Merge #662

662: Preserve indentation in doc comments r=matklad a=kjeremy

Fixes #502 

Co-authored-by: Jeremy Kolb <kjeremy@gmail.com>

crates/ra_hir/src/docs.rs

@@ -27,10 +27,5 @@ pub trait Docs {
 }
 
 pub(crate) fn docs_from_ast(node: &impl ast::DocCommentsOwner) -> Option<Documentation> {
-    let comments = node.doc_comment_text();
-    if comments.is_empty() {
-        None
-    } else {
-        Some(Documentation::new(&comments))
-    }
+    node.doc_comment_text().map(|it| Documentation::new(&it))
 }

crates/ra_ide_api/src/call_info.rs

@@ -126,8 +126,7 @@ impl CallInfo {
         };
 
         let mut doc = None;
-        let docs = node.doc_comment_text();
-        if !docs.is_empty() {
+        if let Some(docs) = node.doc_comment_text() {
             // Massage markdown
             let mut processed_lines = Vec::new();
             let mut in_code_block = false;

crates/ra_ide_api/src/hover.rs

@@ -100,12 +100,7 @@ impl NavigationTarget {
     fn docs(&self, db: &RootDatabase) -> Option<String> {
         let node = self.node(db)?;
         fn doc_comments<N: ast::DocCommentsOwner>(node: &N) -> Option<String> {
-            let comments = node.doc_comment_text();
-            if comments.is_empty() {
-                None
-            } else {
-                Some(comments)
-            }
+            node.doc_comment_text()
         }
 
         visitor()

crates/ra_syntax/src/ast.rs

@@ -115,21 +115,38 @@ pub trait DocCommentsOwner: AstNode {
     }
 
     /// Returns the textual content of a doc comment block as a single string.
-    /// That is, strips leading `///` and joins lines
-    fn doc_comment_text(&self) -> std::string::String {
-        self.doc_comments()
+    /// That is, strips leading `///` (+ optional 1 character of whitespace)
+    /// and joins lines.
+    fn doc_comment_text(&self) -> Option<std::string::String> {
+        let docs = self
+            .doc_comments()
             .filter(|comment| comment.is_doc_comment())
             .map(|comment| {
-                let prefix = comment.prefix();
-                let trimmed = comment
-                    .text()
-                    .as_str()
-                    .trim()
-                    .trim_start_matches(prefix)
-                    .trim_start();
-                trimmed.to_owned()
+                let prefix_len = comment.prefix().len();
+
+                let line = comment.text().as_str();
+
+                // Determine if the prefix or prefix + 1 char is stripped
+                let pos = if line
+                    .chars()
+                    .nth(prefix_len)
+                    .map(|c| c.is_whitespace())
+                    .unwrap_or(false)
+                {
+                    prefix_len + 1
+                } else {
+                    prefix_len
+                };
+
+                line[pos..].to_owned()
             })
-            .join("\n")
+            .join("\n");
+
+        if docs.is_empty() {
+            None
+        } else {
+            Some(docs)
+        }
     }
 }
 
@@ -703,6 +720,18 @@ impl BindPat {
     }
 }
 
+#[test]
+fn test_doc_comment_none() {
+    let file = SourceFile::parse(
+        r#"
+        // non-doc
+        mod foo {}
+        "#,
+    );
+    let module = file.syntax().descendants().find_map(Module::cast).unwrap();
+    assert!(module.doc_comment_text().is_none());
+}
+
 #[test]
 fn test_doc_comment_of_items() {
     let file = SourceFile::parse(
@@ -713,5 +742,25 @@ fn test_doc_comment_of_items() {
         "#,
     );
     let module = file.syntax().descendants().find_map(Module::cast).unwrap();
-    assert_eq!("doc", module.doc_comment_text());
+    assert_eq!("doc", module.doc_comment_text().unwrap());
+}
+
+#[test]
+fn test_doc_comment_preserves_indents() {
+    let file = SourceFile::parse(
+        r#"
+        /// doc1
+        /// ```
+        /// fn foo() {
+        ///     // ...
+        /// }
+        /// ```
+        mod foo {}
+        "#,
+    );
+    let module = file.syntax().descendants().find_map(Module::cast).unwrap();
+    assert_eq!(
+        "doc1\n```\nfn foo() {\n    // ...\n}\n```",
+        module.doc_comment_text().unwrap()
+    );
 }