From 88dfede79db8eaf17c919543bb41ab4aae3a2be8 Mon Sep 17 00:00:00 2001
From: Lars Wirzenius <liw@liw.fi>
Date: Sun, 23 Oct 2022 11:28:12 +0300
Subject: fix: return error for wikitext syntax errors, instead of panic

Sponsored-by: author
---
 src/error.rs  | 10 ++++++++++
 src/parser.rs | 38 ++++++++------------------------------
 2 files changed, 18 insertions(+), 30 deletions(-)

diff --git a/src/error.rs b/src/error.rs
index 2a7d373..922f735 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -85,4 +85,14 @@ pub enum SiteError {
 
     #[error(transparent)]
     PageSpec(#[from] crate::pagespec::PageSpecError),
+
+    #[error("failed to parse wikitext, line {0}, column {1}: {2:?}")]
+    WikitextSyntax(usize, usize, Vec<crate::token::TokenKind>),
+}
+
+impl SiteError {
+    pub fn wikitext_syntax(line: usize, col: usize, tokens: &[crate::token::TokenKind]) -> Self {
+        let tokens = tokens.to_vec();
+        Self::WikitextSyntax(line, col, tokens)
+    }
 }
diff --git a/src/parser.rs b/src/parser.rs
index 5378f36..559ee3a 100644
--- a/src/parser.rs
+++ b/src/parser.rs
@@ -52,8 +52,7 @@ impl WikitextParser {
         let (line, col) = self.position();
         debug!("token at {}:{}", line, col);
         let snippet = match &self.tokens[..] {
-            [TokenKind::OpenBrackets, TokenKind::Word(target), TokenKind::CloseBrackets, ..] =>
-            {
+            [TokenKind::OpenBrackets, TokenKind::Word(target), TokenKind::CloseBrackets, ..] => {
                 let wikilink = WikiLink::new(target, target);
                 let snippet = Snippet::WikiLink(wikilink);
                 self.drain(3);
@@ -98,8 +97,7 @@ impl WikitextParser {
                             self.drain(1);
                             break;
                         }
-                        [TokenKind::Pipe, TokenKind::Word(word), TokenKind::CloseBrackets, ..] =>
-                        {
+                        [TokenKind::Pipe, TokenKind::Word(word), TokenKind::CloseBrackets, ..] => {
                             trace!("match |{:?}]]", word);
                             target = Some(word.to_string());
                             self.drain(3);
@@ -112,12 +110,7 @@ impl WikitextParser {
                             self.drain(3);
                             break;
                         }
-                        _ => panic!(
-                            "a can't parse line {} column {}: {:?}",
-                            line,
-                            col,
-                            &self.tokens[..5]
-                        ),
+                        _ => return Err(SiteError::wikitext_syntax(line, col, &self.tokens[..5])),
                     }
                 }
                 if target.is_none() {
@@ -126,8 +119,7 @@ impl WikitextParser {
                 let wikilink = WikiLink::new(&link_text, &target.unwrap());
                 Snippet::WikiLink(wikilink)
             }
-            [TokenKind::OpenBrackets, TokenKind::Bang, TokenKind::Word(name), ..] =>
-            {
+            [TokenKind::OpenBrackets, TokenKind::Bang, TokenKind::Word(name), ..] => {
                 trace!("match [[!{:?}", name);
                 let name = name.to_string();
                 let mut args = HashMap::new();
@@ -155,8 +147,7 @@ impl WikitextParser {
                             self.drain(2);
                             break;
                         }
-                        [TokenKind::Word(name), TokenKind::Equals, TokenKind::Word(value), ..] =>
-                        {
+                        [TokenKind::Word(name), TokenKind::Equals, TokenKind::Word(value), ..] => {
                             trace!("match {:?}={:?}", name, value);
                             args.insert(name.to_string(), value.to_string());
                             self.drain(3);
@@ -172,12 +163,7 @@ impl WikitextParser {
                             args.insert(value.to_string(), "".to_string());
                             self.drain(1);
                         }
-                        _ => panic!(
-                            "b can't parse line {} column {}: {:?}",
-                            line,
-                            col,
-                            &self.tokens[..5]
-                        ),
+                        _ => return Err(SiteError::wikitext_syntax(line, col, &self.tokens[..5])),
                     }
                 }
                 Snippet::Directive(ParsedDirective::new(&name, args)?)
@@ -204,12 +190,7 @@ impl WikitextParser {
                             self.drain(4);
                             break;
                         }
-                        _ => panic!(
-                            "c can't parse line {} column {}: {:?}",
-                            line,
-                            col,
-                            &self.tokens[..5]
-                        ),
+                        _ => return Err(SiteError::wikitext_syntax(line, col, &self.tokens[..5])),
                     }
                 }
                 Snippet::Markdown(format!("![{}]({})", link_text, target.unwrap()))
@@ -275,10 +256,7 @@ impl WikitextParser {
                 self.drain(1);
                 Snippet::Markdown("]]".into())
             }
-            _ => panic!(
-                "d can't parse line {} column {}: {:?}",
-                line, col, self.tokens
-            ),
+            _ => return Err(SiteError::wikitext_syntax(line, col, &self.tokens[..5])),
         };
         Ok(Some(snippet))
     }
-- 
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