9/n: Find app root based on BuckTarget info only

Summary:
The previous buck project model tried to synthesise an application per directory.  To do this, it would attempt to identify the root directory, using various heuristics such as if there is a `src`, `tests` or `includes` directory.

For the new project model, we already receive absolute paths from the bxl query, and can choose the highest common path of all the included source files.

We have a fallback to the base directory of the BUCK file containing the target, but that should never be used.

Reviewed By: robertoaloi

Differential Revision: D65946488

fbshipit-source-id: 38e1338e5de5ea7fd5806818bf0e0f485236f499

crates/project_model/src/buck.rs

@@ -651,7 +651,7 @@ fn find_app_root_bxl(
         .chain(target.suite.iter());
 
     for path in paths {
-        if let Ok(path) = buck_path_to_abs_path(root, path) {
+        if let Ok(path) = AbsPathBuf::try_from(path.as_str()) {
             let parent = path.parent();
             if let Some(parent) = parent {
                 set.insert(parent.to_path_buf());
@@ -665,11 +665,7 @@ fn find_app_root_bxl(
         set.into_iter().reduce(|a, b| common_prefix(&a, &b))
     } else {
         for path in set {
-            if let Some(path) = examine_path(&path, dir_based_on_buck_file.as_path()) {
-                // We found an src/, test/, or include/ directory before the BUCK file,
-                // so we just return the parent of this directory.
-                return Some(path);
-            }
+            return Some(path);
         }
         // Otherwise, we just return the directory containing the BUCK file,
         Some(dir_based_on_buck_file)
@@ -1137,9 +1133,14 @@ mod tests {
     use expect_test::Expect;
 
     use super::*;
+    use crate::temp_dir::TempDir;
     use crate::test_fixture::FixtureWithProjectMeta;
     use crate::to_abs_path_buf;
 
+    fn as_absolute_string(dir: &TempDir, path: &str) -> String {
+        dir.path().join(path).to_string_lossy().to_string()
+    }
+
     #[test]
     fn test_find_app_root_src() {
         let spec = r#"
@@ -1152,15 +1153,15 @@ mod tests {
         let target = BuckTarget {
             name: "app_a".to_string(),
             suite: None,
-            srcs: vec!["cell//app_a/src/app.erl".to_string()],
+            srcs: vec![as_absolute_string(&dir, "app_a/src/app.erl")],
             includes: vec![],
             labels: FxHashSet::default(),
             deps: vec![],
             apps: vec![],
         };
 
         let actual = find_app_root_bxl(root, &target_name, &target);
-        let expected = Some(to_abs_path_buf(&dir.path().join("app_a").to_path_buf()).unwrap());
+        let expected = Some(to_abs_path_buf(&dir.path().join("app_a/src").to_path_buf()).unwrap());
         assert_eq!(expected, actual)
     }
 
@@ -1177,14 +1178,14 @@ mod tests {
             name: "app_a".to_string(),
             suite: None,
             srcs: vec![],
-            includes: vec!["cell//app_a/include/app.hrl".to_string()],
+            includes: vec![as_absolute_string(&dir, "app_a/include/app.hrl")],
             labels: FxHashSet::default(),
             deps: vec![],
             apps: vec![],
         };
 
         let actual = find_app_root_bxl(root, &target_name, &target);
-        let expected = Some(to_abs_path_buf(&dir.path().join("app_a")).unwrap());
+        let expected = Some(to_abs_path_buf(&dir.path().join("app_a/include")).unwrap());
         assert_eq!(expected, actual)
     }
 
@@ -1199,7 +1200,7 @@ mod tests {
         let target_name = "cell//app_a:app_a".to_string();
         let target = BuckTarget {
             name: "app_a".to_string(),
-            suite: Some("cell//app_a/test/app_SUITE.erl".to_string()),
+            suite: Some(as_absolute_string(&dir, "app_a/test/app_SUITE.erl")),
             srcs: vec![],
             includes: vec![],
             labels: FxHashSet::default(),
@@ -1208,7 +1209,7 @@ mod tests {
         };
 
         let actual = find_app_root_bxl(root, &target_name, &target);
-        let expected = Some(to_abs_path_buf(&dir.path().join("app_a")).unwrap());
+        let expected = Some(to_abs_path_buf(&dir.path().join("app_a/test")).unwrap());
         assert_eq!(expected, actual)
     }
 
@@ -1278,15 +1279,15 @@ mod tests {
         let target = BuckTarget {
             name: "app_a".to_string(),
             suite: None,
-            srcs: vec!["cell//app_a/sub/app.erl".to_string()],
-            includes: vec!["cell//app_a/sub/app.hrl".to_string()],
+            srcs: vec![as_absolute_string(&dir, "app_a/sub/app.erl")],
+            includes: vec![as_absolute_string(&dir, "app_a/sub/app.hrl")],
             labels: FxHashSet::default(),
             deps: vec![],
             apps: vec![],
         };
 
         let actual = find_app_root_bxl(root, &target_name, &target);
-        let expected = Some(to_abs_path_buf(&dir.path().join("app_a")).unwrap());
+        let expected = Some(to_abs_path_buf(&dir.path().join("app_a/sub")).unwrap());
         assert_eq!(expected, actual)
     }