refactor: Address position issues with unicode text

Author: xosnrdev

src/bors/handlers/trybuild.rs

@@ -20,7 +20,7 @@ use crate::github::{
     CommitSha, GithubUser, LabelTrigger, MergeError, PullRequest, PullRequestNumber,
 };
 use crate::permissions::PermissionType;
-use crate::utils::suppress_github_mentions;
+use crate::utils::text::suppress_github_mentions;
 
 use super::deny_request;
 use super::has_permission;

src/utils/mod.rs

@@ -1,99 +1,3 @@
 pub mod logging;
+pub mod text;
 pub mod timing;
-
-/// Converts GitHub @mentions to markdown-backticked text to prevent notifications.
-/// For example, "@user" becomes "`user`".
-///
-/// Handles GitHub mention formats:
-/// - Usernames (@username)
-/// - Teams (@org/team)
-/// - Nested teams (@org/team/subteam)
-///
-/// GitHub's nested team documentation:
-/// https://docs.github.com/en/organizations/organizing-members-into-teams/about-teams#nested-teams
-///
-/// Ignores email addresses and other @ symbols that don't match GitHub mention patterns.
-pub fn suppress_github_mentions(text: &str) -> String {
-    if text.is_empty() || !text.contains('@') {
-        return text.to_string();
-    }
-
-    let segment = r"[A-Za-z0-9][A-Za-z0-9\-]{0,38}";
-    let pattern = format!(r"@{0}(?:/{0})*", segment);
-
-    let re = regex::Regex::new(&pattern).unwrap();
-    re.replace_all(text, |caps: &regex::Captures| {
-        let mention = &caps[0];
-        let position = caps.get(0).unwrap().start();
-
-        if !is_github_mention(text, mention, position) {
-            return mention.to_string();
-        }
-
-        let name = &mention[1..]; // Drop the @ symbol
-        format!("`{}`", name)
-    })
-    .to_string()
-}
-
-// Determines if a potential mention would actually trigger a notification
-fn is_github_mention(text: &str, mention: &str, pos: usize) -> bool {
-    // Not a valid mention if preceded by alphanumeric or underscore (email)
-    if pos > 0 {
-        let c = text.chars().nth(pos - 1).unwrap();
-        if c.is_alphanumeric() || c == '_' {
-            return false;
-        }
-    }
-
-    // Check if followed by invalid character
-    let end = pos + mention.len();
-    if end < text.len() {
-        let next_char = text.chars().nth(end).unwrap();
-        if next_char.is_alphanumeric() || next_char == '_' || next_char == '-' {
-            return false;
-        }
-    }
-
-    true
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn test_suppress_github_mentions() {
-        // User mentions
-        assert_eq!(suppress_github_mentions("Hello @user"), "Hello `user`");
-
-        // Org team mentions
-        assert_eq!(suppress_github_mentions("@org/team"), "`org/team`");
-        assert_eq!(
-            suppress_github_mentions("@org/team/subteam"),
-            "`org/team/subteam`"
-        );
-        assert_eq!(
-            suppress_github_mentions("@big/team/sub/group"),
-            "`big/team/sub/group`"
-        );
-        assert_eq!(
-            suppress_github_mentions("Thanks @user, @rust-lang/libs and @github/docs/content!"),
-            "Thanks `user`, `rust-lang/libs` and `github/docs/content`!"
-        );
-
-        // Non mentions
-        assert_eq!(suppress_github_mentions("@"), "@");
-        assert_eq!(suppress_github_mentions(""), "");
-        assert_eq!(
-            suppress_github_mentions("No mentions here"),
-            "No mentions here"
-        );
-        assert_eq!(
-            suppress_github_mentions("user@example.com"),
-            "user@example.com"
-        );
-
-        assert_eq!(suppress_github_mentions("@user_test"), "@user_test");
-    }
-}

src/utils/text.rs

@@ -0,0 +1,95 @@
+use regex::{Captures, Regex};
+
+/// Replaces valid GitHub @mentions with backticks to prevent accidental pings
+///
+/// For example:
+/// "@user" -> "`@user`".
+/// "@org/team" -> "`@org/team`".
+/// "@org/team/subteam" -> "`@org/team/subteam`".
+pub fn suppress_github_mentions(text: &str) -> String {
+    if text.is_empty() || !text.contains('@') {
+        return text.to_string();
+    }
+
+    let segment = r"[a-zA-Z0-9][a-zA-Z0-9\-]{0,38}";
+    let pattern = format!(
+        r"(^|[^a-zA-Z0-9_])(@{0}(?:/{0})*)($|[^a-zA-Z0-9_\-])",
+        segment
+    );
+
+    let re = Regex::new(&pattern).unwrap();
+    re.replace_all(text, |caps: &Captures| {
+        // Group 1: The character before the mention (or start of string)
+        // Group 2: The @mention itself
+        // Group 3: The character after the mention (or end of string)
+        format!("{}`{}`{}", &caps[1], &caps[2], &caps[3])
+    })
+    .to_string()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn basic_mentions() {
+        assert_eq!(suppress_github_mentions("Hello @user"), "Hello `@user`");
+        assert_eq!(
+            suppress_github_mentions("Ping @developer"),
+            "Ping `@developer`"
+        );
+        assert_eq!(
+            suppress_github_mentions("Multiple @user1 and @user2"),
+            "Multiple `@user1` and `@user2`"
+        );
+    }
+
+    #[test]
+    fn team_mentions() {
+        assert_eq!(suppress_github_mentions("@org/team"), "`@org/team`");
+        assert_eq!(
+            suppress_github_mentions("@rust-lang/libs"),
+            "`@rust-lang/libs`"
+        );
+        assert_eq!(
+            suppress_github_mentions("@org/team/subteam"),
+            "`@org/team/subteam`"
+        );
+    }
+
+    #[test]
+    fn mention_boundaries() {
+        // Adjacent punctuation
+        assert_eq!(
+            suppress_github_mentions("Hello,@user! How are you?"),
+            "Hello,`@user`! How are you?"
+        );
+
+        // Email addresses
+        assert_eq!(
+            suppress_github_mentions("user@example.com"),
+            "user@example.com"
+        );
+
+        // Invalid mentions
+        assert_eq!(suppress_github_mentions("@-user"), "@-user");
+        assert_eq!(suppress_github_mentions("word@user"), "word@user");
+        assert_eq!(suppress_github_mentions("@user_next"), "@user_next");
+    }
+
+    #[test]
+    fn edge_cases() {
+        // Empty input
+        assert_eq!(suppress_github_mentions(""), "");
+
+        // Minimum valid mention
+        assert_eq!(suppress_github_mentions("@a"), "`@a`");
+
+        // Maximum length mention
+        let long_mention = "@".to_string() + &"a".repeat(39);
+        assert_eq!(
+            suppress_github_mentions(&long_mention),
+            format!("`{long_mention}`")
+        );
+    }
+}