feat(object): use <commit>:<path> URIs when entering a file from a commit dump

lua/git/object.lua

@@ -337,10 +337,45 @@ local function side_buf(r, blob, path)
 end
 
 ---@param r ow.Git.Repo
+---@param commit string
+---@param parent boolean
+---@param path string
+---@return integer?
+local function commit_side_buf(r, commit, parent, path)
+    local rev = parent and (commit .. "^") or commit
+    local sha = r:rev_parse(rev, false)
+    if not sha then
+        return nil
+    end
+    if not r:rev_parse(sha .. ":" .. path, false) then
+        return nil
+    end
+    return M.buf_for(r, Revision.new({ base = sha, path = path }))
+end
+
+---@param r ow.Git.Repo
+---@param commit string?
+---@param parent boolean
 ---@param blob string?
 ---@param path string
-local function load_side(r, blob, path)
-    local buf = side_buf(r, blob, path)
+---@return integer?
+local function side(r, commit, parent, blob, path)
+    if commit then
+        local buf = commit_side_buf(r, commit, parent, path)
+        if buf then
+            return buf
+        end
+    end
+    return side_buf(r, blob, path)
+end
+
+---@param r ow.Git.Repo
+---@param commit string?
+---@param parent boolean
+---@param blob string?
+---@param path string
+local function load_side(r, commit, parent, blob, path)
+    local buf = side(r, commit, parent, blob, path)
     if not buf then
         util.error("no content for %s", path)
         return
@@ -350,14 +385,15 @@ local function load_side(r, blob, path)
 end
 
 ---@param r ow.Git.Repo
+---@param commit string?
 ---@param section ow.Git.DiffSection
-local function open_section(r, section)
+local function open_section(r, commit, section)
     if not section.blob_a or not section.blob_b then
         util.error("no index line, cannot determine blob SHAs")
         return
     end
-    local left = side_buf(r, section.blob_a, section.path_a)
-    local right = side_buf(r, section.blob_b, section.path_b)
+    local left = side(r, commit, true, section.blob_a, section.path_a)
+    local right = side(r, commit, false, section.blob_b, section.path_b)
     if left and right then
         vim.cmd.normal({ "m'", bang = true })
         vim.api.nvim_set_current_buf(right)
@@ -377,6 +413,21 @@ local function open_section(r, section)
     vim.api.nvim_set_current_buf(buf)
 end
 
+---@param r ow.Git.Repo
+---@param buf integer
+---@return string?
+local function commit_in_buf(r, buf)
+    local name = vim.api.nvim_buf_get_name(buf)
+    if not vim.startswith(name, M.URI_PREFIX) then
+        return nil
+    end
+    local rev = M.parse_uri(name)
+    if not rev or not rev.base or rev.path then
+        return nil
+    end
+    return r:rev_parse(rev.base .. "^{commit}", false)
+end
+
 ---@class ow.Git.Object.OpenOpts
 ---@field split (false|"above"|"below"|"left"|"right")?
 
@@ -423,7 +474,7 @@ function M.open_under_cursor()
         line:match("^%d+ (%w+) (%x+)\t(.+)$")
     if entry_sha then
         if entry_type == "blob" then
-            load_side(r, entry_sha, entry_name --[[@as string]])
+            load_side(r, nil, false, entry_sha, entry_name --[[@as string]])
         else
             M.open(r, entry_sha, { split = false })
         end
@@ -435,24 +486,26 @@ function M.open_under_cursor()
         return false
     end
 
+    local commit = commit_in_buf(r, vim.api.nvim_get_current_buf())
+
     if line:match("^diff %-%-git ") then
-        open_section(r, section)
+        open_section(r, commit, section)
         return true
     end
     if line:match("^%-%-%- ") then
-        load_side(r, section.blob_a, section.path_a)
+        load_side(r, commit, true, section.blob_a, section.path_a)
         return true
     end
     if line:match("^%+%+%+ ") then
-        load_side(r, section.blob_b, section.path_b)
+        load_side(r, commit, false, section.blob_b, section.path_b)
         return true
     end
     local prefix = line:sub(1, 1)
     if prefix == "+" then
-        load_side(r, section.blob_b, section.path_b)
+        load_side(r, commit, false, section.blob_b, section.path_b)
         return true
     elseif prefix == "-" then
-        load_side(r, section.blob_a, section.path_a)
+        load_side(r, commit, true, section.blob_a, section.path_a)
         return true
     end
     return false