headings: headings can have up to 3 leading whitespace

src/format.rs

@@ -90,8 +90,9 @@ pub fn shift_headings(raw: &str, levels: usize) -> String {
             }
         }
 
-        if curr_fence.is_none() && raw_line.starts_with('#') {
-            let heading = handle_heading(raw_line, levels);
+        let heading_line = &trim_leading_whitespace(raw_line, 3);
+        if curr_fence.is_none() && heading_line.starts_with('#') {
+            let heading = handle_heading(heading_line, levels);
             result.push_str(&heading);
         } else {
             result.push_str(raw_line);
@@ -145,7 +146,6 @@ pub fn get_fence(line: &str, allow_info: bool) -> Option<(usize, char)> {
 pub fn handle_heading(line: &str, levels: usize) -> String {
     let chars = line.chars();
 
-    // let mut leading_trivials: String = String::new();
     let mut hashes = String::new();
     let mut rest = String::new();
     for char in chars {

src/snapshots/nixdoc__test__headings.snap.new

@@ -0,0 +1,109 @@
+---
+source: src/test.rs
+assertion_line: 168
+expression: output
+---
+### h1-heading
+
+#### h2-heading
+
+3 leading whitespaces are okay for headings
+
+#### h2 heading
+
+    # code block
+
+
+#### h2-heading-with-id {#some-id}
+
+Indented code block
+
+    # Code comment
+    a = 1;
+
+##### h3-heading
+
+```nix
+# A comment should not be shifted
+```
+
+##### annother heading
+
+```
+# Some pseudocode
+map a from b -> 1
+```
+
+##### indented (0-3) fences
+
+3 leading whitespaces are okay for code fences
+
+  ``` lang info
+# Some pseudocode
+map a from b -> 1
+   ```
+
+##### indented (0-3) fences asymmetric
+
+```
+# Some pseudocode
+map a from b -> 1
+   ```
+
+##### More closing fences than opening
+
+````
+# Some pseudocode
+map a from b -> 1
+```````
+
+##### Some heading
+
+````nix
+/**
+   ```nix
+   # A nested comment should not be shifted
+   ```
+*/
+1
+# A comment
+````
+
+###### h4-heading
+
+Nested tilde fences
+
+~~~~~nix
+/*
+   ~~~~nix
+      /**
+         ~~~nix
+            # A nested comment should not be shifted
+            42
+         ~~~
+      */
+      1
+      # A nested comment ^
+   ~~~~
+*/
+# A comment ^
+foo
+~~~~~
+
+###### h5-heading
+
+Mixed fences
+
+~~~nix
+/**
+   ```nix
+   # A nested comment should not be shifted
+   ```
+*/
+1
+# A comment
+~~~
+
+###### h6-heading
+
+This should be h6 as well

test/headings.md

@@ -2,8 +2,20 @@
 
 ## h2-heading
 
+3 leading whitespaces are okay for headings
+
+   ## h2 heading
+
+    # code block
+
+
 ## h2-heading-with-id {#some-id}
 
+Indented code block
+
+    # Code comment
+    a = 1;
+
 ### h3-heading
 
 ```nix
@@ -19,6 +31,8 @@ map a from b -> 1
 
 ### indented (0-3) fences
 
+3 leading whitespaces are okay for code fences
+
   ``` lang info
 # Some pseudocode
 map a from b -> 1