From b531faf77541637815b44821d69475ffda567769 Mon Sep 17 00:00:00 2001
From: Zalathar <Zalathar@users.noreply.github.com>
Date: Sat, 8 Aug 2026 17:45:44 +1000
Subject: [PATCH] Simplify absolute path handling

The existing code takes a command-line argument (that might not even be a
path), glues it to the repository path, makes it absolute relative to the
working directory, then tries to strip the repository path off again.

That all seems needlessly complicated.

The new approach is much simpler: If an argument is an absolute path that
exists, try to strip the repository path from it, or otherwise change nothing.
That should hopefully give the same results in every useful case.
---
 src/bootstrap/src/core/builder/cli_paths.rs | 53 ++++++++++-----------
 1 file changed, 25 insertions(+), 28 deletions(-)

diff --git a/src/bootstrap/src/core/builder/cli_paths.rs b/src/bootstrap/src/core/builder/cli_paths.rs
index 29daf64db49c7..5efbea64463fe 100644
--- a/src/bootstrap/src/core/builder/cli_paths.rs
+++ b/src/bootstrap/src/core/builder/cli_paths.rs
@@ -76,37 +76,34 @@ pub(crate) fn match_paths_to_steps_and_run(
         }
     }
 
-    // Attempt to resolve paths to be relative to the builder source directory.
-    let mut paths: Vec<PathBuf> = paths
+    // Command-line paths are interpreted relative to the repository root
+    // (not the current working directory).
+    //
+    // If the user or shell passed an absolute path, try to strip off the
+    // repository root, to match the paths registered by command-line steps.
+    //
+    // E.g. `/home/ferris/rust/tests/ui/asm/cfg.rs` => `tests/ui/asm/cfg.rs`
+    let mut paths = paths
         .iter()
-        .map(|original_path| {
-            let mut path = original_path.clone();
-
-            // Someone could run `x <cmd> <path>` from a different repository than the source
-            // directory.
-            // In that case, we should not try to resolve the paths relative to the working
-            // directory, but rather relative to the source directory.
-            // So we forcefully "relocate" the path to the source directory here.
-            if !path.is_absolute() {
-                path = builder.src.join(path);
-            }
-
-            // If the path does not exist, it may represent the name of a Step, such as `tidy` in `x test tidy`
-            if !path.exists() {
-                // Use the original path here
-                return original_path.clone();
-            }
-
-            // Make the path absolute, strip the prefix, and convert to a PathBuf.
-            match std::path::absolute(&path) {
-                Ok(p) => p.strip_prefix(&builder.src).unwrap_or(&p).to_path_buf(),
-                Err(e) => {
-                    eprintln!("ERROR: {e:?}");
-                    panic!("Due to the above error, failed to resolve path: {path:?}");
-                }
+        .map(|path| {
+            if path.is_absolute()
+                && path.exists()
+                && let Ok(relative) = path.strip_prefix(&builder.src)
+            {
+                relative
+            } else {
+                path
             }
         })
-        .collect();
+        .map(|p| p.to_owned())
+        .collect::<Vec<_>>();
+
+    // If any absolute paths couldn't be made relative, stop now and report them.
+    let bad_abs_paths = paths.iter().filter(|path| path.is_absolute()).collect::<Vec<_>>();
+    if !bad_abs_paths.is_empty() {
+        eprintln!("ERROR: failed to resolve absolute paths: {bad_abs_paths:#?}");
+        crate::exit!(1);
+    }
 
     // Handle all test suite paths.
     // (This is separate from the loop below to avoid having to handle multiple paths in `is_suite_path` somehow.)