feat(blame): show commit's hunk in the line popup

2026-05-26 23:25:08 +02:00
parent 428ded2c4c
commit ff7b20ec46
7 changed files with 589 additions and 65 deletions
@@ -1,10 +1,12 @@
 local object = require("git.object")
+local popup = require("git.core.popup")
 local repo = require("git.core.repo")
 local util = require("git.core.util")

 local M = {}

 local NS_POPUP = vim.api.nvim_create_namespace("ow.git.blame.popup")
+local NS_OVERFLOW = vim.api.nvim_create_namespace("ow.git.blame.popup.overflow")

 local ZERO_SHA = string.rep("0", 40)

@@ -19,6 +21,8 @@ local ZERO_SHA = string.rep("0", 40)
 ---@class ow.Git.Blame.Result
 ---@field commits table<string, ow.Git.Blame.Commit>
 ---@field line_sha table<integer, string>
+---@field line_orig table<integer, integer>
+---@field line_file table<integer, string>

 ---@class ow.Git.Blame.Source
 ---@field repo ow.Git.Repo
@@ -31,6 +35,8 @@ local ZERO_SHA = string.rep("0", 40)
 ---@field revision string?
 ---@field commits table<string, ow.Git.Blame.Commit>
 ---@field line_sha table<integer, string>
+---@field line_orig table<integer, integer>
+---@field line_file table<integer, string>
 ---@field tick integer?
 ---@field epoch integer
 ---@field pending fun()[]
@@ -72,20 +78,33 @@ local function parse_porcelain(stdout)
    local commits = {}
    ---@type table<integer, string>
    local line_sha = {}
+    ---@type table<integer, integer>
+    local line_orig = {}
+    ---@type table<integer, string>
+    local line_file = {}
    local cur_sha ---@type string?
    local cur_lnum ---@type integer?
+    local cur_orig ---@type integer?
+    local cur_file ---@type string?
    for _, line in ipairs(util.split_lines(stdout)) do
        if line:sub(1, 1) == "\t" then
-            if cur_sha and cur_lnum then
+            if cur_sha and cur_lnum and cur_orig then
                line_sha[cur_lnum] = cur_sha
+                line_orig[cur_lnum] = cur_orig
+                if cur_file then
+                    line_file[cur_lnum] = cur_file
+                end
            end
            cur_sha = nil
            cur_lnum = nil
+            cur_orig = nil
+            cur_file = nil
        else
-            local sha, final = line:match("^(%x+) %d+ (%d+)")
+            local sha, orig, final = line:match("^(%x+) (%d+) (%d+)")
            if sha and #sha >= 40 then
                cur_sha = sha
-                cur_lnum = tonumber(final) --[[@as integer?]]
+                cur_orig = tonumber(orig) --[[@as integer]]
+                cur_lnum = tonumber(final) --[[@as integer]]
                if not commits[sha] then
                    commits[sha] = {
                        sha = sha,
@@ -99,7 +118,9 @@ local function parse_porcelain(stdout)
            else
                local key, value = line:match("^(%S+) (.*)$")
                local commit = cur_sha and commits[cur_sha]
-                if commit and key then
+                if key == "filename" and value then
+                    cur_file = value
+                elseif commit and key then
                    if key == "author" then
                        commit.author = value
                    elseif key == "author-mail" then
@@ -115,7 +136,12 @@ local function parse_porcelain(stdout)
            end
        end
    end
-    return { commits = commits, line_sha = line_sha }
+    return {
+        commits = commits,
+        line_sha = line_sha,
+        line_orig = line_orig,
+        line_file = line_file,
+    }
 end

 ---@param line_count integer
@@ -138,6 +164,8 @@ local function synth_uncommitted(line_count)
            },
        },
        line_sha = line_sha,
+        line_orig = {},
+        line_file = {},
    }
 end

@@ -219,6 +247,8 @@ local function ensure_state(buf)
        revision = src.revision,
        commits = {},
        line_sha = {},
+        line_orig = {},
+        line_file = {},
        tick = nil,
        epoch = 0,
        pending = {},
@@ -266,6 +296,8 @@ local function run_blame(state, buf, done)
            or synth_uncommitted(vim.api.nvim_buf_line_count(buf))
        state.commits = data.commits
        state.line_sha = data.line_sha
+        state.line_orig = data.line_orig
+        state.line_file = data.line_file
        state.tick = tick
        local pending = state.pending
        state.pending = {}
@@ -275,20 +307,101 @@ local function run_blame(state, buf, done)
    end)
 end

---@param lines string[]
---@return integer width
---@return integer height
-local function size_for(lines)
-    local width = 1
-    for _, l in ipairs(lines) do
-        local w = vim.api.nvim_strwidth(l)
-        if w > width then
-            width = w
+local NEW_FILE_MARKER = "(new file)"
+
+---@param diff_text string
+---@param orig_line integer
+---@return string[]?
+local function extract_commit_hunk(diff_text, orig_line)
+    local lines = util.split_lines(diff_text)
+    for _, line in ipairs(lines) do
+        if line == "--- /dev/null" then
+            return { NEW_FILE_MARKER }
        end
    end
-    width = math.min(math.max(width + 1, 30), vim.o.columns - 4)
-    local height = math.min(math.max(#lines, 1), math.floor(vim.o.lines / 2))
-    return width, height
+    local hunk_starts = {} ---@type integer[]
+    local target ---@type integer?
+    for i, line in ipairs(lines) do
+        local c, d = line:match("^@@ %-%d+,?%d* %+(%d+),?(%d*) @@")
+        if c then
+            table.insert(hunk_starts, i)
+            if not target then
+                local ns = tonumber(c) --[[@as integer]]
+                local nc = (d == "" or d == nil) and 1 or tonumber(d) --[[@as integer]]
+                if orig_line >= ns and orig_line < ns + nc then
+                    target = #hunk_starts
+                end
+            end
+        end
+    end
+    if not target then
+        return nil
+    end
+    local out = {} ---@type string[]
+    table.insert(out, ("Hunk %d of %d"):format(target, #hunk_starts))
+    table.insert(out, "")
+    local start_idx = hunk_starts[target]
+    local end_idx = hunk_starts[target + 1] and (hunk_starts[target + 1] - 1)
+        or #lines
+    for j = start_idx, end_idx do
+        local line = lines[j] --[[@as string]]
+        if line:match("^diff %-%-git") then
+            break
+        end
+        table.insert(out, line)
+    end
+    return out
+end
+
+local POPUP_SEP = "GIT_BLAME_POPUP_SEP"
+
+---@param r ow.Git.Repo
+---@param sha string
+---@param rel string
+---@param orig_line integer
+---@param done fun(message: string[]?, hunk: string[]?)
+local function fetch_show(r, sha, rel, orig_line, done)
+    util.git({
+        "show",
+        "--diff-merges=first-parent",
+        "--format=%B%n" .. POPUP_SEP .. "%n",
+        sha,
+        "--",
+        rel,
+    }, {
+        cwd = r.worktree,
+        silent = true,
+        on_exit = function(res)
+            if res.code ~= 0 then
+                done(nil, nil)
+                return
+            end
+            local lines = util.split_lines(res.stdout or "")
+            local sep_idx ---@type integer?
+            for i, line in ipairs(lines) do
+                if line == POPUP_SEP then
+                    sep_idx = i
+                    break
+                end
+            end
+            if not sep_idx then
+                done(nil, nil)
+                return
+            end
+            local message = {} ---@type string[]
+            for i = 1, sep_idx - 1 do
+                table.insert(message, lines[i])
+            end
+            while #message > 0 and message[#message] == "" do
+                table.remove(message)
+            end
+            local diff_text = table.concat(lines, "\n", sep_idx + 1) ---@type string
+            done(
+                #message > 0 and message or nil,
+                extract_commit_hunk(diff_text, orig_line)
+            )
+        end,
+    })
 end

 local popup_win ---@type integer?
@@ -303,14 +416,23 @@ end
 ---@param pbuf integer
 ---@param win integer
 ---@param head string[]
---@param body string[]?
+---@param message string[]?
+---@param diff string[]?
 ---@param sha_len integer?
 ---@param date_col integer?
-local function apply_popup(pbuf, win, head, body, sha_len, date_col)
-    local lines = {}
+local function apply_popup(pbuf, win, head, message, diff, sha_len, date_col)
+    local lines = {} ---@type string[]
    vim.list_extend(lines, head)
-    if body then
-        vim.list_extend(lines, body)
+    if message then
+        vim.list_extend(lines, message)
+    end
+    local diff_start ---@type integer?
+    if diff then
+        if #lines > #head then
+            table.insert(lines, "")
+        end
+        diff_start = #lines
+        vim.list_extend(lines, diff)
    end
    vim.bo[pbuf].modifiable = true
    vim.api.nvim_buf_set_lines(pbuf, 0, -1, false, lines)
@@ -334,9 +456,32 @@ local function apply_popup(pbuf, win, head, body, sha_len, date_col)
            hl_group = "GitBlameDate",
        })
    end
-    local width, height = size_for(lines)
+    if diff_start and diff then
+        if #diff == 1 and diff[1] == NEW_FILE_MARKER then
+            pcall(
+                vim.api.nvim_buf_set_extmark,
+                pbuf,
+                NS_POPUP,
+                diff_start,
+                0,
+                { line_hl_group = "GitHunkAdded" }
+            )
+        else
+            util.paint_diff_lines(pbuf, NS_POPUP, diff, diff_start)
+            pcall(
+                vim.api.nvim_buf_set_extmark,
+                pbuf,
+                NS_POPUP,
+                diff_start,
+                0,
+                { line_hl_group = "GitHunkAnnotation" }
+            )
+        end
+    end
+    local width, height = popup.size_for(lines)
    pcall(vim.api.nvim_win_set_width, win, width)
    pcall(vim.api.nvim_win_set_height, win, height)
+    popup.paint_overflow(pbuf, win, NS_OVERFLOW)
 end

 ---@param watch_buf integer
@@ -362,18 +507,23 @@ local function setup_popup_autocmds(watch_buf, pbuf, win)
            pcall(vim.api.nvim_del_augroup_by_name, "ow.git.blame.popup")
        end,
    })
+    vim.api.nvim_create_autocmd("WinScrolled", {
+        group = group,
+        pattern = tostring(win),
+        callback = function()
+            popup.paint_overflow(pbuf, win, NS_OVERFLOW)
+        end,
+    })
    vim.keymap.set("n", "q", close_popup, { buffer = pbuf, nowait = true })
 end

---@param r ow.Git.Repo
---@param commits table<string, ow.Git.Blame.Commit>
---@param line_sha table<integer, string>
+---@param state ow.Git.Blame.BufState
 ---@param lnum integer
 ---@param watch_buf integer
-local function open_popup(r, commits, line_sha, lnum, watch_buf)
+local function open_popup(state, lnum, watch_buf)
    close_popup()
-    local sha = line_sha[lnum]
-    local commit = sha and commits[sha]
+    local sha = state.line_sha[lnum]
+    local commit = sha and state.commits[sha]
    if not commit then
        util.warning("git blame: no blame information for line %d", lnum)
        return
@@ -393,15 +543,16 @@ local function open_popup(r, commits, line_sha, lnum, watch_buf)
            "",
        }
    end
-    local body = sha_len and { commit.summary } or nil
-    local lines = {}
-    vim.list_extend(lines, head)
-    if body then
-        vim.list_extend(lines, body)
-    end
-    local width, height = size_for(lines)
+    local message = sha_len and { commit.summary } or nil ---@type string[]?
+    local diff ---@type string[]?
    local pbuf = vim.api.nvim_create_buf(false, true)
    vim.bo[pbuf].bufhidden = "wipe"
+    local initial = {} ---@type string[]
+    vim.list_extend(initial, head)
+    if message then
+        vim.list_extend(initial, message)
+    end
+    local width, height = popup.size_for(initial)
    local win = vim.api.nvim_open_win(pbuf, false, {
        relative = "cursor",
        row = 1,
@@ -411,29 +562,37 @@ local function open_popup(r, commits, line_sha, lnum, watch_buf)
        style = "minimal",
    })
    popup_win = win
-    apply_popup(pbuf, win, head, body, sha_len, date_col)
+
+    local function redraw()
+        apply_popup(pbuf, win, head, message, diff, sha_len, date_col)
+    end
+
+    redraw()
    setup_popup_autocmds(watch_buf, pbuf, win)
    if not sha_len then
        return
    end
-    util.git({ "show", "-s", "--format=%B", sha }, {
-        cwd = r.worktree,
-        silent = true,
-        on_exit = function(res)
+    local orig = state.line_orig[lnum]
+    local rel = state.line_file[lnum] or state.rel
+    if not orig then
+        return
+    end
+    fetch_show(state.repo, sha, rel, orig, function(msg, hunk)
        if
            popup_win ~= win
            or not vim.api.nvim_win_is_valid(win)
            or not vim.api.nvim_buf_is_valid(pbuf)
-                or res.code ~= 0
        then
            return
        end
-            local msg = util.split_lines(res.stdout or "")
-            if #msg > 0 then
-                apply_popup(pbuf, win, head, msg, sha_len, date_col)
+        if msg then
+            message = msg
        end
-        end,
-    })
+        if hunk then
+            diff = hunk
+        end
+        redraw()
+    end)
 end

 ---@param buf integer?
@@ -457,7 +616,7 @@ function M.line_popup(buf)
        then
            return
        end
-        open_popup(state.repo, state.commits, state.line_sha, lnum, buf)
+        open_popup(state, lnum, buf)
    end)
 end

@@ -0,0 +1,82 @@
+local M = {}
+
+---@param win integer
+---@return boolean
+local function has_border(win)
+    local b = vim.api.nvim_win_get_config(win).border
+    if not b or b == "none" or b == "" then
+        return false
+    end
+    if type(b) == "table" and #b == 0 then
+        return false
+    end
+    return true
+end
+
+---@param lines string[]
+---@param opts? { min_width?: integer, padding?: integer }
+---@return integer width
+---@return integer height
+function M.size_for(lines, opts)
+    opts = opts or {}
+    local width = 1
+    for _, l in ipairs(lines) do
+        local w = vim.api.nvim_strwidth(l)
+        if w > width then
+            width = w
+        end
+    end
+    width = math.min(
+        math.max(width + (opts.padding or 1), opts.min_width or 30),
+        100,
+        vim.o.columns - 4
+    )
+    local height =
+        math.min(math.max(#lines, 1), 20, math.floor(vim.o.lines / 2))
+    return width, height
+end
+
+---@param pbuf integer
+---@param win integer
+---@param ns integer
+function M.paint_overflow(pbuf, win, ns)
+    vim.schedule(function()
+        if
+            not vim.api.nvim_buf_is_valid(pbuf)
+            or not vim.api.nvim_win_is_valid(win)
+        then
+            return
+        end
+        vim.api.nvim_buf_clear_namespace(pbuf, ns, 0, -1)
+        local total = vim.api.nvim_buf_line_count(pbuf)
+        local top, bottom = unpack(vim.api.nvim_win_call(win, function()
+            return { vim.fn.line("w0"), vim.fn.line("w$") }
+        end)) ---@cast top integer
+        ---@cast bottom integer
+        local needs_top = top > 1
+        local needs_bottom = bottom < total
+        if has_border(win) then
+            pcall(vim.api.nvim_win_set_config, win, {
+                title = needs_top and { { "▲ ", "FloatBorder" } } or "",
+                title_pos = needs_top and "right" or nil,
+                footer = needs_bottom and { { "▼ ", "FloatBorder" } } or "",
+                footer_pos = needs_bottom and "right" or nil,
+            })
+            return
+        end
+        if needs_top then
+            pcall(vim.api.nvim_buf_set_extmark, pbuf, ns, top - 1, 0, {
+                virt_text = { { "▲ ", "GitPopupEnd" } },
+                virt_text_pos = "right_align",
+            })
+        end
+        if needs_bottom then
+            pcall(vim.api.nvim_buf_set_extmark, pbuf, ns, bottom - 1, 0, {
+                virt_text = { { "▼ ", "GitPopupEnd" } },
+                virt_text_pos = "right_align",
+            })
+        end
+    end)
+end
+
+return M
@@ -120,6 +120,34 @@ function M.split_lines(content)
    return lines
 end

+---@param buf integer
+---@param ns integer
+---@param lines string[]
+---@param start_row integer  0-indexed row of the first line in `lines`
+function M.paint_diff_lines(buf, ns, lines, start_row)
+    for i, line in ipairs(lines) do
+        local hl ---@type string?
+        local prefix = line:sub(1, 1)
+        if prefix == "+" then
+            hl = "GitHunkAdded"
+        elseif prefix == "-" then
+            hl = "GitHunkRemoved"
+        elseif vim.startswith(line, "@@") then
+            hl = "GitHunkHeader"
+        end
+        if hl then
+            pcall(
+                vim.api.nvim_buf_set_extmark,
+                buf,
+                ns,
+                start_row + i - 1,
+                0,
+                { line_hl_group = hl }
+            )
+        end
+    end
+end
+
 ---@class ow.Git.Util.DebounceHandle
 ---@field cancel fun()
 ---@field flush fun()
@@ -1,3 +1,4 @@
+local popup = require("git.core.popup")
 local repo = require("git.core.repo")
 local util = require("git.core.util")

@@ -5,6 +6,9 @@ local M = {}

 local NS_SIGNS = vim.api.nvim_create_namespace("ow.git.hunks")
 local NS_OVERLAY = vim.api.nvim_create_namespace("ow.git.hunks.overlay")
+local NS_PREVIEW = vim.api.nvim_create_namespace("ow.git.hunks.preview")
+local NS_PREVIEW_OVERFLOW =
+    vim.api.nvim_create_namespace("ow.git.hunks.preview.overflow")

 ---@alias ow.Git.Hunks.HunkType "add"|"change"|"delete"

@@ -905,16 +909,9 @@ function M.preview_hunk(buf)
    local lines = hunk_body(h)
    local pbuf = vim.api.nvim_create_buf(false, true)
    vim.api.nvim_buf_set_lines(pbuf, 0, -1, false, lines)
-    vim.bo[pbuf].filetype = "diff"
    vim.bo[pbuf].bufhidden = "wipe"
-    local width = 0
-    for _, l in ipairs(lines) do
-        if #l > width then
-            width = #l
-        end
-    end
-    width = math.min(math.max(width + 2, 40), vim.o.columns - 4)
-    local height = math.min(#lines, math.floor(vim.o.lines / 2))
+    util.paint_diff_lines(pbuf, NS_PREVIEW, lines, 0)
+    local width, height = popup.size_for(lines, { min_width = 40, padding = 2 })
    local win = vim.api.nvim_open_win(pbuf, false, {
        relative = "cursor",
        row = 1,
@@ -924,6 +921,7 @@ function M.preview_hunk(buf)
        style = "minimal",
    })
    preview_win = win
+    popup.paint_overflow(pbuf, win, NS_PREVIEW_OVERFLOW)

    local function close()
        if vim.api.nvim_win_is_valid(win) then
@@ -949,6 +947,13 @@ function M.preview_hunk(buf)
            pcall(vim.api.nvim_del_augroup_by_name, "ow.git.hunks.preview")
        end,
    })
+    vim.api.nvim_create_autocmd("WinScrolled", {
+        group = group,
+        pattern = tostring(win),
+        callback = function()
+            popup.paint_overflow(pbuf, win, NS_PREVIEW_OVERFLOW)
+        end,
+    })
    vim.keymap.set("n", "q", close, { buffer = pbuf, nowait = true })
 end

@@ -40,12 +40,16 @@ local DEFAULT_HIGHLIGHTS = {
    GitHunkAdded = "Added",
    GitHunkChanged = "Changed",
    GitHunkRemoved = "Removed",
+    GitHunkHeader = "Statement",
+    GitHunkAnnotation = "Title",
    GitHunkAddLine = "DiffAdd",
    GitHunkDeleteLine = "DiffDelete",

    GitBlameAuthor = "GitAuthor",
    GitBlameDate = "GitDate",
    GitBlameSha = "GitSha",
+
+    GitPopupEnd = "NonText",
 }
 local STAGED_HUNK_HL = {
    GitHunkStagedAdded = "GitHunkAdded",
@@ -199,6 +199,226 @@ t.test("line popup shows the commit for the cursor line", function()
    t.truthy((lines[1] or ""):find("t", 1, true), "author shown")
 end)

+t.test("line popup appends the commit's hunk for the cursor line", function()
+    local dir = h.make_repo({ ["a.txt"] = "alpha\nbeta\ngamma\n" })
+    t.write(dir, "a.txt", "alpha\nBETA\ngamma\n")
+    h.git(dir, "add", "a.txt")
+    h.git(dir, "commit", "-q", "-m", "change beta")
+    vim.cmd.edit(dir .. "/a.txt")
+    local buf = vim.api.nvim_get_current_buf()
+    vim.api.nvim_win_set_cursor(0, { 2, 0 })
+    blame.line_popup(buf)
+    local float = wait_float()
+    t.defer(function()
+        pcall(vim.api.nvim_win_close, float, true)
+    end)
+    t.wait_for(function()
+        local lines = vim.api.nvim_buf_get_lines(
+            vim.api.nvim_win_get_buf(float),
+            0,
+            -1,
+            false
+        )
+        for _, l in ipairs(lines) do
+            if l:match("^@@") then
+                return true
+            end
+        end
+        return false
+    end, "hunk header to appear in the blame popup")
+    local lines = vim.api.nvim_buf_get_lines(
+        vim.api.nvim_win_get_buf(float),
+        0,
+        -1,
+        false
+    )
+    local has = {} ---@type table<string, boolean>
+    for _, l in ipairs(lines) do
+        has[l] = true
+    end
+    t.truthy(has["-beta"], "popup includes the pre-image of the changed line")
+    t.truthy(has["+BETA"], "popup includes the post-image of the changed line")
+    t.truthy(
+        has["Hunk 1 of 1"],
+        "popup annotates the hunk index even when the commit only has one"
+    )
+    local pbuf = vim.api.nvim_win_get_buf(float)
+    local seen = {} ---@type table<string, boolean>
+    for _, m in
+        ipairs(vim.api.nvim_buf_get_extmarks(pbuf, -1, 0, -1, {
+            details = true,
+        }))
+    do
+        local hl = m[4] and m[4].line_hl_group
+        if hl then
+            seen[hl] = true
+        end
+    end
+    t.truthy(seen["GitHunkAdded"], "+ line gets GitHunkAdded")
+    t.truthy(seen["GitHunkRemoved"], "- line gets GitHunkRemoved")
+    t.truthy(seen["GitHunkHeader"], "@@ header gets GitHunkHeader")
+    t.truthy(
+        seen["GitHunkAnnotation"],
+        "hunk-index annotation gets GitHunkAnnotation"
+    )
+end)
+
+t.test(
+    "line popup picks the hunk that contains the cursor, not the first one",
+    function()
+        local lines_initial = {}
+        local lines_changed = {}
+        for i = 1, 12 do
+            table.insert(lines_initial, "line" .. i)
+            table.insert(lines_changed, "line" .. i)
+        end
+        lines_changed[2] = "FIRST"
+        lines_changed[10] = "SECOND"
+        local initial = table.concat(lines_initial, "\n") .. "\n"
+        local changed = table.concat(lines_changed, "\n") .. "\n"
+        local dir = h.make_repo({ ["a.txt"] = initial })
+        t.write(dir, "a.txt", changed)
+        h.git(dir, "add", "a.txt")
+        h.git(dir, "commit", "-q", "-m", "change line 2 and line 10")
+        vim.cmd.edit(dir .. "/a.txt")
+        local buf = vim.api.nvim_get_current_buf()
+        vim.api.nvim_win_set_cursor(0, { 10, 0 })
+        blame.line_popup(buf)
+        local float = wait_float()
+        t.defer(function()
+            pcall(vim.api.nvim_win_close, float, true)
+        end)
+        t.wait_for(function()
+            for _, l in
+                ipairs(
+                    vim.api.nvim_buf_get_lines(
+                        vim.api.nvim_win_get_buf(float),
+                        0,
+                        -1,
+                        false
+                    )
+                )
+            do
+                if l == "+SECOND" then
+                    return true
+                end
+            end
+            return false
+        end, "popup to include the second hunk's added line")
+        local lines = vim.api.nvim_buf_get_lines(
+            vim.api.nvim_win_get_buf(float),
+            0,
+            -1,
+            false
+        )
+        local has = {} ---@type table<string, boolean>
+        for _, l in ipairs(lines) do
+            has[l] = true
+        end
+        t.truthy(has["-line10"], "popup includes second hunk pre-image")
+        t.truthy(has["+SECOND"], "popup includes second hunk post-image")
+        t.falsy(has["-line2"], "popup omits the first hunk's pre-image")
+        t.falsy(has["+FIRST"], "popup omits the first hunk's post-image")
+        t.truthy(
+            has["Hunk 2 of 2"],
+            "popup annotates which hunk is selected and how many total"
+        )
+    end
+)
+
+t.test(
+    "line popup finds the diff via the historical filename after a rename",
+    function()
+        local dir = h.make_repo({ ["old.txt"] = "alpha\nbeta\n" })
+        t.write(dir, "old.txt", "ALPHA\nbeta\n")
+        h.git(dir, "add", "old.txt")
+        h.git(dir, "commit", "-q", "-m", "change line 1")
+        h.git(dir, "mv", "old.txt", "new.txt")
+        h.git(dir, "commit", "-q", "-m", "rename")
+        vim.cmd.edit(dir .. "/new.txt")
+        local buf = vim.api.nvim_get_current_buf()
+        vim.api.nvim_win_set_cursor(0, { 1, 0 })
+        blame.line_popup(buf)
+        local float = wait_float()
+        t.defer(function()
+            pcall(vim.api.nvim_win_close, float, true)
+        end)
+        t.wait_for(function()
+            for _, l in
+                ipairs(
+                    vim.api.nvim_buf_get_lines(
+                        vim.api.nvim_win_get_buf(float),
+                        0,
+                        -1,
+                        false
+                    )
+                )
+            do
+                if l == "+ALPHA" then
+                    return true
+                end
+            end
+            return false
+        end, "popup to include the pre-rename commit's diff via old.txt")
+    end
+)
+
+t.test("line popup collapses a new-file diff to a single marker", function()
+    local dir = h.make_repo({ ["a.txt"] = "alpha\nbeta\ngamma\n" })
+    vim.cmd.edit(dir .. "/a.txt")
+    local buf = vim.api.nvim_get_current_buf()
+    vim.api.nvim_win_set_cursor(0, { 2, 0 })
+    blame.line_popup(buf)
+    local float = wait_float()
+    t.defer(function()
+        pcall(vim.api.nvim_win_close, float, true)
+    end)
+    t.wait_for(function()
+        for _, l in
+            ipairs(
+                vim.api.nvim_buf_get_lines(
+                    vim.api.nvim_win_get_buf(float),
+                    0,
+                    -1,
+                    false
+                )
+            )
+        do
+            if l == "(new file)" then
+                return true
+            end
+        end
+        return false
+    end, "popup to show the new-file marker")
+    local lines = vim.api.nvim_buf_get_lines(
+        vim.api.nvim_win_get_buf(float),
+        0,
+        -1,
+        false
+    )
+    for _, l in ipairs(lines) do
+        t.falsy(
+            vim.startswith(l, "+alpha")
+                or vim.startswith(l, "+beta")
+                or vim.startswith(l, "+gamma"),
+            "popup does not dump the file content as + lines"
+        )
+    end
+    local pbuf = vim.api.nvim_win_get_buf(float)
+    local seen = {} ---@type table<string, boolean>
+    for _, m in
+        ipairs(vim.api.nvim_buf_get_extmarks(pbuf, -1, 0, -1, {
+            details = true,
+        }))
+    do
+        local hl = m[4] and m[4].line_hl_group
+        if hl then
+            seen[hl] = true
+        end
+    end
+    t.truthy(seen["GitHunkAdded"], "new-file marker gets GitHunkAdded")
+end)
+
 t.test("re-invoking the line popup focuses the open float", function()
    local _, buf = setup("alpha\nbeta\n")
    vim.api.nvim_set_current_buf(buf)
@@ -608,6 +608,32 @@ t.test("preview_hunk shows the hunk body without file headers", function()
    end
 end)

+t.test("preview_hunk highlights diff lines via per-line extmarks", function()
+    local _, buf = setup("a\nb\nc\n", "a\nB\nc\n")
+    vim.api.nvim_set_current_buf(buf)
+    vim.api.nvim_win_set_cursor(0, { 2, 0 })
+    hunks.preview_hunk(buf)
+    local float = assert(find_float(), "preview float should open")
+    t.defer(function()
+        pcall(vim.api.nvim_win_close, float, true)
+    end)
+    local pbuf = vim.api.nvim_win_get_buf(float)
+    local seen = {} ---@type table<string, boolean>
+    for _, m in
+        ipairs(vim.api.nvim_buf_get_extmarks(pbuf, -1, 0, -1, {
+            details = true,
+        }))
+    do
+        local hl = m[4] and m[4].line_hl_group
+        if hl then
+            seen[hl] = true
+        end
+    end
+    t.truthy(seen["GitHunkHeader"], "@@ header gets GitHunkHeader")
+    t.truthy(seen["GitHunkAdded"], "+ line gets GitHunkAdded")
+    t.truthy(seen["GitHunkRemoved"], "- line gets GitHunkRemoved")
+end)
+
 t.test("preview_hunk re-invocation focuses the open float", function()
    local _, buf = setup("a\nb\nc\n", "a\nB\nc\n")
    vim.api.nvim_set_current_buf(buf)