Auto merge of #9991 - Byron:fix-test-failure-due-to-echo-resolution, r=joshtriplett

Don't canonicalize executable path

Otherwise symbolic links may also accidentally be resolved which may lead to unexpected results in the case of 'coreutils', a binary that depends on the executable name being a symbolic link.

This means a path like /bin/echo being canonicalized to /bin/coreutils will loose all information about the desired functionality.

For example, test failures will occur if 'echo' is resolved that way and it's not trivial to find the cause of it in the provided error messages.  For example`doc_workspace_open_different_library_and_package_names` did fail for me on MacOS, Nix packages in PATH, but works with this patch.

With this patch, there is still the possibility that a path gets canonicalized for its relative path components, but still results in changing the name of the binary. I could imagine to check for binary name changes and panic if `coreutils` or `busybox` is encountered, which are known to fail without a symlink telling them which program to emulate.

Author: bors

crates/cargo-util/src/paths.rs

@@ -123,15 +123,13 @@ pub fn resolve_executable(exec: &Path) -> Result<PathBuf> {
         });
         for candidate in candidates {
             if candidate.is_file() {
-                // PATH may have a component like "." in it, so we still need to
-                // canonicalize.
-                return Ok(candidate.canonicalize()?);
+                return Ok(candidate);
             }
         }
 
         anyhow::bail!("no executable for `{}` found in PATH", exec.display())
     } else {
-        Ok(exec.canonicalize()?)
+        Ok(exec.into())
     }
 }