3 files changed, 56 insertions, 16 deletions

diff --git a/riki.md b/riki.md
index 85abe81..14be721 100644
--- a/riki.md
+++ b/riki.md
@@ -381,7 +381,6 @@ then file output/dir/foo.html contains "href="/absolute""
 then file output/dir/foo.html contains "href="dir/sibling""
 then file output/dir/foo.html contains "href="dir/foo/child""
 then file output/dir/foo.html contains "href="dir/foo/child/grandchild""
-then file output/dir/foo.html contains "href="/missing"
 ~~~
 
 ~~~{#foo .file .markdown}
@@ -389,6 +388,20 @@ then file output/dir/foo.html contains "href="/missing"
 [[sibling]]
 [[child]]
 [[child/grandchild]]
+~~~
+
+## Wiki links to pages that don't exist
+
+_Requirement: Linking to a page that doesn't exist is an error._
+
+~~~scenario
+given an installed riki
+given file site/dir/foo.mdwn from badlink
+when I try to run riki build --plain-body site output
+then command fails
+~~~
+
+~~~{#badlink .file .markdown}
 [[missing]]
 ~~~
 
diff --git a/src/error.rs b/src/error.rs
index faaaaa8..fa8ddf2 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -43,4 +43,7 @@ pub enum SiteError {
 
     #[error("directive {0} is missing required argument {1}")]
     DirectiveUnknownArg(String, String),
+
+    #[error("link to missing page {1} on {0}")]
+    PageMissing(PathBuf, PathBuf),
 }
diff --git a/src/site.rs b/src/site.rs
index c1c7249..9bfa2bd 100644
--- a/src/site.rs
+++ b/src/site.rs
@@ -128,7 +128,7 @@ impl Site {
     pub fn resolve<P: AsRef<Path>>(&self, page: P, target: P) -> Result<PathBuf, SiteError> {
         let page = page.as_ref();
         let target = target.as_ref();
-        let resolved = self.resolve_helper(page, target);
+        let resolved = self.resolve_helper(page, target)?;
         trace!(
             "resolve: page={}, target={} -> {}",
             page.display(),
@@ -138,28 +138,28 @@ impl Site {
         Ok(resolved)
     }
 
-    fn resolve_helper(&self, page: &Path, target: &Path) -> PathBuf {
+    fn resolve_helper(&self, page: &Path, target: &Path) -> Result<PathBuf, SiteError> {
         // Is target absolute?
         if target.starts_with("/") {
-            return target.to_path_buf();
+            return Ok(target.to_path_buf());
         }
 
         // Does a sub-page exist?
         let path = page.join(target);
         if self.have_page(path.as_path()) {
-            return path;
+            return Ok(path);
         }
 
         // Does a sibling exist?
         if let Some(parent) = page.parent() {
             let path = parent.join(target);
             if self.have_page(path.as_path()) {
-                return path;
+                return Ok(path);
             }
         }
 
         // Nothing else worked, so make the target absolute.
-        PathBuf::from("/").join(target)
+        Err(SiteError::PageMissing(page.into(), target.into()))
     }
 
     fn have_page(&self, path: &Path) -> bool {
@@ -169,7 +169,7 @@ impl Site {
 
 #[cfg(test)]
 mod test {
-    use super::{Site, WikitextPage};
+    use super::{Site, SiteError, WikitextPage};
     use crate::page::MetaBuilder;
     use std::path::{Path, PathBuf};
 
@@ -187,13 +187,22 @@ mod test {
     #[test]
     fn absolute_link_resolves_to_absolute() {
         let site = Site::new(".", ".");
-        assert_eq!(site.resolve("/foo/bar", "/yo/yoyo").unwrap(), Path::new("/yo/yoyo"));
+        assert_eq!(
+            site.resolve("/foo/bar", "/yo/yoyo").unwrap(),
+            Path::new("/yo/yoyo")
+        );
     }
 
     #[test]
-    fn link_to_missing_resolves_to_absolute() {
+    fn link_to_missing_is_an_error() {
         let site = Site::new(".", ".");
-        assert_eq!(site.resolve("/foo/bar", "yo").unwrap(), Path::new("/yo"));
+        match site.resolve("/foo/bar", "yo") {
+            Err(SiteError::PageMissing(page, target)) => {
+                assert_eq!(target, PathBuf::from("yo"));
+                assert_eq!(page, PathBuf::from("/foo/bar"));
+            }
+            _ => panic!("unexpected success"),
+        }
     }
 
     #[test]
@@ -201,7 +210,10 @@ mod test {
         let mut site = Site::new(".", ".");
         site.add_wikitextpage(page("/foo/yo"));
         site.process().unwrap();
-        assert_eq!(site.resolve("/foo/bar", "yo").unwrap(), Path::new("/foo/yo"));
+        assert_eq!(
+            site.resolve("/foo/bar", "yo").unwrap(),
+            Path::new("/foo/yo")
+        );
     }
 
     #[test]
@@ -209,7 +221,10 @@ mod test {
         let mut site = Site::new(".", ".");
         site.add_wikitextpage(page("/foo/bar/yo"));
         site.process().unwrap();
-        assert_eq!(site.resolve("/foo/bar", "yo").unwrap(), Path::new("/foo/bar/yo"));
+        assert_eq!(
+            site.resolve("/foo/bar", "yo").unwrap(),
+            Path::new("/foo/bar/yo")
+        );
     }
 
     #[test]
@@ -218,14 +233,23 @@ mod test {
         site.add_wikitextpage(page("/foo/bar/yo"));
         site.add_wikitextpage(page("/foo/yo"));
         site.process().unwrap();
-        assert_eq!(site.resolve("/foo/bar", "yo").unwrap(), Path::new("/foo/bar/yo"));
+        assert_eq!(
+            site.resolve("/foo/bar", "yo").unwrap(),
+            Path::new("/foo/bar/yo")
+        );
     }
 
     #[test]
-    fn link_to_unrelated_subpage_resolves_absolute() {
+    fn link_to_unrelated_subpage_is_an_error() {
         let mut site = Site::new(".", ".");
         site.process().unwrap();
-        assert_eq!(site.resolve("/foo/bar", "yo/yoyo").unwrap(), Path::new("/yo/yoyo"));
+        match site.resolve("/foo/bar", "yo/yoyo") {
+            Err(SiteError::PageMissing(page, target)) => {
+                assert_eq!(target, PathBuf::from("yo/yoyo"));
+                assert_eq!(page, PathBuf::from("/foo/bar"));
+            }
+            _ => panic!("unexpected success"),
+        }
     }
 
     #[test]