Raise RepoExitError in place of sys.exit

Bug: b/293344017
Change-Id: Icae4932b00e4068cba502a5ab4a0274fd7854d9d
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/382214
Reviewed-by: Gavin Mak <gavinmak@google.com>
Tested-by: Jason Chang <jasonnc@google.com>
Reviewed-by: Aravind Vasudevan <aravindvasudev@google.com>
Commit-Queue: Jason Chang <jasonnc@google.com>

7 files changed, 201 insertions, 87 deletions

diff --git a/subcmds/checkout.py b/subcmds/checkout.py
index 6448518f..033fd349 100644
--- a/subcmds/checkout.py
+++ b/subcmds/checkout.py
@@ -15,8 +15,26 @@
 import functools
 import sys
 
+from typing import NamedTuple
 from command import Command, DEFAULT_LOCAL_JOBS
 from progress import Progress
+from project import Project
+from error import GitError, RepoExitError
+
+
+class CheckoutBranchResult(NamedTuple):
+    # Whether the Project is on the branch (i.e. branch exists and no errors)
+    result: bool
+    project: Project
+    error: Exception
+
+
+class CheckoutCommandError(RepoExitError):
+    """Exception thrown when checkout command fails."""
+
+
+class MissingBranchError(RepoExitError):
+    """Exception thrown when no project has specified branch."""
 
 
 class Checkout(Command):
@@ -41,23 +59,30 @@ The command is equivalent to:
 
     def _ExecuteOne(self, nb, project):
         """Checkout one project."""
-        return (project.CheckoutBranch(nb), project)
+        error = None
+        result = None
+        try:
+            result = project.CheckoutBranch(nb)
+        except GitError as e:
+            error = e
+        return CheckoutBranchResult(result, project, error)
 
     def Execute(self, opt, args):
         nb = args[0]
         err = []
+        err_projects = []
         success = []
         all_projects = self.GetProjects(
             args[1:], all_manifests=not opt.this_manifest_only
         )
 
         def _ProcessResults(_pool, pm, results):
-            for status, project in results:
-                if status is not None:
-                    if status:
-                        success.append(project)
-                    else:
-                        err.append(project)
+            for result in results:
+                if result.error is not None:
+                    err.append(result.error)
+                    err_projects.append(result.project)
+                elif result.result:
+                    success.append(result.project)
                 pm.update(msg="")
 
         self.ExecuteInParallel(
@@ -70,13 +95,14 @@ The command is equivalent to:
             ),
         )
 
-        if err:
-            for p in err:
+        if err_projects:
+            for p in err_projects:
                 print(
                     "error: %s/: cannot checkout %s" % (p.relpath, nb),
                     file=sys.stderr,
                 )
-            sys.exit(1)
+            raise CheckoutCommandError(aggregate_errors=err)
         elif not success:
-            print("error: no project has branch %s" % nb, file=sys.stderr)
-            sys.exit(1)
+            msg = f"error: no project has branch {nb}"
+            print(msg, file=sys.stderr)
+            raise MissingBranchError(msg)
diff --git a/subcmds/cherry_pick.py b/subcmds/cherry_pick.py
index 4cfb8c88..7a4dd09e 100644
--- a/subcmds/cherry_pick.py
+++ b/subcmds/cherry_pick.py
@@ -16,6 +16,7 @@ import re
 import sys
 from command import Command
 from git_command import GitCommand
+from error import GitError
 
 CHANGE_ID_RE = re.compile(r"^\s*Change-Id: I([0-9a-f]{40})\s*$")
 
@@ -44,18 +45,31 @@ change id will be added.
             ["rev-parse", "--verify", reference],
             capture_stdout=True,
             capture_stderr=True,
+            verify_command=True,
         )
-        if p.Wait() != 0:
+        try:
+            p.Wait()
+        except GitError:
             print(p.stderr, file=sys.stderr)
-            sys.exit(1)
+            raise
+
         sha1 = p.stdout.strip()
 
-        p = GitCommand(None, ["cat-file", "commit", sha1], capture_stdout=True)
-        if p.Wait() != 0:
+        p = GitCommand(
+            None,
+            ["cat-file", "commit", sha1],
+            capture_stdout=True,
+            verify_command=True,
+        )
+
+        try:
+            p.Wait()
+        except GitError:
             print(
                 "error: Failed to retrieve old commit message", file=sys.stderr
             )
-            sys.exit(1)
+            raise
+
         old_msg = self._StripHeader(p.stdout)
 
         p = GitCommand(
@@ -63,37 +77,47 @@ change id will be added.
             ["cherry-pick", sha1],
             capture_stdout=True,
             capture_stderr=True,
+            verify_command=True,
         )
-        status = p.Wait()
+
+        try:
+            p.Wait()
+        except GitError as e:
+            print(str(e))
+            print(
+                "NOTE: When committing (please see above) and editing the "
+                "commit message, please remove the old Change-Id-line and "
+                "add:"
+            )
+            print(self._GetReference(sha1), file=sys.stderr)
+            print(file=sys.stderr)
+            raise
 
         if p.stdout:
             print(p.stdout.strip(), file=sys.stdout)
         if p.stderr:
             print(p.stderr.strip(), file=sys.stderr)
 
-        if status == 0:
-            # The cherry-pick was applied correctly. We just need to edit the
-            # commit message.
-            new_msg = self._Reformat(old_msg, sha1)
-
-            p = GitCommand(
-                None,
-                ["commit", "--amend", "-F", "-"],
-                input=new_msg,
-                capture_stdout=True,
-                capture_stderr=True,
-            )
-            if p.Wait() != 0:
-                print("error: Failed to update commit message", file=sys.stderr)
-                sys.exit(1)
+        # The cherry-pick was applied correctly. We just need to edit
+        # the commit message.
+        new_msg = self._Reformat(old_msg, sha1)
 
-        else:
+        p = GitCommand(
+            None,
+            ["commit", "--amend", "-F", "-"],
+            input=new_msg,
+            capture_stdout=True,
+            capture_stderr=True,
+            verify_command=True,
+        )
+        try:
+            p.Wait()
+        except GitError:
             print(
-                "NOTE: When committing (please see above) and editing the "
-                "commit message, please remove the old Change-Id-line and add:"
+                "error: Failed to update commit message",
+                file=sys.stderr,
             )
-            print(self._GetReference(sha1), file=sys.stderr)
-            print(file=sys.stderr)
+            raise
 
     def _IsChangeId(self, line):
         return CHANGE_ID_RE.match(line)
diff --git a/subcmds/download.py b/subcmds/download.py
index 475c0bc2..18e555be 100644
--- a/subcmds/download.py
+++ b/subcmds/download.py
@@ -16,11 +16,15 @@ import re
 import sys
 
 from command import Command
-from error import GitError, NoSuchProjectError
+from error import GitError, NoSuchProjectError, RepoExitError
 
 CHANGE_RE = re.compile(r"^([1-9][0-9]*)(?:[/\.-]([1-9][0-9]*))?$")
 
 
+class DownloadCommandError(RepoExitError):
+    """Error raised when download command fails."""
+
+
 class Download(Command):
     COMMON = True
     helpSummary = "Download and checkout a change"
@@ -137,15 +141,16 @@ If no project is specified try to use current directory as a project.
                 )
 
     def Execute(self, opt, args):
+        try:
+            self._ExecuteHelper(opt, args)
+        except Exception as e:
+            if isinstance(e, RepoExitError):
+                raise e
+            raise DownloadCommandError(aggregate_errors=[e])
+
+    def _ExecuteHelper(self, opt, args):
         for project, change_id, ps_id in self._ParseChangeIds(opt, args):
             dl = project.DownloadPatchSet(change_id, ps_id)
-            if not dl:
-                print(
-                    "[%s] change %d/%d not found"
-                    % (project.name, change_id, ps_id),
-                    file=sys.stderr,
-                )
-                sys.exit(1)
 
             if not opt.revert and not dl.commits:
                 print(
@@ -201,4 +206,4 @@ If no project is specified try to use current directory as a project.
                     % (project.name, mode, dl.commit),
                     file=sys.stderr,
                 )
-                sys.exit(1)
+                raise
diff --git a/subcmds/grep.py b/subcmds/grep.py
index 5cd33763..9ebd776c 100644
--- a/subcmds/grep.py
+++ b/subcmds/grep.py
@@ -17,8 +17,10 @@ import sys
 
 from color import Coloring
 from command import DEFAULT_LOCAL_JOBS, PagedCommand
-from error import GitError
+from error import GitError, InvalidArgumentsError, SilentRepoExitError
 from git_command import GitCommand
+from typing import NamedTuple
+from project import Project
 
 
 class GrepColoring(Coloring):
@@ -28,6 +30,22 @@ class GrepColoring(Coloring):
         self.fail = self.printer("fail", fg="red")
 
 
+class ExecuteOneResult(NamedTuple):
+    """Result from an execute instance."""
+
+    project: Project
+    rc: int
+    stdout: str
+    stderr: str
+    error: GitError
+
+
+class GrepCommandError(SilentRepoExitError):
+    """Grep command failure. Since Grep command
+    output already outputs errors ensure that
+    aggregate errors exit silently."""
+
+
 class Grep(PagedCommand):
     COMMON = True
     helpSummary = "Print lines matching a pattern"
@@ -246,11 +264,18 @@ contain a line that matches both expressions:
                 bare=False,
                 capture_stdout=True,
                 capture_stderr=True,
+                verify_command=True,
             )
         except GitError as e:
-            return (project, -1, None, str(e))
+            return ExecuteOneResult(project, -1, None, str(e), e)
 
-        return (project, p.Wait(), p.stdout, p.stderr)
+        try:
+            error = None
+            rc = p.Wait()
+        except GitError as e:
+            rc = 1
+            error = e
+        return ExecuteOneResult(project, rc, p.stdout, p.stderr, error)
 
     @staticmethod
     def _ProcessResults(full_name, have_rev, opt, _pool, out, results):
@@ -258,31 +283,40 @@ contain a line that matches both expressions:
         bad_rev = False
         have_match = False
         _RelPath = lambda p: p.RelPath(local=opt.this_manifest_only)
+        errors = []
 
-        for project, rc, stdout, stderr in results:
-            if rc < 0:
+        for result in results:
+            if result.rc < 0:
                 git_failed = True
-                out.project("--- project %s ---" % _RelPath(project))
+                out.project("--- project %s ---" % _RelPath(result.project))
                 out.nl()
-                out.fail("%s", stderr)
+                out.fail("%s", result.stderr)
                 out.nl()
+                errors.append(result.error)
                 continue
 
-            if rc:
+            if result.rc:
                 # no results
-                if stderr:
-                    if have_rev and "fatal: ambiguous argument" in stderr:
+                if result.stderr:
+                    if (
+                        have_rev
+                        and "fatal: ambiguous argument" in result.stderr
+                    ):
                         bad_rev = True
                     else:
-                        out.project("--- project %s ---" % _RelPath(project))
+                        out.project(
+                            "--- project %s ---" % _RelPath(result.project)
+                        )
                         out.nl()
-                        out.fail("%s", stderr.strip())
+                        out.fail("%s", result.stderr.strip())
                         out.nl()
+                    if result.error is not None:
+                        errors.append(result.error)
                 continue
             have_match = True
 
             # We cut the last element, to avoid a blank line.
-            r = stdout.split("\n")
+            r = result.stdout.split("\n")
             r = r[0:-1]
 
             if have_rev and full_name:
@@ -290,13 +324,13 @@ contain a line that matches both expressions:
                     rev, line = line.split(":", 1)
                     out.write("%s", rev)
                     out.write(":")
-                    out.project(_RelPath(project))
+                    out.project(_RelPath(result.project))
                     out.write("/")
                     out.write("%s", line)
                     out.nl()
             elif full_name:
                 for line in r:
-                    out.project(_RelPath(project))
+                    out.project(_RelPath(result.project))
                     out.write("/")
                     out.write("%s", line)
                     out.nl()
@@ -304,7 +338,7 @@ contain a line that matches both expressions:
                 for line in r:
                     print(line)
 
-        return (git_failed, bad_rev, have_match)
+        return (git_failed, bad_rev, have_match, errors)
 
     def Execute(self, opt, args):
         out = GrepColoring(self.manifest.manifestProject.config)
@@ -333,16 +367,14 @@ contain a line that matches both expressions:
         have_rev = False
         if opt.revision:
             if "--cached" in cmd_argv:
-                print(
-                    "fatal: cannot combine --cached and --revision",
-                    file=sys.stderr,
-                )
-                sys.exit(1)
+                msg = "fatal: cannot combine --cached and --revision"
+                print(msg, file=sys.stderr)
+                raise InvalidArgumentsError(msg)
             have_rev = True
             cmd_argv.extend(opt.revision)
         cmd_argv.append("--")
 
-        git_failed, bad_rev, have_match = self.ExecuteInParallel(
+        git_failed, bad_rev, have_match, errors = self.ExecuteInParallel(
             opt.jobs,
             functools.partial(self._ExecuteOne, cmd_argv),
             projects,
@@ -354,12 +386,12 @@ contain a line that matches both expressions:
         )
 
         if git_failed:
-            sys.exit(1)
+            raise GrepCommandError(
+                "error: git failures", aggregate_errors=errors
+            )
         elif have_match:
             sys.exit(0)
         elif have_rev and bad_rev:
             for r in opt.revision:
                 print("error: can't search revision %s" % r, file=sys.stderr)
-            sys.exit(1)
-        else:
-            sys.exit(1)
+        raise GrepCommandError(aggregate_errors=errors)
diff --git a/subcmds/help.py b/subcmds/help.py
index 50a48047..593bf676 100644
--- a/subcmds/help.py
+++ b/subcmds/help.py
@@ -26,6 +26,11 @@ from command import (
 )
 import gitc_utils
 from wrapper import Wrapper
+from error import RepoExitError
+
+
+class InvalidHelpCommand(RepoExitError):
+    """Invalid command passed into help."""
 
 
 class Help(PagedCommand, MirrorSafeCommand):
@@ -202,7 +207,7 @@ Displays detailed usage information about a command.
                 print(
                     "repo: '%s' is not a repo command." % name, file=sys.stderr
                 )
-                sys.exit(1)
+                raise InvalidHelpCommand(name)
 
             self._PrintCommandHelp(cmd)
 
diff --git a/subcmds/selfupdate.py b/subcmds/selfupdate.py
index d5d0a838..00376b66 100644
--- a/subcmds/selfupdate.py
+++ b/subcmds/selfupdate.py
@@ -18,6 +18,11 @@ import sys
 from command import Command, MirrorSafeCommand
 from subcmds.sync import _PostRepoUpgrade
 from subcmds.sync import _PostRepoFetch
+from error import RepoExitError
+
+
+class SelfupdateError(RepoExitError):
+    """Exit error for failed selfupdate command."""
 
 
 class Selfupdate(Command, MirrorSafeCommand):
@@ -58,9 +63,10 @@ need to be performed by an end-user.
             _PostRepoUpgrade(self.manifest)
 
         else:
-            if not rp.Sync_NetworkHalf().success:
+            result = rp.Sync_NetworkHalf()
+            if result.error:
                 print("error: can't update repo", file=sys.stderr)
-                sys.exit(1)
+                raise SelfupdateError(aggregate_errors=[result.error])
 
             rp.bare_git.gc("--auto")
             _PostRepoFetch(rp, repo_verify=opt.repo_verify, verbose=True)
diff --git a/subcmds/start.py b/subcmds/start.py
index f6355126..67ac7df9 100644
--- a/subcmds/start.py
+++ b/subcmds/start.py
@@ -21,7 +21,18 @@ from git_config import IsImmutable
 from git_command import git
 import gitc_utils
 from progress import Progress
-from project import SyncBuffer
+from project import SyncBuffer, Project
+from typing import NamedTuple
+from error import RepoExitError
+
+
+class ExecuteOneResult(NamedTuple):
+    project: Project
+    error: Exception
+
+
+class StartError(RepoExitError):
+    """Exit error for failed start command."""
 
 
 class Start(Command):
@@ -73,6 +84,7 @@ revision specified in the manifest.
         # a change, then we can't push back to it. Substitute with
         # dest_branch, if defined; or with manifest default revision instead.
         branch_merge = ""
+        error = None
         if IsImmutable(project.revisionExpr):
             if project.dest_branch:
                 branch_merge = project.dest_branch
@@ -80,7 +92,7 @@ revision specified in the manifest.
                 branch_merge = self.manifest.default.revisionExpr
 
         try:
-            ret = project.StartBranch(
+            project.StartBranch(
                 nb, branch_merge=branch_merge, revision=revision
             )
         except Exception as e:
@@ -88,11 +100,12 @@ revision specified in the manifest.
                 "error: unable to checkout %s: %s" % (project.name, e),
                 file=sys.stderr,
             )
-            ret = False
-        return (ret, project)
+            error = e
+        return ExecuteOneResult(project, error)
 
     def Execute(self, opt, args):
         nb = args[0]
+        err_projects = []
         err = []
         projects = []
         if not opt.all:
@@ -146,9 +159,10 @@ revision specified in the manifest.
             pm.end()
 
         def _ProcessResults(_pool, pm, results):
-            for result, project in results:
-                if not result:
-                    err.append(project)
+            for result in results:
+                if result.error:
+                    err_projects.append(result.project)
+                    err.append(result.error)
                 pm.update(msg="")
 
         self.ExecuteInParallel(
@@ -161,13 +175,15 @@ revision specified in the manifest.
             ),
         )
 
-        if err:
-            for p in err:
+        if err_projects:
+            for p in err_projects:
                 print(
                     "error: %s/: cannot start %s"
                     % (p.RelPath(local=opt.this_manifest_only), nb),
                     file=sys.stderr,
                 )
             msg_fmt = "cannot start %d project(s)"
-            self.git_event_log.ErrorEvent(msg_fmt % (len(err)), msg_fmt)
-            sys.exit(1)
+            self.git_event_log.ErrorEvent(
+                msg_fmt % (len(err_projects)), msg_fmt
+            )
+            raise StartError(aggregate_errors=err)