Respect the ignore directive in Buck

Summary: We need to respect this when figuring out what has changed (Buck generally doesn't see things marked ignore) and what files are on disk (again, it avoids the ones marked ignore).

Reviewed By: aniketmathur, shayne-fletcher

Differential Revision: D57542263

fbshipit-source-id: bb4c57b86b217cf94d0c56a95b4c5ca69fc65fd7

btd/src/buck/run.rs

@@ -125,9 +125,9 @@ impl Buck2 {
     pub fn does_package_exist(&mut self, cells: &CellInfo, x: &Package) -> anyhow::Result<bool> {
         let root = self.root()?;
         for build_file in cells.build_files(&x.cell())? {
-            if root
-                .join(cells.resolve(&x.join_path(build_file))?.as_str())
-                .exists()
+            let cell_path = x.join_path(build_file);
+            if !cells.is_ignored(&cell_path)
+                && root.join(cells.resolve(&cell_path)?.as_str()).exists()
             {
                 return Ok(true);
             }

btd/src/rerun.rs

@@ -46,26 +46,30 @@ pub fn rerun(
         return Ok(None);
     }
 
+    // Files which are ignored by Buck shouldn't be considered going forward,
+    // but are important to consider for the .buckconfig changes above
+    let changes = changes.filter_by_cell_path(|x| !cells.is_ignored(x));
+
     let mut res = HashMap::new();
     let all_packages = package_set(base);
     let add_present = |x: HashSet<_>| x.into_iter().map(|x| (x, PackageStatus::Present));
 
     // targets that are affected due to bzl/build file changes
-    let (changed, starlark_changes) = rerun_starlark(cells, base, changes)?;
+    let (changed, starlark_changes) = rerun_starlark(cells, base, &changes)?;
     res.extend(add_present(changed));
     // targets that are affected due to PACKAGE file changes
     res.extend(add_present(rerun_package_file(
-        changes,
+        &changes,
         &starlark_changes,
         &all_packages,
     )));
     // targets that are affected due to source file changes
-    res.extend(add_present(rerun_globs(changes, &all_packages)));
+    res.extend(add_present(rerun_globs(&changes, &all_packages)));
 
     // We extend with this set last, since it may insert PackageStatus::Unknown
     // which need to take precedence over the above.
     // if build file itself appears or disappears
-    res.extend(rerun_build_file_existence(cells, changes)?);
+    res.extend(rerun_build_file_existence(cells, &changes)?);
     Ok(Some(res))
 }