[PATCH 3/4] oe/path: canonicalize('') should return '' rather than the cwd

[Trevor Woerner <twoerner@gmail.com>]

canonicalize() splits its input on the separator and runs each token
through os.path.realpath(). os.path.realpath('') returns the current
working directory, so canonicalize('') and canonicalize(None) wrongly
produced the cwd instead of an empty string, and a stray separator (for
example "a,,b") injected a spurious cwd entry into the result.

Skip empty tokens alongside the existing unexpanded-variable skip so only
real paths are canonicalized.

AI-Generated: codex/claude-opus 4.8 (xhigh)
Signed-off-by: Trevor Woerner <twoerner@gmail.com>
---
 meta/lib/oe/path.py | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/meta/lib/oe/path.py b/meta/lib/oe/path.py
index 44a9ff9d0757..7255d99bc2f7 100644
--- a/meta/lib/oe/path.py
+++ b/meta/lib/oe/path.py
@@ -356,7 +356,11 @@ def canonicalize(paths, sep=','):
     # prefixes in sting compares later on, where the slashes then are important.
     canonical_paths = []
     for path in (paths or '').split(sep):
-        if '$' not in path:
+        # Skip empty tokens as well as unexpanded bitbake variables: an
+        # empty path would otherwise reach os.path.realpath(''), which
+        # returns the current working directory, so canonicalize('') or
+        # canonicalize(None) would wrongly produce the cwd instead of ''.
+        if path and '$' not in path:
             trailing_slash = path.endswith('/') and '/' or ''
             canonical_paths.append(os.path.realpath(path) + trailing_slash)
 
-- 
2.50.0.173.g8b6f19ccfc3a