Remove our custom diff parsing and prefer Github compare json API

src/github.rs

@@ -308,16 +308,7 @@ pub struct PullRequestDetails {
     /// handlers want to see PR changes, and getting the diff can be
     /// expensive.
     #[serde(skip)]
-    files_changed: tokio::sync::OnceCell<Vec<FileDiff>>,
-}
-
-/// Representation of a diff to a single file.
-#[derive(Debug)]
-pub struct FileDiff {
-    /// The full path of the file.
-    pub path: String,
-    /// The diff for the file.
-    pub diff: String,
+    compare: tokio::sync::OnceCell<GithubCompare>,
 }
 
 /// The return from GitHub compare API
@@ -329,13 +320,23 @@ pub struct GithubCompare {
     ///
     /// See <https://git-scm.com/docs/git-merge-base> for more details
     pub merge_base_commit: GithubCommit,
-    // FIXME: Also retrieve and use the files list (see our diff function)
+    /// List of file differences
+    pub files: Vec<FileDiff>,
+}
+
+/// Representation of a diff to a single file.
+#[derive(Debug, serde::Deserialize)]
+pub struct FileDiff {
+    /// The fullname path of the file.
+    pub filename: String,
+    /// The patch/diff for the file.
+    pub patch: String,
 }
 
 impl PullRequestDetails {
     pub fn new() -> PullRequestDetails {
         PullRequestDetails {
-            files_changed: tokio::sync::OnceCell::new(),
+            compare: tokio::sync::OnceCell::new(),
         }
     }
 }
@@ -977,6 +978,13 @@ impl Issue {
     ///
     /// Returns `None` if the issue is not a PR.
     pub async fn diff(&self, client: &GithubClient) -> anyhow::Result<Option<&[FileDiff]>> {
+        Ok(self.compare(client).await?.map(|c| c.files.as_ref()))
+    }
+
+    /// Returns the comparison of this event.
+    ///
+    /// Returns `None` if the issue is not a PR.
+    pub async fn compare(&self, client: &GithubClient) -> anyhow::Result<Option<&GithubCompare>> {
         let Some(pr) = &self.pull_request else {
             return Ok(None);
         };
@@ -986,41 +994,17 @@ impl Issue {
             return Ok(None);
         };
 
-        let diff = pr
-            .files_changed
+        let compare = pr
+            .compare
             .get_or_try_init::<anyhow::Error, _, _>(|| async move {
-                let url = format!(
+                let req = client.get(&format!(
                     "{}/compare/{before}...{after}",
                     self.repository().url(client)
-                );
-                let mut req = client.get(&url);
-                req = req.header("Accept", "application/vnd.github.v3.diff");
-                let (diff, _) = client
-                    .send_req(req)
-                    .await
-                    .with_context(|| format!("failed to fetch diff comparison for {url}"))?;
-                let body = String::from_utf8_lossy(&diff);
-                Ok(parse_diff(&body))
+                ));
+                Ok(client.json(req).await?)
             })
             .await?;
-        Ok(Some(diff))
-    }
-
-    /// Returns the comparison of this event.
-    ///
-    /// Returns `None` if the issue is not a PR.
-    pub async fn compare(&self, client: &GithubClient) -> anyhow::Result<Option<GithubCompare>> {
-        let (before, after) = if let (Some(base), Some(head)) = (&self.base, &self.head) {
-            (&base.sha, &head.sha)
-        } else {
-            return Ok(None);
-        };
-
-        let req = client.get(&format!(
-            "{}/compare/{before}...{after}",
-            self.repository().url(client)
-        ));
-        Ok(Some(client.json(req).await?))
+        Ok(Some(compare))
     }
 
     /// Returns the commits from this pull request (no commits are returned if this `Issue` is not
@@ -1264,31 +1248,6 @@ pub struct CommitBase {
     pub repo: Option<Repository>,
 }
 
-pub fn parse_diff(diff: &str) -> Vec<FileDiff> {
-    // This does not properly handle filenames with spaces.
-    let re = regex::Regex::new("(?m)^diff --git .* b/(.*)").unwrap();
-    let mut files: Vec<_> = re
-        .captures_iter(diff)
-        .map(|cap| {
-            let start = cap.get(0).unwrap().start();
-            let path = cap.get(1).unwrap().as_str().to_string();
-            (start, path)
-        })
-        .collect();
-    // Break the list up into (start, end) pairs starting from the "diff --git" line.
-    files.push((diff.len(), String::new()));
-    files
-        .windows(2)
-        .map(|w| {
-            let (start, end) = (&w[0], &w[1]);
-            FileDiff {
-                path: start.1.clone(),
-                diff: diff[start.0..end.0].to_string(),
-            }
-        })
-        .collect()
-}
-
 #[derive(Debug, serde::Deserialize)]
 pub struct IssueSearchResult {
     pub total_count: u64,
@@ -3221,71 +3180,4 @@ mod tests {
         };
         assert_eq!(x.to_string(), "Unknown labels: A-bootstrap, xxx");
     }
-
-    #[test]
-    fn extract_one_file() {
-        let input = r##"\
-diff --git a/triagebot.toml b/triagebot.toml
-index fb9cee43b2d..b484c25ea51 100644
---- a/triagebot.toml
-+++ b/triagebot.toml
-@@ -114,6 +114,15 @@ trigger_files = [
-        "src/tools/rustdoc-themes",
-    ]
-+[autolabel."T-compiler"]
-+trigger_files = [
-+    # Source code
-+    "compiler",
-+
-+    # Tests
-+    "src/test/ui",
-+]
-+
-    [notify-zulip."I-prioritize"]
-    zulip_stream = 245100 # #t-compiler/wg-prioritization/alerts
-    topic = "#{number} {title}"
-         "##;
-        let files: Vec<_> = parse_diff(input).into_iter().map(|d| d.path).collect();
-        assert_eq!(files, vec!["triagebot.toml".to_string()]);
-    }
-
-    #[test]
-    fn extract_several_files() {
-        let input = r##"\
-diff --git a/library/stdarch b/library/stdarch
-index b70ae88ef2a..cfba59fccd9 160000
---- a/library/stdarch
-+++ b/library/stdarch
-@@ -1 +1 @@
--Subproject commit b70ae88ef2a6c83acad0a1e83d5bd78f9655fd05
-+Subproject commit cfba59fccd90b3b52a614120834320f764ab08d1
-diff --git a/src/librustdoc/clean/types.rs b/src/librustdoc/clean/types.rs
-index 1fe4aa9023e..f0330f1e424 100644
---- a/src/librustdoc/clean/types.rs
-+++ b/src/librustdoc/clean/types.rs
-@@ -2322,3 +2322,4 @@ impl SubstParam {
-        if let Self::Lifetime(lt) = self { Some(lt) } else { None }
-    }
-}
-+
-diff --git a/src/librustdoc/core.rs b/src/librustdoc/core.rs
-index c58310947d2..3b0854d4a9b 100644
---- a/src/librustdoc/core.rs
-+++ b/src/librustdoc/core.rs
-@@ -591,3 +591,4 @@ fn from(idx: u32) -> Self {
-        ImplTraitParam::ParamIndex(idx)
-    }
-}
-+
-"##;
-        let files: Vec<_> = parse_diff(input).into_iter().map(|d| d.path).collect();
-        assert_eq!(
-            files,
-            vec![
-                "library/stdarch".to_string(),
-                "src/librustdoc/clean/types.rs".to_string(),
-                "src/librustdoc/core.rs".to_string(),
-            ]
-        )
-    }
 }

src/handlers/assign.rs

@@ -421,7 +421,7 @@ fn find_reviewers_from_diff(
                 .with_context(|| format!("owner file pattern `{owner_pattern}` is not valid"))?
                 .build()?;
             if ignore
-                .matched_path_or_any_parents(&file_diff.path, false)
+                .matched_path_or_any_parents(&file_diff.filename, false)
                 .is_ignore()
             {
                 let owner_len = owner_pattern.split('/').count();
@@ -442,7 +442,7 @@ fn find_reviewers_from_diff(
         }
 
         // Count the modified lines.
-        for line in file_diff.diff.lines() {
+        for line in file_diff.patch.lines() {
             if (!line.starts_with("+++") && line.starts_with('+'))
                 || (!line.starts_with("---") && line.starts_with('-'))
             {

src/handlers/assign/tests/tests_from_diff.rs

@@ -1,14 +1,12 @@
 //! Tests for `find_reviewers_from_diff`
 
 use super::super::*;
-use crate::github::parse_diff;
 use std::fmt::Write;
 
-fn test_from_diff(diff: &str, config: toml::Table, expected: &[&str]) {
-    let files = parse_diff(diff);
+fn test_from_diff(diff: &Vec<FileDiff>, config: toml::Table, expected: &[&str]) {
     let aconfig: AssignConfig = config.try_into().unwrap();
     assert_eq!(
-        find_reviewers_from_diff(&aconfig, &files).unwrap(),
+        find_reviewers_from_diff(&aconfig, &*diff).unwrap(),
         expected.iter().map(|x| x.to_string()).collect::<Vec<_>>()
     );
 }
@@ -18,27 +16,24 @@ fn test_from_diff(diff: &str, config: toml::Table, expected: &[&str]) {
 /// `paths` should be a slice of `(path, added, removed)` tuples where `added`
 /// is the number of lines added, and `removed` is the number of lines
 /// removed.
-fn make_fake_diff(paths: &[(&str, u32, u32)]) -> String {
+fn make_fake_diff(paths: &[(&str, u32, u32)]) -> Vec<FileDiff> {
     // This isn't a properly structured diff, but it has approximately enough
     // information for what is needed for testing.
     paths
         .iter()
         .map(|(path, added, removed)| {
-            let mut diff = format!(
-                "diff --git a/{path} b/{path}\n\
-                 index 1677422122e..1108c1f4d4c 100644\n\
-                 --- a/{path}\n\
-                 +++ b/{path}\n\
-                 @@ -0,0 +1 @@\n"
-            );
+            let mut diff = "@@ -0,0 +1 @@ ".to_string();
             for n in 0..*added {
                 writeln!(diff, "+Added line {n}").unwrap();
             }
             for n in 0..*removed {
                 writeln!(diff, "-Removed line {n}").unwrap();
             }
             diff.push('\n');
-            diff
+            FileDiff {
+                filename: path.to_string(),
+                patch: diff,
+            }
         })
         .collect()
 }
@@ -61,16 +56,15 @@ fn from_diff_submodule() {
         [owners]
         "/src" = ["user1", "user2"]
     );
-    let diff = "\
-        diff --git a/src/jemalloc b/src/jemalloc\n\
-        index 2dba541..b001609 160000\n\
-        --- a/src/jemalloc\n\
-        +++ b/src/jemalloc\n\
-        @@ -1 +1 @@\n\
-        -Subproject commit 2dba541881fb8e35246d653bbe2e7c7088777a4a\n\
-        +Subproject commit b001609960ca33047e5cbc5a231c1e24b6041d4b\n\
-    ";
-    test_from_diff(diff, config, &["user1", "user2"]);
+    let diff = vec![FileDiff {
+        filename: "src/jemalloc".to_string(),
+        patch: "@@ -1 +1 @@\n\
+            -Subproject commit 2dba541881fb8e35246d653bbe2e7c7088777a4a\n\
+            +Subproject commit b001609960ca33047e5cbc5a231c1e24b6041d4b\n\
+        "
+        .to_string(),
+    }];
+    test_from_diff(&diff, config, &["user1", "user2"]);
 }
 
 #[test]
@@ -131,9 +125,12 @@ fn empty_file_still_counts() {
         "/compiler" = ["compiler"]
         "/compiler/rustc_parse" = ["parser"]
     );
-    let diff = "diff --git a/compiler/rustc_parse/src/foo.rs b/compiler/rustc_parse/src/foo.rs\n\
-                new file mode 100644\n\
-                index 0000000..e69de29\n";
+    let diff = vec![FileDiff {
+        filename: "compiler/rustc_parse/src/foo.rs".to_string(),
+        patch: "new file mode 100644\n\
+                index 0000000..e69de29\n"
+            .to_string(),
+    }];
     test_from_diff(&diff, config, &["parser"]);
 }
 

src/handlers/autolabel.rs

@@ -84,11 +84,11 @@ pub(super) async fn parse_input(
                     // This a PR with modified files.
 
                     // Add the matching labels for the modified files paths
-                    if cfg
-                        .trigger_files
-                        .iter()
-                        .any(|f| files.iter().any(|file_diff| file_diff.path.starts_with(f)))
-                    {
+                    if cfg.trigger_files.iter().any(|f| {
+                        files
+                            .iter()
+                            .any(|file_diff| file_diff.filename.starts_with(f))
+                    }) {
                         autolabels.push(Label {
                             name: label.to_owned(),
                         });

src/handlers/check_commits.rs

@@ -52,19 +52,14 @@ pub(super) async fn handle(ctx: &Context, event: &Event, config: &Config) -> any
         return Ok(());
     }
 
-    let Some(diff) = event.issue.diff(&ctx.github).await? else {
-        bail!(
-            "expected issue {} to be a PR, but the diff could not be determined",
-            event.issue.number
-        )
-    };
     let Some(compare) = event.issue.compare(&ctx.github).await? else {
         bail!(
             "expected issue {} to be a PR, but the compare could not be determined",
             event.issue.number
         )
     };
     let commits = event.issue.commits(&ctx.github).await?;
+    let diff = &compare.files;
 
     let mut warnings = Vec::new();
     let mut labels = Vec::new();

src/handlers/check_commits/modified_submodule.rs

@@ -5,7 +5,7 @@ const SUBMODULE_WARNING_MSG: &str = "Some commits in this PR modify **submodules
 /// Returns a message if the PR modifies a git submodule.
 pub(super) fn modifies_submodule(diff: &[FileDiff]) -> Option<String> {
     let re = regex::Regex::new(r"\+Subproject\scommit\s").unwrap();
-    if diff.iter().any(|fd| re.is_match(&fd.diff)) {
+    if diff.iter().any(|fd| re.is_match(&fd.patch)) {
         Some(SUBMODULE_WARNING_MSG.to_string())
     } else {
         None

src/handlers/mentions.rs

@@ -59,7 +59,7 @@ pub(super) async fn parse_input(
         })
         .unwrap_or_default()
     {
-        let file_paths: Vec<_> = files.iter().map(|fd| Path::new(&fd.path)).collect();
+        let file_paths: Vec<_> = files.iter().map(|fd| Path::new(&fd.filename)).collect();
         let to_mention: Vec<_> = config
             .paths
             .iter()

src/handlers/milestone_prs.rs

@@ -65,10 +65,10 @@ pub(super) async fn handle(ctx: &Context, event: &Event) -> anyhow::Result<()> {
 
     let files = e.issue.diff(&ctx.github).await?;
     if let Some(files) = files {
-        if let Some(cargo) = files.iter().find(|fd| fd.path == "src/tools/cargo") {
+        if let Some(cargo) = files.iter().find(|fd| fd.filename == "src/tools/cargo") {
             // The webhook timeout of 10 seconds can be too short, so process in
             // the background.
-            let diff = cargo.diff.clone();
+            let diff = cargo.patch.clone();
             tokio::task::spawn(async move {
                 let gh = GithubClient::new_from_env();
                 if let Err(e) = milestone_cargo(&gh, &version, &diff).await {

src/handlers/validate_config.rs

@@ -34,7 +34,7 @@ pub(super) async fn parse_input(
             return Ok(None);
         }
     };
-    if !diff.iter().any(|diff| diff.path == CONFIG_FILE_NAME) {
+    if !diff.iter().any(|diff| diff.filename == CONFIG_FILE_NAME) {
         return Ok(None);
     }