feat: add healthcheckCmdNewLine config option

deployment/schema.json

@@ -34,6 +34,11 @@
     },
     "newLineKind": {
       "$ref": "#/definitions/newLineKind"
+    },
+    "healthcheckCmdNewLine": {
+      "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"
     }
   }
 }

src/configuration/builder.rs

@@ -64,6 +64,13 @@ impl ConfigurationBuilder {
     self.insert("newLineKind", value.to_string().into())
   }
 
+  /// 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`
+  pub fn healthcheck_cmd_new_line(&mut self, value: bool) -> &mut Self {
+    self.insert("healthcheckCmdNewLine", value.into())
+  }
+
   #[cfg(test)]
   pub(super) fn get_inner_config(&self) -> ConfigKeyMap {
     self.config.clone()
@@ -85,10 +92,13 @@ mod tests {
   #[test]
   fn check_all_values_set() {
     let mut config = ConfigurationBuilder::new();
-    config.new_line_kind(NewLineKind::CarriageReturnLineFeed).line_width(90);
+    config
+      .new_line_kind(NewLineKind::CarriageReturnLineFeed)
+      .line_width(90)
+      .healthcheck_cmd_new_line(true);
 
     let inner_config = config.get_inner_config();
-    assert_eq!(inner_config.len(), 2);
+    assert_eq!(inner_config.len(), 3);
     let diagnostics = resolve_config(inner_config, &Default::default()).diagnostics;
     assert_eq!(diagnostics.len(), 0);
   }

src/configuration/configuration.rs

@@ -7,4 +7,7 @@ use serde::Serialize;
 pub struct Configuration {
   pub line_width: u32,
   pub new_line_kind: NewLineKind,
+  /// 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,
 }

src/configuration/resolve_config.rs

@@ -40,6 +40,7 @@ pub fn resolve_config(config: ConfigKeyMap, global_config: &GlobalConfiguration)
       global_config.new_line_kind.unwrap_or(RECOMMENDED_GLOBAL_CONFIGURATION.new_line_kind),
       &mut diagnostics,
     ),
+    healthcheck_cmd_new_line: get_value(&mut config, "healthcheckCmdNewLine", false, &mut diagnostics),
   };
 
   diagnostics.extend(get_unknown_property_diagnostics(config));

src/generation/context.rs

@@ -9,7 +9,7 @@ use super::helpers::parse_comments;
 use crate::configuration::Configuration;
 
 pub struct Context<'a> {
-  pub _config: &'a Configuration,
+  pub config: &'a Configuration,
   pub dockerfile: &'a Dockerfile,
   pub text: &'a str,
   pub handled_comments: HashSet<usize>,
@@ -27,7 +27,7 @@ pub struct Context<'a> {
 impl<'a> Context<'a> {
   pub fn new(text: &'a str, dockerfile: &'a Dockerfile, config: &'a Configuration) -> Self {
     Self {
-      _config: config,
+      config,
       text,
       dockerfile,
       handled_comments: HashSet::new(),

src/generation/generate.rs

@@ -323,11 +323,13 @@ fn gen_healthcheck_instruction<'a>(node: &'a HealthcheckInstruction, context: &m
 
   // group the options and the nested command so they sit on one line when they
   // fit under the line width and otherwise break onto an aligned continuation
-  // line (#29). a break the author already wrote forces the multi-line form.
+  // line (#29). a break the author already wrote forces the multi-line form, as
+  // does `healthcheckCmdNewLine` when there's a command preceded by options.
   let first_line = node.span.relative_span(context.dockerfile).0;
   let command_span = node.cmd.as_ref().map(|c| c.span()).unwrap_or(node.span);
   let command_line = command_span.relative_span(context.dockerfile).0;
-  let force_use_new_lines = command_line > first_line;
+  let proactive_split = context.config.healthcheck_cmd_new_line && node.cmd.is_some() && !node.flags.is_empty();
+  let force_use_new_lines = command_line > first_line || proactive_split;
   items.extend(gen_grouped_values(
     vec![(flags_items, first_line), (command_items, command_line)],
     HEALTHCHECK_CONTINUATION_INDENT,

tests/specs/Healthcheck/Healthcheck_CmdNewLine.txt

@@ -0,0 +1,33 @@
+~~ healthcheckCmdNewLine: true ~~
+== should split CMD onto its own line when there are options ==
+HEALTHCHECK --interval=30s CMD curl -f http://localhost/
+
+[expect]
+HEALTHCHECK --interval=30s \
+  CMD curl -f http://localhost/
+
+== should split before an exec-form command ==
+HEALTHCHECK --retries=3 CMD ["curl", "-f", "http://localhost/"]
+
+[expect]
+HEALTHCHECK --retries=3 \
+  CMD ["curl", "-f", "http://localhost/"]
+
+== should not split when there are no options ==
+HEALTHCHECK CMD curl -f http://localhost/
+
+[expect]
+HEALTHCHECK CMD curl -f http://localhost/
+
+== should not split NONE ==
+HEALTHCHECK --interval=30s NONE
+
+[expect]
+HEALTHCHECK --interval=30s NONE
+
+== should collapse a continuation before NONE ==
+HEALTHCHECK --interval=30s \
+  NONE
+
+[expect]
+HEALTHCHECK --interval=30s NONE