check: handle Ctrl-C at safe boundaries (#7893)

src/borg/archive.py

@@ -32,7 +32,7 @@
 from .helpers import BackupOSError, BackupPermissionError, BackupFileNotFoundError, BackupIOError
 from .helpers import HardLinkManager
 from .helpers import ChunkIteratorFileWrapper, open_item
-from .helpers import Error, IntegrityError, set_ec
+from .helpers import Error, IntegrityError, set_ec, sig_int
 from .platform import uid2user, user2uid, gid2group, group2gid, get_birthtime_ns
 from .helpers import parse_timestamp, archive_ts_now, CompressionSpec
 from .helpers import OutputTimestamp, format_timedelta, format_file_size, file_status, FileSize
@@ -1879,12 +1879,25 @@ def check(
                 rebuild_manifest = True
         if rebuild_manifest:
             self.manifest = self.rebuild_manifest()
-        if find_lost_archives:
+        # Skip the remaining scans on Ctrl-C, but still run finish() below.
+        if find_lost_archives and not sig_int:
             self.rebuild_archives_directory()
-        self.rebuild_archives(
-            match=match, first=first, last=last, sort_by=sort_by, older=older, oldest=oldest, newer=newer, newest=newest
-        )
+        if not sig_int:
+            self.rebuild_archives(
+                match=match,
+                first=first,
+                last=last,
+                sort_by=sort_by,
+                older=older,
+                oldest=oldest,
+                newer=newer,
+                newest=newest,
+            )
+        # finish() drops the chunk index and writes the manifest; run it even on Ctrl-C so --repair
+        # leaves a valid index (#9850).
         self.finish()
+        if sig_int:
+            raise Error("Got Ctrl-C / SIGINT.")
         if self.error_found:
             logger.error("Archive consistency check complete, problems found.")
         else:
@@ -1937,6 +1950,8 @@ def verify_data(self):
             total=chunks_count, msg="Verifying data %6.2f%%", step=0.01, msgid="check.verify_data"
         )
         for chunk_id, _ in self.chunks.iteritems():
+            if sig_int:  # stop at a chunk boundary
+                break
             pi.show()
             try:
                 encrypted_data = self.repository.get(chunk_id)
@@ -2023,6 +2038,8 @@ def valid_archive(obj):
             msgid="check.rebuild_archives_directory",
         )
         for chunk_id, _ in self.chunks.iteritems():
+            if sig_int:  # stop at a chunk boundary
+                break
             pi.show()
             cdata = self.repository.get(chunk_id, read_data=False)  # only get metadata
             try:
@@ -2216,6 +2233,9 @@ def valid_item(obj):
             total=num_archives, msg="Checking archives %3.1f%%", step=0.1, msgid="check.rebuild_archives"
         )
         for i, info in enumerate(archive_infos):
+            if sig_int:
+                # Break only between archives: --repair rewrites each archive as a whole below.
+                break
             pi.show(i)
             archive_id, archive_id_hex = info.id, bin_to_hex(info.id)
             try:

src/borg/archiver/check_cmd.py

@@ -3,8 +3,8 @@
 from ._common import with_repository, Highlander
 from ..archive import ArchiveChecker
 from ..constants import *  # NOQA
-from ..helpers import set_ec, EXIT_WARNING, CancelledByUser, CommandError, IntegrityError
-from ..helpers import yes, ArchiveFormatter, use_iec_units
+from ..helpers import set_ec, EXIT_WARNING, CancelledByUser, CommandError, Error, IntegrityError
+from ..helpers import yes, ArchiveFormatter, use_iec_units, sig_int
 from ..helpers.argparsing import ArgumentParser
 
 from ..logger import create_logger
@@ -66,6 +66,8 @@ def do_check(self, args, repository):
         if not args.archives_only:
             if not repository.check(repair=args.repair, max_duration=args.max_duration):
                 set_ec(EXIT_WARNING)
+            if sig_int:  # repository check interrupted; skip the archive check
+                raise Error("Got Ctrl-C / SIGINT.")
         if not args.repo_only and not archive_checker.check(
             repository,
             verify_data=args.verify_data,

src/borg/repository.py

@@ -813,6 +813,10 @@ def store_list(namespace):
             pack_infos = store_list("packs")
             pack_pi = ProgressIndicatorPercent(total=len(pack_infos), msg="Checking packs %3.0f%%", msgid="check.packs")
             for info in pack_infos:
+                if sig_int:  # save progress so a later check resumes, then stop
+                    logger.info(f"Interrupted repository check, {len(tracker)} packs checked so far.")
+                    tracker.save()
+                    break
                 self._lock_refresh()
                 pack_pi.show(increase=1)  # advance for skipped packs too, so the bar tracks packs/, not work done
                 pack_id = hex_to_bin(info.name)

src/borg/testsuite/archiver/check_cmd_test.py

@@ -65,6 +65,60 @@ def test_check_usage(archivers, request):
     assert "archive2" in output
 
 
+def test_check_soft_interrupt(archivers, request):
+    """A Ctrl-C during a read-only check stops at a safe boundary and raises 'Got Ctrl-C' (#7893).
+    It changes nothing, so a normal check still passes afterwards."""
+    from ...archive import ArchiveChecker
+    from ...helpers import sig_int, Error
+
+    archiver = request.getfixturevalue(archivers)
+    check_cmd_setup(archiver)
+
+    try:
+        with Repository(archiver.repository_path, exclusive=True) as repository:
+            # repository check: stops at a pack boundary, still reports no errors.
+            sig_int._sig_int_triggered = True
+            assert repository.check() is True
+        with Repository(archiver.repository_path, exclusive=True) as repository:
+            # archive check: runs finish(), then raises.
+            sig_int._sig_int_triggered = True
+            with pytest.raises(Error, match="Got Ctrl-C"):
+                ArchiveChecker().check(repository, verify_data=True, sort_by="ts", format="{archive} {time} {id}")
+    finally:
+        sig_int._sig_int_triggered = False  # reset the global flag for the following tests
+
+    cmd(archiver, "check", exit_code=0)
+
+
+def test_check_repair_soft_interrupt(archivers, request, monkeypatch):
+    """A Ctrl-C after the first archive of a --repair archive check stops at the archive boundary, runs
+    finish() (dropping the chunk index, writing the manifest), then raises. A later check confirms the
+    repository is still consistent."""
+    from ...archive import ArchiveChecker
+    from ...manifest import Archives
+    from ...helpers import sig_int, Error
+
+    archiver = request.getfixturevalue(archivers)
+    check_cmd_setup(archiver)  # two archives
+
+    orig_create = Archives.create
+
+    def create_then_interrupt(self, *args, **kwargs):
+        orig_create(self, *args, **kwargs)
+        sig_int._sig_int_triggered = True  # one Ctrl-C after the first archive was rebuilt
+
+    monkeypatch.setattr(Archives, "create", create_then_interrupt)
+    try:
+        with Repository(archiver.repository_path, exclusive=True) as repository:
+            with pytest.raises(Error, match="Got Ctrl-C"):
+                ArchiveChecker().check(repository, repair=True, sort_by="ts", format="{archive} {time} {id}")
+    finally:
+        sig_int._sig_int_triggered = False  # reset the global flag for the following tests
+
+    # a normal check does not rebuild archives, so the patched Archives.create never fires here
+    cmd(archiver, "check", exit_code=0)
+
+
 def test_date_matching(archivers, request):
     archiver = request.getfixturevalue(archivers)
     check_cmd_setup(archiver)