Recognize conflicts involving deleted files

src/helpers/conflicts.rs

@@ -164,7 +164,12 @@ pub fn compare_pulls(
     // (https://github.com/TicClick/observatory/issues/17)
     let article_expr = regex::Regex::new(r"^(..|..-..)\.md$").unwrap();
     let article_filter = |p: &&unidiff::PatchedFile| -> bool {
-        let parts = std::path::Path::new(&p.target_file);
+        // For deleted files, target_file is /dev/null -- check source_file instead
+        let file_to_check = match p.target_file.contains("/dev/null") {
+            true => &p.source_file,
+            false => &p.target_file,
+        };
+        let parts = std::path::Path::new(file_to_check);
         if let Some(filename) = parts.file_name() {
             if let Some(filename_cstr) = filename.to_str() {
                 article_expr.is_match(filename_cstr)

src/helpers/conflicts/tests.rs

@@ -186,3 +186,107 @@ async fn new_translation_marked_as_incomplete() {
         )]
     );
 }
+
+#[tokio::test]
+async fn deleted_file_conflict_with_modification() {
+    let mut gh = test::GitHubServer::new().await;
+
+    let pulls = gh.pulls.entry("test/repo".into()).or_default();
+    let modifying_pull = crate::structs::PullRequest {
+        id: 1,
+        number: 1,
+        state: "open".to_string(),
+        title: "Modify file".to_string(),
+        user: crate::structs::Actor {
+            id: 1,
+            login: "user1".to_string(),
+        },
+        html_url: gh.url.pull_url("test/repo", 1),
+        created_at: chrono::Utc::now(),
+        updated_at: chrono::Utc::now(),
+        diff: Some(test::make_simple_diff(&["wiki/Article/en.md"])),
+        merged_at: None,
+        merged: false,
+    };
+    pulls.insert(1, modifying_pull.clone());
+
+    let deleting_pull = crate::structs::PullRequest {
+        id: 2,
+        number: 2,
+        state: "open".to_string(),
+        title: "Delete file".to_string(),
+        user: crate::structs::Actor {
+            id: 2,
+            login: "user2".to_string(),
+        },
+        html_url: gh.url.pull_url("test/repo", 2),
+        created_at: chrono::Utc::now(),
+        updated_at: chrono::Utc::now(),
+        diff: Some(test::make_deleted_file_diff(&["wiki/Article/en.md"])),
+        merged_at: None,
+        merged: false,
+    };
+    pulls.insert(2, deleting_pull.clone());
+
+    assert_eq!(
+        compare_pulls(&deleting_pull, &modifying_pull),
+        vec![Conflict::overlap(
+            2,
+            1,
+            gh.url.pull_url("test/repo", 1),
+            vec!["wiki/Article/en.md".to_string()],
+        )]
+    );
+}
+
+#[tokio::test]
+async fn deleted_file_conflict_with_addition() {
+    let mut gh = test::GitHubServer::new().await;
+
+    let pulls = gh.pulls.entry("test/repo".into()).or_default();
+    let adding_pull = crate::structs::PullRequest {
+        id: 1,
+        number: 1,
+        state: "open".to_string(),
+        title: "Add file".to_string(),
+        user: crate::structs::Actor {
+            id: 1,
+            login: "user1".to_string(),
+        },
+        html_url: gh.url.pull_url("test/repo", 1),
+        created_at: chrono::Utc::now(),
+        updated_at: chrono::Utc::now(),
+        diff: Some(test::make_added_file_diff(&["wiki/Article/de.md"])),
+        merged_at: None,
+        merged: false,
+    };
+    pulls.insert(1, adding_pull.clone());
+
+    let deleting_pull = crate::structs::PullRequest {
+        id: 2,
+        number: 2,
+        state: "open".to_string(),
+        title: "Delete file".to_string(),
+        user: crate::structs::Actor {
+            id: 2,
+            login: "user2".to_string(),
+        },
+        html_url: gh.url.pull_url("test/repo", 2),
+        created_at: chrono::Utc::now(),
+        updated_at: chrono::Utc::now(),
+        diff: Some(test::make_deleted_file_diff(&["wiki/Article/de.md"])),
+        merged_at: None,
+        merged: false,
+    };
+    pulls.insert(2, deleting_pull.clone());
+
+    assert_eq!(
+        compare_pulls(&deleting_pull, &adding_pull),
+        vec![Conflict::overlap(
+            2,
+            1,
+            gh.url.pull_url("test/repo", 1),
+            vec!["wiki/Article/de.md".to_string()],
+        )]
+    );
+}

src/test.rs

@@ -16,12 +16,12 @@ index 5483f282a0a..2c8c1482b97 100644
 --- a/{0}
 +++ b/{1}
 @@ -5,6 +5,7 @@
- 
+
  ## Test article
- 
+
 +<!-- test -->
  Do whatever you want.
- 
+
  That's it, that's the article."#,
                 file_name, file_name
             )
@@ -30,6 +30,62 @@ index 5483f282a0a..2c8c1482b97 100644
     unidiff::PatchSet::from_str(&diff.join("\n")).unwrap()
 }
 
+pub fn make_added_file_diff(file_names: &[&str]) -> unidiff::PatchSet {
+    let diff: Vec<String> = file_names
+        .iter()
+        .map(|file_name| {
+            format!(
+                r#"diff --git a/{0} b/{0}
+new file mode 100644
+index 0000000000..2c8c1482b97
+--- /dev/null
++++ b/{0}
+@@ -0,0 +1,11 @@
++---
++tags:
++  - test
++---
++
++## Test article
++
++Do whatever you want.
++
++That's it, that's the article."#,
+                file_name
+            )
+        })
+        .collect();
+    unidiff::PatchSet::from_str(&diff.join("\n")).unwrap()
+}
+
+pub fn make_deleted_file_diff(file_names: &[&str]) -> unidiff::PatchSet {
+    let diff: Vec<String> = file_names
+        .iter()
+        .map(|file_name| {
+            format!(
+                r#"diff --git a/{0} b/{0}
+deleted file mode 100644
+index 2c8c1482b97..0000000000
+--- a/{0}
++++ /dev/null
+@@ -1,11 +0,0 @@
+----
+-tags:
+-  - test
+----
+-
+-## Test article
+-
+-Do whatever you want.
+-
+-That's it, that's the article."#,
+                file_name
+            )
+        })
+        .collect();
+    unidiff::PatchSet::from_str(&diff.join("\n")).unwrap()
+}
+
 pub struct GitHubServer {
     pub server: mockito::ServerGuard,
     pub url: GitHub,