feat(git): per-key cache invalidation and optional submodule tracking

lua/git/core/status.lua

@@ -274,6 +274,49 @@ local function strip_dir_slash(path)
     return path
 end
 
+---@param a ow.Git.Status.Entry?
+---@param b ow.Git.Status.Entry?
+---@return boolean
+function M.entry_equal(a, b)
+    if a == nil or b == nil then
+        return a == b
+    end
+    if a.kind ~= b.kind or a.path ~= b.path then
+        return false
+    end
+    if a.kind == "changed" then
+        ---@cast a ow.Git.Status.ChangedEntry
+        ---@cast b ow.Git.Status.ChangedEntry
+        return a.staged == b.staged
+            and a.unstaged == b.unstaged
+            and a.orig == b.orig
+    end
+    if a.kind == "unmerged" then
+        ---@cast a ow.Git.Status.UnmergedEntry
+        ---@cast b ow.Git.Status.UnmergedEntry
+        return a.conflict == b.conflict
+    end
+    return true
+end
+
+---@param prior table<string, ow.Git.Status.Entry>
+---@param next_ table<string, ow.Git.Status.Entry>
+---@return table<string, true>
+function M.diff_entries(prior, next_)
+    local paths = {}
+    for path, entry in pairs(next_) do
+        if not M.entry_equal(prior[path], entry) then
+            paths[path] = true
+        end
+    end
+    for path in pairs(prior) do
+        if next_[path] == nil then
+            paths[path] = true
+        end
+    end
+    return paths
+end
+
 ---@param stdout string
 ---@return ow.Git.Status
 function M.parse(stdout)