Support filtering content mentions by paths

src/config.rs

@@ -299,6 +299,9 @@ pub(crate) struct MentionsEntryConfig {
     #[serde(alias = "type")]
     #[serde(default)]
     pub(crate) type_: MentionsEntryType,
+    /// Additional path globs to filter; primarily useful for `type = "content"`
+    #[serde(default)]
+    pub(crate) trigger_files: Vec<String>,
     pub(crate) message: Option<String>,
     #[serde(default)]
     pub(crate) cc: Vec<String>,
@@ -951,6 +954,12 @@ mod tests {
             message = "This is a message."
             cc = ["@someone"]
 
+            [mentions."miri"]
+            type = "content"
+            trigger_files = ["library/1", "library/2"]
+            message = "This is a message."
+            cc = ["@someone"]
+
             [shortcut]
 
             [issue-links]
@@ -1048,6 +1057,7 @@ mod tests {
                             "src/".to_string(),
                             MentionsEntryConfig {
                                 type_: MentionsEntryType::Filename,
+                                trigger_files: vec![],
                                 message: None,
                                 cc: vec!["@someone".to_string()]
                             }
@@ -1056,6 +1066,7 @@ mod tests {
                             "target/".to_string(),
                             MentionsEntryConfig {
                                 type_: MentionsEntryType::Filename,
+                                trigger_files: vec![],
                                 message: Some("This is a message.".to_string()),
                                 cc: vec!["@someone".to_string()]
                             }
@@ -1064,10 +1075,23 @@ mod tests {
                             "#[rustc_attr]".to_string(),
                             MentionsEntryConfig {
                                 type_: MentionsEntryType::Content,
+                                trigger_files: vec![],
+                                message: Some("This is a message.".to_string()),
+                                cc: vec!["@someone".to_string()]
+                            }
+                        ),
+                        (
+                            "miri".to_string(),
+                            MentionsEntryConfig {
+                                type_: MentionsEntryType::Content,
+                                trigger_files: vec![
+                                    "library/1".to_string(),
+                                    "library/2".to_string()
+                                ],
                                 message: Some("This is a message.".to_string()),
                                 cc: vec!["@someone".to_string()]
                             }
-                        )
+                        ),
                     ])
                 }),
                 no_merges: None,

src/handlers/check_commits/validate_config.rs

@@ -96,9 +96,22 @@ fn validate_parsed_config(config: &Config) -> Result<(), String> {
         };
 
     if let Some(mentions) = &config.mentions {
-        for (entry, MentionsEntryConfig { type_, .. }) in &mentions.entries {
+        for (entry, cfg @ MentionsEntryConfig { type_, .. }) in &mentions.entries {
             if type_ == &MentionsEntryType::Filename {
                 validate_pattern(entry, &format!("`[mentions.\"{entry}\"]`"))?;
+                if !cfg.trigger_files.is_empty() {
+                    return Err(format!(
+                        "Invalid `triagebot.toml`:\n\
+                        `[mentions.\"{entry}\"]` has `trigger_files` \
+                          which is only valid for `type = \"content\"`."
+                    ));
+                }
+            }
+            for file in &cfg.trigger_files {
+                validate_pattern(
+                    file,
+                    &format!("`[mentions.\"{entry}\"] trigger_files \"{file}\"`"),
+                )?;
             }
         }
     }

src/handlers/mentions.rs

@@ -85,7 +85,7 @@ pub(super) async fn parse_input(
     let to_mention: Vec<_> = config
         .entries
         .iter()
-        .filter_map(|(entry, MentionsEntryConfig { cc, type_, .. })| {
+        .filter_map(|(entry, cfg @ MentionsEntryConfig { cc, type_, .. })| {
             let relevant_file_paths: Vec<PathBuf> = match type_ {
                 MentionsEntryType::Filename => {
                     // Only mention matching paths.
@@ -98,10 +98,17 @@ pub(super) async fn parse_input(
                         .collect()
                 }
                 MentionsEntryType::Content => {
+                    let file_matcher = ModifiedPathMatcher::new(&cfg.trigger_files);
+                    let file_match = |f| file_matcher.is_match(Path::new(f));
                     // Only mentions byte-for-byte matching content inside the patch.
                     modified_files
                         .iter()
-                        .filter(|f| patch_adds(&f.patch, entry))
+                        .filter(|f| {
+                            patch_adds(&f.patch, entry)
+                                && (cfg.trigger_files.is_empty()
+                                    || file_match(&f.filename)
+                                    || f.previous_filename.as_ref().is_some_and(|p| file_match(p)))
+                        })
                         .map(|f| PathBuf::from(&f.filename))
                         .collect()
                 }