Refactor errors for sync command

Per discussion in go/repo-error-update updated aggregated and exit
errors for sync command.

Aggregated errors are errors that result in eventual command failure.
Exit errors are errors that result in immediate command failure.

Also updated main.py to log aggregated and exit errors to git sessions
log

Bug: b/293344017
Change-Id: I77a21f14da32fe2e68c16841feb22de72e86a251
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/379614
Reviewed-by: Aravind Vasudevan <aravindvasudev@google.com>
Tested-by: Jason Chang <jasonnc@google.com>
Commit-Queue: Jason Chang <jasonnc@google.com>

main.py

@@ -30,6 +30,7 @@ import sys
 import textwrap
 import time
 import urllib.request
+import json
 
 try:
     import kerberos
@@ -50,10 +51,12 @@ from editor import Editor
 from error import DownloadError
 from error import InvalidProjectGroupsError
 from error import ManifestInvalidRevisionError
-from error import ManifestParseError
 from error import NoManifestException
 from error import NoSuchProjectError
 from error import RepoChangedException
+from error import RepoExitError
+from error import RepoUnhandledExceptionError
+from error import RepoError
 import gitc_utils
 from manifest_xml import GitcClient, RepoClient
 from pager import RunPager, TerminatePager
@@ -97,6 +100,7 @@ else:
         )
 
 KEYBOARD_INTERRUPT_EXIT = 128 + signal.SIGINT
+MAX_PRINT_ERRORS = 5
 
 global_options = optparse.OptionParser(
     usage="repo [-p|--paginate|--no-pager] COMMAND [ARGS]",
@@ -422,10 +426,33 @@ class _Repo(object):
             """
             try:
                 execute_command_helper()
-            except (KeyboardInterrupt, SystemExit, Exception) as e:
+            except (
+                KeyboardInterrupt,
+                SystemExit,
+                Exception,
+                RepoExitError,
+            ) as e:
                 ok = isinstance(e, SystemExit) and not e.code
+                exception_name = type(e).__name__
+                if isinstance(e, RepoUnhandledExceptionError):
+                    exception_name = type(e.error).__name__
+                if isinstance(e, RepoExitError):
+                    aggregated_errors = e.aggregate_errors or []
+                    for error in aggregated_errors:
+                        project = None
+                        if isinstance(error, RepoError):
+                            project = error.project
+                        error_info = json.dumps(
+                            {
+                                "ErrorType": type(error).__name__,
+                                "Project": project,
+                                "Message": str(error),
+                            }
+                        )
+                        git_trace2_event_log.ErrorEvent(
+                            f"AggregateExitError:{error_info}"
+                        )
                 if not ok:
-                    exception_name = type(e).__name__
                     git_trace2_event_log.ErrorEvent(
                         f"RepoExitError:{exception_name}"
                     )
@@ -447,13 +474,13 @@ class _Repo(object):
                     "error: manifest missing or unreadable -- please run init",
                     file=sys.stderr,
                 )
-            result = 1
+            result = e.exit_code
         except NoSuchProjectError as e:
             if e.name:
                 print("error: project %s not found" % e.name, file=sys.stderr)
             else:
                 print("error: no project in current directory", file=sys.stderr)
-            result = 1
+            result = e.exit_code
         except InvalidProjectGroupsError as e:
             if e.name:
                 print(
@@ -467,7 +494,7 @@ class _Repo(object):
                     "the current directory",
                     file=sys.stderr,
                 )
-            result = 1
+            result = e.exit_code
         except SystemExit as e:
             if e.code:
                 result = e.code
@@ -475,6 +502,9 @@ class _Repo(object):
         except KeyboardInterrupt:
             result = KEYBOARD_INTERRUPT_EXIT
             raise
+        except RepoExitError as e:
+            result = e.exit_code
+            raise
         except Exception:
             result = 1
             raise
@@ -841,12 +871,20 @@ def _Main(argv):
             SetTraceToStderr()
 
         result = repo._Run(name, gopts, argv) or 0
+    except RepoExitError as e:
+        exception_name = type(e).__name__
+        result = e.exit_code
+        print("fatal: %s" % e, file=sys.stderr)
+        if e.aggregate_errors:
+            print(f"{exception_name} Aggregate Errors")
+            for err in e.aggregate_errors[:MAX_PRINT_ERRORS]:
+                print(err)
+        if len(e.aggregate_errors) > MAX_PRINT_ERRORS:
+            diff = len(e.aggregate_errors) - MAX_PRINT_ERRORS
+            print(f"+{diff} additional errors ...")
     except KeyboardInterrupt:
         print("aborted by user", file=sys.stderr)
         result = KEYBOARD_INTERRUPT_EXIT
-    except ManifestParseError as mpe:
-        print("fatal: %s" % mpe, file=sys.stderr)
-        result = 1
     except RepoChangedException as rce:
         # If repo changed, re-exec ourselves.
         #