Avoid generating links with empty inlines

src/parser/inlines.rs

@@ -9,8 +9,7 @@ use crate::nodes::{
 use crate::parser::shortcodes::NodeShortCode;
 use crate::parser::{unwrap_into_2, unwrap_into_copy, AutolinkType, Callback, Options, Reference};
 use crate::scanners;
-use crate::strings;
-use crate::strings::Case;
+use crate::strings::{self, is_blank, Case};
 use std::cell::{Cell, RefCell};
 use std::collections::HashMap;
 use std::convert::TryFrom;
@@ -1366,6 +1365,32 @@ impl<'a, 'r, 'o, 'd, 'i, 'c, 'subj> Subject<'a, 'r, 'o, 'd, 'i, 'c, 'subj> {
             ));
         }
 
+        // Ensure there was text if this was a link and not an image link
+        if !is_image {
+            let mut non_blank_found = false;
+            let mut tmpch = self.brackets[brackets_len - 1].inl_text.next_sibling();
+            while let Some(tmp) = tmpch {
+                match tmp.data.borrow().value {
+                    NodeValue::Text(ref s) if is_blank(s.as_bytes()) => (),
+                    _ => {
+                        non_blank_found = true;
+                        break;
+                    }
+                }
+
+                tmpch = tmp.next_sibling();
+            }
+
+            if !non_blank_found {
+                self.brackets.pop();
+                return Some(self.make_inline(
+                    NodeValue::Text("]".to_string()),
+                    self.pos - 1,
+                    self.pos - 1,
+                ));
+            }
+        }
+
         let after_link_text_pos = self.pos;
 
         // Try to find a link destination within parenthesis

src/tests/philomena.rs

@@ -128,6 +128,35 @@ fn philomena_images() {
     );
 }
 
+#[test]
+fn no_empty_link() {
+    html(
+        "[](https://example.com/evil.domain.for.seo.spam)",
+        "<p>[](https://example.com/evil.domain.for.seo.spam)</p>\n",
+    );
+
+    html(
+        "[    ](https://example.com/evil.domain.for.seo.spam)",
+        "<p>[    ](https://example.com/evil.domain.for.seo.spam)</p>\n",
+    );
+}
+
+#[test]
+fn empty_image_allowed() {
+    html(
+        "![   ](https://example.com/evil.domain.for.seo.spam)",
+        "<p><img src=\"https://example.com/evil.domain.for.seo.spam\" alt=\"   \" /></p>\n",
+    );
+}
+
+#[test]
+fn image_inside_link_allowed() {
+    html(
+        "[![](https://example.com/image.png)](https://example.com/)",
+        "<p><a href=\"https://example.com/\"><img src=\"https://example.com/image.png\" alt=\"\" /></a></p>\n",
+    );
+}
+
 #[test]
 fn image_mention() {
     html_opts_no_roundtrip(