Automatically fixup linked issues in subtree repository

src/config.rs

@@ -46,6 +46,7 @@ pub(crate) struct Config {
     pub(crate) merge_conflicts: Option<MergeConflictConfig>,
     pub(crate) bot_pull_requests: Option<BotPullRequests>,
     pub(crate) rendered_link: Option<RenderedLinkConfig>,
+    pub(crate) canonicalize_issue_links: Option<CanonicalizeIssueLinksConfig>,
 }
 
 #[derive(PartialEq, Eq, Debug, serde::Deserialize)]
@@ -414,6 +415,11 @@ pub(crate) struct RenderedLinkConfig {
     pub(crate) trigger_files: Vec<String>,
 }
 
+#[derive(PartialEq, Eq, Debug, serde::Deserialize)]
+#[serde(rename_all = "kebab-case")]
+#[serde(deny_unknown_fields)]
+pub(crate) struct CanonicalizeIssueLinksConfig {}
+
 fn get_cached_config(repo: &str) -> Option<Result<Arc<Config>, ConfigurationError>> {
     let cache = CONFIG_CACHE.read().unwrap();
     cache.get(repo).and_then(|(config, fetch_time)| {
@@ -535,6 +541,8 @@ mod tests {
 
             [shortcut]
 
+            [canonicalize-issue-links]
+
             [rendered-link]
             trigger-files = ["posts/"]
         "#;
@@ -598,7 +606,8 @@ mod tests {
                 bot_pull_requests: None,
                 rendered_link: Some(RenderedLinkConfig {
                     trigger_files: vec!["posts/".to_string()]
-                })
+                }),
+                canonicalize_issue_links: Some(CanonicalizeIssueLinksConfig {}),
             }
         );
     }
@@ -662,6 +671,7 @@ mod tests {
                 merge_conflicts: None,
                 bot_pull_requests: None,
                 rendered_link: None,
+                canonicalize_issue_links: None
             }
         );
     }

src/github.rs

@@ -522,7 +522,7 @@ impl IssueRepository {
         )
     }
 
-    fn full_repo_name(&self) -> String {
+    pub(crate) fn full_repo_name(&self) -> String {
         format!("{}/{}", self.organization, self.repository)
     }
 

src/handlers.rs

@@ -27,6 +27,7 @@ impl fmt::Display for HandlerError {
 mod assign;
 mod autolabel;
 mod bot_pull_requests;
+mod canonicalize_issue_links;
 mod check_commits;
 mod close;
 pub mod docs_update;
@@ -224,6 +225,7 @@ macro_rules! issue_handlers {
 issue_handlers! {
     assign,
     autolabel,
+    canonicalize_issue_links,
     major_change,
     mentions,
     no_merges,

src/handlers/canonicalize_issue_links.rs

@@ -0,0 +1,117 @@
+//! This handler is used to canonicalize linked GitHub issues into their long form
+//! so that when pulling subtree into the main repository we don't accidentaly
+//! close issues in the wrong repository.
+//!
+//! Example: `Fixes #123` (in rust-lang/clippy) would now become `Fixes rust-lang/clippy#123`
+
+use std::borrow::Cow;
+use std::sync::LazyLock;
+
+use regex::Regex;
+
+use crate::{
+    config::CanonicalizeIssueLinksConfig,
+    github::{IssuesAction, IssuesEvent},
+    handlers::Context,
+};
+
+// Taken from https://docs.github.com/en/issues/tracking-your-work-with-issues/using-issues/linking-a-pull-request-to-an-issue?quot#linking-a-pull-request-to-an-issue-using-a-keyword
+static LINKED_RE: LazyLock<Regex> = LazyLock::new(|| {
+    Regex::new("(?i)(?P<action>close|closes|closed|fix|fixes|fixed|resolve|resolves|resolved)(?P<spaces>:? +)(?P<issue>#[0-9]+)")
+        .unwrap()
+});
+
+pub(super) struct CanonicalizeIssueLinksInput {}
+
+pub(super) async fn parse_input(
+    _ctx: &Context,
+    event: &IssuesEvent,
+    config: Option<&CanonicalizeIssueLinksConfig>,
+) -> Result<Option<CanonicalizeIssueLinksInput>, String> {
+    if !event.issue.is_pr() {
+        return Ok(None);
+    }
+
+    if !matches!(
+        event.action,
+        IssuesAction::Opened | IssuesAction::Reopened | IssuesAction::Edited
+    ) {
+        return Ok(None);
+    }
+
+    // Require a `[canonicalize-issue-links]` configuration block to enable the handler.
+    if config.is_none() {
+        return Ok(None);
+    };
+
+    Ok(Some(CanonicalizeIssueLinksInput {}))
+}
+
+pub(super) async fn handle_input(
+    ctx: &Context,
+    _config: &CanonicalizeIssueLinksConfig,
+    e: &IssuesEvent,
+    _input: CanonicalizeIssueLinksInput,
+) -> anyhow::Result<()> {
+    let full_repo_name = e.issue.repository().full_repo_name();
+
+    let new_body = fix_linked_issues(&e.issue.body, full_repo_name.as_str());
+
+    if e.issue.body != new_body {
+        e.issue.edit_body(&ctx.github, &new_body).await?;
+    }
+
+    Ok(())
+}
+
+fn fix_linked_issues<'a>(body: &'a str, full_repo_name: &str) -> Cow<'a, str> {
+    let replace_by = format!("${{action}}${{spaces}}{full_repo_name}${{issue}}");
+    LINKED_RE.replace_all(body, replace_by)
+}
+
+#[test]
+fn fixed_body() {
+    let full_repo_name = "rust-lang/rust";
+
+    let body = r#"
+    This is a PR.
+
+    Fix #123
+    fixed #456
+    Fixes    #7895
+    Closes: #987
+    resolves:   #655
+    Resolves #00000 Closes #888
+    "#;
+
+    let fixed_body = r#"
+    This is a PR.
+
+    Fix rust-lang/rust#123
+    fixed rust-lang/rust#456
+    Fixes    rust-lang/rust#7895
+    Closes: rust-lang/rust#987
+    resolves:   rust-lang/rust#655
+    Resolves rust-lang/rust#00000 Closes rust-lang/rust#888
+    "#;
+
+    let new_body = fix_linked_issues(body, full_repo_name);
+    assert_eq!(new_body, fixed_body);
+}
+
+#[test]
+fn untouched_body() {
+    let full_repo_name = "rust-lang/rust";
+
+    let body = r#"
+    This is a PR.
+
+    Fix rust-lang#123
+    Fixesd #7895
+    Resolves #abgt
+    Resolves: #abgt
+    "#;
+
+    let new_body = fix_linked_issues(body, full_repo_name);
+    assert_eq!(new_body, body);
+}