fix: wrong parsing with leading spaces

Author: sergluka

lua/fix/document.lua

@@ -151,8 +151,9 @@ end
 
 ---@param buf number
 ---@param lnum number 0-based
+---@param line_text string
 ---@return TSNode|nil node, boolean covered  -- covered=false: the tree does not span lnum (stale/in-flight parse)
-local function message_node_at(buf, lnum)
+local function message_node_at(buf, lnum, line_text)
     local ok, parser = pcall(vim.treesitter.get_parser, buf, "fix")
     if not ok or not parser then
         error("No FIX parser for buffer " .. buf)
@@ -162,7 +163,9 @@ local function message_node_at(buf, lnum)
     if lnum > end_row or (lnum == end_row and end_col == 0) then
         return nil, false
     end
-    local node = root:descendant_for_range(lnum, 0, lnum, 0)
+    local first_nonblank = line_text:find("%S")
+    local col = first_nonblank and first_nonblank - 1 or 0
+    local node = root:descendant_for_range(lnum, col, lnum, col)
     while node and node:type() ~= "message" do
         node = node:parent()
     end
@@ -187,7 +190,7 @@ function M.build_line(buf, lnum, line_text, key)
 
     local semantic = Cache.get_semantic(key)
     if semantic == nil then
-        local node, covered = message_node_at(buf, lnum)
+        local node, covered = message_node_at(buf, lnum, line_text)
         if node then
             semantic = semantic_from_node(buf, node)
             Cache.put_semantic(key, semantic)

lua/fix/init.lua

@@ -6,9 +6,6 @@
 -- TODO: yank in picker
 -- TODO: highlight values based on Type
 
--- testing:
--- TODO: test with spaces at the start
-
 ---@class FixOpts
 ---@field ft? table
 ---@field ft.extensions? string[]

tests/integration/test_edge_cases.lua

@@ -59,6 +59,47 @@ T["duplicate tags render both extmarks"] = function()
     MiniTest.expect.equality(H.inline_label_count(nvim(), "Symbol"), 2)
 end
 
+T["message with leading spaces is annotated"] = function()
+    nvim().cmd("enew")
+    nvim().lua([[
+        vim.api.nvim_buf_set_lines(0, 0, -1, false, {
+            "   8=FIX.4.4|9=20|35=D|49=A|56=B|10=000|",
+        })
+    ]])
+    nvim().cmd("set filetype=fix")
+    H.wait_annotated(nvim())
+
+    H.expect_inline_label(nvim(), "BeginString")
+    H.expect_inline_label(nvim(), "NewOrderSingle")
+
+    local decoded = nvim().lua_get([[
+        (function()
+            local message = require("fix.document").build_line(0, 0)
+            if message == nil then
+                return nil
+            end
+            local first = message:list_fields()[1]
+            return {
+                version = message.version,
+                tag = first.tag,
+                tag_start = first.tag_start,
+                tag_end = first.tag_end,
+                value_start = first.value_start,
+                value_end = first.value_end,
+            }
+        end)()
+    ]])
+    MiniTest.expect.equality(decoded, {
+        version = "FIX.4.4",
+        tag = 8,
+        tag_start = 3,
+        tag_end = 4,
+        value_start = 5,
+        value_end = 12,
+    })
+    H.expect_no_error_notifications(nvim())
+end
+
 T["empty buffer produces no extmarks and no errors"] = function()
     H.load_fixture(nvim(), "empty.fix", { expect_extmarks = false, timeout_ms = 100 })
     MiniTest.expect.equality(#H.get_extmarks(nvim()), 0)