utils/checkpackagelib: check for Upstream trailers

Implement a check-package check for an Upstream: trailer in patches
being applied to packages per a mailing list discussion [0].

No strict formatting checks are implemented for the contents within the
trailer as the needed level of detail will vary patch-to-patch.

Tested with: `./utils/docker-run python3 -m pytest utils/checkpackagelib`

[0] https://lists.buildroot.org/pipermail/buildroot/2023-March/666016.html

Signed-off-by: Vincent Fazio <vfazio@gmail.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

utils/checkpackagelib/lib_patch.py

@@ -61,3 +61,21 @@ class Sob(_CheckFunction):
             return ["{}:0: missing Signed-off-by in the header "
                     "({}#_format_and_licensing_of_the_package_patches)"
                     .format(self.filename, self.url_to_manual)]
+
+class Upstream(_CheckFunction):
+    UPSTREAM_ENTRY = re.compile(r"^Upstream: .*$")
+
+    def before(self):
+        self.found = False
+
+    def check_line(self, lineno, text):
+        if self.found:
+            return
+        if self.UPSTREAM_ENTRY.search(text):
+            self.found = True
+
+    def after(self):
+        if not self.found:
+            return ["{}:0: missing Upstream in the header "
+                    "({}#_additional_patch_documentation)"
+                    .format(self.filename, self.url_to_manual)]

utils/checkpackagelib/test_lib_patch.py

@@ -94,3 +94,25 @@ Sob = [
 def test_Sob(testname, filename, string, expected):
     warnings = util.check_file(m.Sob, filename, string)
     assert warnings == expected
+
+
+Upstream = [
+    ('good',
+     'patch',
+     'Upstream: https://some/amazing/patch/submission\n',
+     []),
+    ('empty',
+     'patch',
+     '',
+     [['patch:0: missing Upstream in the header (url#_additional_patch_documentation)']]),
+    ('bad',
+     'patch',
+     'Subject: [PATCH 24/105] text\n',
+     [['patch:0: missing Upstream in the header (url#_additional_patch_documentation)']]),
+    ]
+
+
+@pytest.mark.parametrize('testname,filename,string,expected', Upstream)
+def test_Upstream(testname, filename, string, expected):
+    warnings = util.check_file(m.Upstream, filename, string)
+    assert warnings == expected