json progress: emit info (current $something)

docs/internals/frontends.rst

@@ -22,7 +22,8 @@ where each line is a JSON object. The *type* key of the object determines its ot
 
 Since JSON can only encode text, any string representing a file system path may miss non-text parts.
 
-The following types are in use:
+The following types are in use. Progress information is governed by the usual rules for progress information,
+it is not produced unless ``--progress`` is specified.
 
 archive_progress
     Output during operations creating archives (:ref:`borg_create` and :ref:`borg_recreate`).
@@ -67,6 +68,8 @@ progress_percent
         A formatted progress message, this will include the percentage and perhaps other information
     current
         Current value (always less-or-equal to *total*)
+    info
+        Array that describes the current item, may be *none*, contents depend on *msgid*
     total
         Total value
 
@@ -218,10 +221,14 @@ Operations
     - cache.begin_transaction
     - cache.commit
     - cache.sync
+
+      *info* is one string element, the name of the archive currently synced.
     - repository.compact_segments
     - repository.replay_segments
     - repository.check_segments
     - check.verify_data
     - extract
+
+      *info* is one string element, the name of the path currently extracted.
     - extract.permissions
     - archive.delete

src/borg/helpers.py

@@ -1508,13 +1508,13 @@ class ProgressIndicatorPercent(ProgressIndicatorBase):
                     if terminal_space != -1:
                         space = terminal_space - len(self.msg % tuple([pct] + info[:-1] + ['']))
                         info[-1] = ellipsis_truncate(info[-1], space)
-                return self.output(self.msg % tuple([pct] + info), justify=False)
+                return self.output(self.msg % tuple([pct] + info), justify=False, info=info)
 
             return self.output(self.msg % pct)
 
-    def output(self, message, justify=True):
+    def output(self, message, justify=True, info=None):
         if self.json:
-            self.output_json(message=message, current=self.counter, total=self.total)
+            self.output_json(message=message, current=self.counter, total=self.total, info=info)
         else:
             if justify:
                 message = justify_to_terminal_size(message)