From 593587fbb154bcf1b78c896b1feef9a6f2b4a29f Mon Sep 17 00:00:00 2001
From: Andrew Klotz <aklotz@roblox.com>
Date: Tue, 21 Oct 2025 00:11:36 +0000
Subject: [PATCH] fix suggestion to include full path

This change returns a valid suggestion in the case of an invalid path to a BUCK file. This can come up from either making a typo in a target path or accidentially mismatching cases on a case-insensitive OS and then having a build run on a case-sensitive OS

Before, we matched on the closest parent directory then returned that as a suggested path, which can be confusing if `root//cat` is not a valid location:
```
dir `root//animals/pets/cats` does not exist. Did you mean `root//cat`?
```

After, we now return the full path to the matched directory allowing copy+paste of the suggestion to fix:
```
dir `root//animals/pets/cats` does not exist. Did you mean `root//animals/pets/cat`?
```

PS: I have no idea if the tests pass, the README says they can only run inside meta so this is just a guess
---
 app/buck2_common/src/file_ops/error.rs               |  5 ++++-
 tests/core/errors/test_errors.py                     |  2 ++
 .../package_listing/expected.golden.out              | 12 ++++++++++++
 3 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/app/buck2_common/src/file_ops/error.rs b/app/buck2_common/src/file_ops/error.rs
index d0d8f6aa12cc4..e2ad6a342892c 100644
--- a/app/buck2_common/src/file_ops/error.rs
+++ b/app/buck2_common/src/file_ops/error.rs
@@ -132,7 +132,10 @@ pub(super) fn extended_ignore_error<'a>(
                                 return Some(ReadDirError::DirectoryDoesNotExist {
                                     path: path.to_owned(),
                                     suggestion: DirectoryDoesNotExistSuggestion::Typo(
-                                        suggestion.to_owned(),
+                                        match parent.path().join_normalized(suggestion) {
+                                            Ok(p) => p.as_str().to_owned(),
+                                            Err(_) => suggestion.to_owned()
+                                        }
                                     ),
                                 });
                             }
diff --git a/tests/core/errors/test_errors.py b/tests/core/errors/test_errors.py
index f9d39f80dedbd..031217a88be69 100644
--- a/tests/core/errors/test_errors.py
+++ b/tests/core/errors/test_errors.py
@@ -61,6 +61,8 @@ async def test_package_listing_errors(buck: Buck) -> None:
         "//package_listing/data.file/subdir:target",
         # Missing directory due to typo
         "//package_listings:",
+        # Missing directory due to typo shows full path
+        "//package_listing/data.file:targets",
         # Missing directory due to being in the wrong cell
         "//something:",
     ]:
diff --git a/tests/core/errors/test_errors_data/package_listing/expected.golden.out b/tests/core/errors/test_errors_data/package_listing/expected.golden.out
index adb6845e7a071..a40246ca26c03 100644
--- a/tests/core/errors/test_errors_data/package_listing/expected.golden.out
+++ b/tests/core/errors/test_errors_data/package_listing/expected.golden.out
@@ -75,6 +75,18 @@ Caused by:
              ^-----------------------------^
        path `root//package_listing/data.file` is a file, not a directory
 
+Command failed:
+Error evaluating expression:
+    //package_listing/data.file:targets:
+    ^-----------------^
+
+
+Caused by:
+    package `root//package_listing/data.file:targets:` does not exist
+             ^--------------------^
+        dir `root//package_listing/data.file:targets` does not exist. Did you mean `root//package_listing/data.file:target`?
+
+
 
 
 Command failed: