fix: preserve pip diagnostics when dependency downloads fail

aws_lambda_builders/workflows/python_pip/packager.py

@@ -55,8 +55,11 @@ def __init__(self, missing):
 class NoSuchPackageError(PackagerError):
     """Raised when a package name or version could not be found."""
 
-    def __init__(self, package_name):
-        super(NoSuchPackageError, self).__init__("Could not satisfy the requirement: %s" % package_name)
+    def __init__(self, package_name, pip_error=None):
+        message = "Could not satisfy the requirement: %s" % package_name
+        if pip_error:
+            message += "\npip output:\n" + pip_error
+        super(NoSuchPackageError, self).__init__(message)
 
 
 class PackageDownloadError(PackagerError):
@@ -926,7 +929,7 @@ def download_all_dependencies(self, requirements_filename, directory):
             match = re.search(("Could not find a version that satisfies the " "requirement (.+?) "), error)
             if match:
                 package_name = match.group(1)
-                raise NoSuchPackageError(str(package_name))
+                raise NoSuchPackageError(str(package_name), error)
             raise PackageDownloadError(error)
 
         # Extract local packages from pip output.

tests/unit/workflows/python_pip/test_packager.py

@@ -371,7 +371,23 @@ def test_raise_no_such_package_error(self, pip_factory):
         pip.add_return((1, b"", (b"Could not find a version that satisfies the " b"requirement BadPackageName ")))
         with pytest.raises(NoSuchPackageError) as einfo:
             runner.download_all_dependencies("requirements.txt", "directory")
-        assert str(einfo.value) == ("Could not satisfy the requirement: " "BadPackageName")
+        assert str(einfo.value) == (
+            "Could not satisfy the requirement: BadPackageName\npip output:\n"
+            "Could not find a version that satisfies the requirement BadPackageName "
+        )
+
+    def test_preserve_ssl_failure_with_no_matching_distribution(self, pip_factory):
+        pip, runner = pip_factory()
+        stderr = (
+            b"Could not fetch URL https://pypi.org/simple/example/: "
+            b"SSLError: certificate verify failed - skipping\n"
+            b"ERROR: Could not find a version that satisfies the requirement example (from versions: none)\n"
+            b"ERROR: No matching distribution found for example"
+        )
+        pip.add_return((1, b"", stderr))
+        with pytest.raises(NoSuchPackageError) as einfo:
+            runner.download_all_dependencies("requirements.txt", "directory")
+        assert stderr.decode() in str(einfo.value)
 
     def test_raise_other_unknown_error_during_downloads(self, pip_factory):
         pip, runner = pip_factory()