fix(git): small bug fixes

lua/git/cmd.lua

@@ -93,11 +93,17 @@ local function run_in_split(worktree, args, conf)
     vim.b[buf].git_worktree = worktree
     if conf.needs_ref then
         local user_ref = first_positional(args, 2) or "HEAD"
-        local sha = repo.rev_parse(worktree, user_ref, true) or user_ref
-        vim.b[buf].git_ref = sha
-        vim.b[buf].git_parent_ref =
-            repo.rev_parse(worktree, user_ref .. "^", true)
-        pcall(vim.api.nvim_buf_set_name, buf, "git://" .. sha .. "/")
+        local sha = repo.rev_parse(worktree, user_ref, true)
+        if sha then
+            vim.b[buf].git_ref = sha
+            vim.b[buf].git_parent_ref =
+                repo.rev_parse(worktree, user_ref .. "^", true)
+        end
+        pcall(
+            vim.api.nvim_buf_set_name,
+            buf,
+            "git://" .. (sha or user_ref) .. "/"
+        )
     end
     vim.bo[buf].filetype = conf.ft
 

lua/git/status_win.lua

@@ -311,6 +311,10 @@ local function render(bufnr, branch, groups)
         })
     end
     state[bufnr].lines = meta
+    -- The diff windows we last opened may now be showing content for an
+    -- entry whose underlying file has changed. Drop the cache so the next
+    -- show_diff recomputes pre/post panes instead of short-circuiting.
+    state[bufnr].last_shown_key = nil
 end
 
 ---@param bufnr integer