Document _cargo_toml

rust2rpm/inspector.py

@@ -16,20 +16,37 @@ def _get_binaries(cargo_toml):
 
 def _cargo_toml(source_path, path, exclude_vendor=True):
     """Find a Cargo.toml related with a binary."""
-    # If path is aready a Cargo.toml file, we are done
-    if path.endswith('Cargo.toml'):
+    # Finding the Cargo.toml is a bit tricky, and the general idea is
+    # like this:
+    #
+    #   - `source_path`: is set but the dependecy generator call
+    #     (cargo_bundled.attr) to point to `%{_builddir}`, so where
+    #     the sources are (`.../rpmbuild/BUILD`)
+    #
+    #   - `path`: can point to an executable when called by
+    #     cargo_bundler.attr, that lives in `%{_buildroot}`, for
+    #     example `.../rpmbuild/BUILDROOT/<PKGNAME>/usr/bin/<BINNAME>`
+    #
+    #   - `path`: can also point to a Cargo.toml when called from
+    #     command line
+    #
+    #   - If `path` is a binary, we search the Cargo.toml from
+    #     `source_path` that generates this specific binary
+
+    # If path is already a Cargo.toml file, we are done
+    binary_or_cargo_toml = os.path.basename(path)
+    if binary_or_cargo_toml == 'Cargo.toml':
         return os.path.join(source_path, path)
 
-    binary = os.path.basename(path)
     cargo_tomls = glob.glob(os.path.join(source_path, '**/Cargo.toml'),
                             recursive=True)
     for cargo_toml in cargo_tomls:
         if exclude_vendor and 'vendor' in cargo_toml.split(os.sep):
             continue
-
-        if binary in _get_binaries(cargo_toml):
+        if binary_or_cargo_toml in _get_binaries(cargo_toml):
             return cargo_toml
-    raise Exception(f'Cargo.toml not found for binary {binary}')
+
+    raise Exception(f'Cargo.toml not found for binary {binary_or_cargo_toml}')
 
 
 def main():