move behind_master into check-commits

Signed-off-by: xizheyin <xizheyin@smail.nju.edu.cn>

Author: xizheyin

src/config.rs

@@ -49,7 +49,7 @@ pub(crate) struct Config {
     #[serde(alias = "canonicalize-issue-links")]
     pub(crate) issue_links: Option<IssueLinksConfig>,
     pub(crate) no_mentions: Option<NoMentionsConfig>,
-    pub(crate) pr_behind_commits: Option<PRBehindCommitsConfig>,
+    pub(crate) commits_behind_master: Option<CommitsBehindMasterConfig>,
 }
 
 #[derive(PartialEq, Eq, Debug, serde::Deserialize)]
@@ -431,7 +431,7 @@ pub(crate) struct NoMentionsConfig {}
 /// Configuration for PR behind commits checks
 #[derive(PartialEq, Eq, Debug, serde::Deserialize)]
 #[serde(deny_unknown_fields)]
-pub(crate) struct PRBehindCommitsConfig {
+pub(crate) struct CommitsBehindMasterConfig {
     /// The threshold of commits behind master to trigger a warning.
     /// Default is 100 if not specified.
     pub(crate) threshold: Option<u32>,
@@ -628,7 +628,7 @@ mod tests {
                 }),
                 issue_links: Some(IssueLinksConfig {}),
                 no_mentions: Some(NoMentionsConfig {}),
-                pr_behind_commits: None,
+                commits_behind_master: None,
             }
         );
     }
@@ -696,7 +696,7 @@ mod tests {
                 rendered_link: None,
                 issue_links: Some(IssueLinksConfig {}),
                 no_mentions: None,
-                pr_behind_commits: None,
+                commits_behind_master: None,
             }
         );
     }

src/handlers.rs

@@ -43,7 +43,6 @@ mod note;
 mod notification;
 mod notify_zulip;
 mod ping;
-mod pr_behind_commits;
 pub mod pr_tracking;
 mod prioritize;
 pub mod project_goals;
@@ -186,21 +185,6 @@ pub async fn handle(ctx: &Context, event: &Event) -> Vec<HandlerError> {
             );
         }
     }
-
-    if let Some(pr_behind_commits_config) = config
-        .as_ref()
-        .ok()
-        .and_then(|c| c.pr_behind_commits.as_ref())
-    {
-        if let Err(e) = pr_behind_commits::handle(ctx, event, pr_behind_commits_config).await {
-            log::error!(
-                "failed to process event {:?} with pr_behind_commits handler: {:?}",
-                event,
-                e
-            );
-        }
-    }
-
     errors
 }
 

src/handlers/check_commits.rs

@@ -10,6 +10,7 @@ use crate::{
 #[cfg(test)]
 use crate::github::GithubCommit;
 
+mod behind_master;
 mod issue_links;
 mod modified_submodule;
 mod no_mentions;
@@ -72,6 +73,14 @@ pub(super) async fn handle(ctx: &Context, event: &Event, config: &Config) -> any
         warnings.extend(issue_links::issue_links_in_commits(issue_links, &commits));
     }
 
+    // Check if PR is behind master branch by a significant number of commits
+    if let Some(commits_behind_master) = &config.commits_behind_master {
+        let threshold = commits_behind_master.threshold.unwrap_or(behind_master::DEFAULT_BEHIND_THRESHOLD);
+        if let Some(warning) = behind_master::behind_master(threshold, event, &ctx.github).await {
+            warnings.push(warning);
+        }
+    }
+
     handle_warnings(ctx, event, warnings).await
 }
 

src/handlers/check_commits/behind_master.rs

@@ -0,0 +1,73 @@
+use crate::github::{GithubClient, IssuesEvent};
+use tracing as log;
+
+/// Default threshold for the number of commits behind master to trigger a warning
+pub const DEFAULT_BEHIND_THRESHOLD: u32 = 100;
+
+/// Check if the PR is behind the main branch by a significant number of commits
+pub async fn behind_master(
+    threshold: u32,
+    event: &IssuesEvent,
+    client: &GithubClient,
+) -> Option<String> {
+    if !event.issue.is_pr() {
+        return None;
+    }
+
+    log::debug!("Checking if PR #{} is behind master", event.issue.number);
+
+    // Check how many commits the PR is behind master
+    let behind_by = match event.issue.commits_behind_base(client).await {
+        Ok(Some(count)) => count,
+        Ok(None) => {
+            log::warn!(
+                "Unable to determine commits behind base for PR #{}",
+                event.issue.number
+            );
+            return None;
+        }
+        Err(e) => {
+            log::error!(
+                "Error checking commits behind master for PR #{}: {}",
+                event.issue.number,
+                e
+            );
+            return None;
+        }
+    };
+
+
+    // If PR is behind by at least the threshold, generate a warning
+    if behind_by >= threshold {
+        // Get repository information for the message
+        let repo_info = match client.repository(&event.issue.repository().full_repo_name()).await {
+            Ok(repo) => repo,
+            Err(e) => {
+                log::error!(
+                    "Error getting repository info for PR #{}: {}",
+                    event.issue.number,
+                    e
+                );
+                return None;
+            }
+        };
+
+        log::info!(
+            "PR #{} is {} commits behind {} (threshold: {})",
+            event.issue.number,
+            behind_by,
+            repo_info.default_branch,
+            threshold
+        );
+
+        return Some(format!(
+            "This PR is {} commits behind the `{}` branch. \
+            It's recommended to update your branch according to the \
+            [Rustc Dev Guide](https://rustc-dev-guide.rust-lang.org/contributing.html#keeping-your-branch-up-to-date).",
+            behind_by,
+            repo_info.default_branch
+        ));
+    }
+
+    None
+}