Limit the history to 20 entries per window

Reduces the amount of work and API calls we need to do before showing
the panel while at the same time reducing the amount of data we store
in the workspace.

Going back more than 20 tabs in the stack is very unlikely and the only
remaining downside is that we will have no history at all after the
user closed these 20 tabs, but in that case it is questionable to
assume that the user would return exactly to the work they did before
closing these 20 tabs anyway.

A configuration option is not added because this seems like a reasonable
default. If configuration is wanted, the user can override our new
`constants.py` file instead.

Closes #4

Author: FichteFoll

plugin/constants.py

@@ -0,0 +1 @@
+TAB_HISTORY_LIMIT = 20

plugin/history.py

@@ -3,6 +3,7 @@
 from typing import Any, cast
 
 from ._compat import sublime
+from .constants import TAB_HISTORY_LIMIT
 from .sheets import SheetIdentity, find_sheet_by_identity_and_group, sheet_identity
 from .state import (
     GroupSelectionState,
@@ -238,6 +239,8 @@ def prune_history_stack(
     updated_stack: list[GroupSelectionState] = []
     seen_identities: list[SheetIdentity] = list(removed_identities or [])
     for group_state in group_state_stack:
+        if len(updated_stack) >= TAB_HISTORY_LIMIT:
+            break
         pruned_group_state = prune_group_state(
             group_state,
             seen_identities,

plugin/mru.py

@@ -3,6 +3,7 @@
 from dataclasses import dataclass
 
 from .captions import caption_for_sheet_identities
+from .constants import TAB_HISTORY_LIMIT
 from .sheets import SheetIdentity, sheet_identity
 from .state import GroupSelectionState, SheetSelectionHistory
 
@@ -30,6 +31,8 @@ def collect_entries(window, history: SheetSelectionHistory) -> list[Entry]:
             seen_identities.update(_selection_identity_keys(group_state))
 
     for sheet in _non_transient_sheets_in_group(window, active_group):
+        if len(entries) >= TAB_HISTORY_LIMIT:
+            break
         identity = _identity_key(sheet_identity(sheet, window))
         if identity in seen_identities:
             continue