fix: show stderror as well on patching errors

In case patching fails, we need to capture stderror as well, as git
emits the reason only on stderr.

While fixing this, we parameterize the PatchApplyError to print the vcs
data in a uniform format.

Fixes: 5e4da50 ("repos: restore error handling of patch apply")
Signed-off-by: Felix Moessbauer <[email protected]>
Signed-off-by: Jan Kiszka <[email protected]>

Author: fmoessbauer

kas/repos.py

@@ -72,6 +72,14 @@ class PatchApplyError(KasUserError):
     """
     The provided patch file could not be applied
     """
+    def __init__(self, msg, cmd=None, out=None, err=None):
+        if cmd:
+            msg += '\nvcs command: ' + ' '.join(cmd)
+        if out and out.strip():
+            msg += f'\nvcs output:\n{out.strip()}'
+        if err and err.strip():
+            msg += f'\nvcs error:\n{err.strip()}'
+        super().__init__(msg)
 
 
 class Repo:
@@ -500,24 +508,24 @@ async def apply_patches_async(self):
 
         for (path, patch_id) in my_patches:
             cmd = self.apply_patches_file_cmd(path)
-            (retc, output) = await run_cmd_async(
-                cmd, cwd=self.path, fail=False)
+            (retc, out, err) = await run_cmd_async(
+                cmd, cwd=self.path, fail=False, capture_stderr=True)
             if retc:
                 raise PatchApplyError(
-                    'Could not apply patch. Please fix repos and patches. '
-                    f'(patch path: {path}, repo: {self.name}, patch '
-                    f'entry: {patch_id}, vcs output: {output})')
+                    'Could not apply patch. Please fix repos and patches:\n'
+                    f'patch path: {path}, repo: {self.name}, patch '
+                    f'entry: {patch_id}', cmd, out, err)
 
             logging.info('Patch applied. '
                          '(patch path: %s, repo: %s, patch entry: %s)',
                          path, self.name, patch_id)
 
             cmd = self.add_cmd()
-            (retc, output) = await run_cmd_async(
-                cmd, cwd=self.path, fail=False)
+            (retc, out, err) = await run_cmd_async(
+                cmd, cwd=self.path, fail=False, capture_stderr=True)
             if retc:
-                raise PatchApplyError('Could not add patched files. repo: '
-                                      f'{self.name}, vcs output: {output})')
+                raise PatchApplyError('Could not add patched files: repo: '
+                                      f'{self.name}', cmd, out, err)
 
             timestamp = self.get_patch_timestamp(path)
             if not timestamp:
@@ -529,11 +537,11 @@ async def apply_patches_async(self):
             msg = f'kas: {patch_id}\n\npatch {path} applied by kas'
             cmd = self.commit_cmd(env, 'kas <[email protected]>', msg,
                                   timestamp)
-            (retc, output) = await run_cmd_async(
-                cmd, cwd=self.path, env=env, fail=False)
+            (retc, out, err) = await run_cmd_async(
+                cmd, cwd=self.path, env=env, fail=False, capture_stderr=True)
             if retc:
                 raise PatchApplyError('Could not commit patch changes. repo: '
-                                      f'{self.name}, vcs output: {output})')
+                                      f'{self.name}', cmd, out, err)
 
         return 0