unittest: Allow multiple indirect includes

Works by saving all preprocessor defines and reusing them on each run. This also
saves NVIM_HEADER_H defines. Saving other defines is needed for defines like
`Map(foo, bar)` which are sometimes used to declare types or functions. Saving
types or function declarations is not needed because they are recorded as luajit
state.

Fixes #5857

5 files changed, 80 insertions, 56 deletions

diff --git a/test/functional/helpers.lua b/test/functional/helpers.lua
index f3332cff4f..d67f225ed1 100644
--- a/test/functional/helpers.lua
+++ b/test/functional/helpers.lua
@@ -21,6 +21,9 @@ local nvim_argv = {nvim_prog, '-u', 'NONE', '-i', 'NONE', '-N',
 
 local mpack = require('mpack')
 
+local tmpname = global_helpers.tmpname
+local uname = global_helpers.uname
+
 -- Formulate a path to the directory containing nvim.  We use this to
 -- help run test executables.  It helps to keep the tests working, even
 -- when the build is not in the default location.
@@ -334,44 +337,6 @@ local function write_file(name, text, dont_dedent)
   file:close()
 end
 
--- Tries to get platform name from $SYSTEM_NAME, uname; fallback is "Windows".
-local uname = (function()
-  local platform = nil
-  return (function()
-    if platform then
-      return platform
-    end
-
-    platform = os.getenv("SYSTEM_NAME")
-    if platform then
-      return platform
-    end
-
-    local status, f = pcall(io.popen, "uname -s")
-    if status then
-      platform = f:read("*l")
-    else
-      platform = 'Windows'
-    end
-    return platform
-  end)
-end)()
-
-local function tmpname()
-  local fname = os.tmpname()
-  if uname() == 'Windows' and fname:sub(1, 2) == '\\s' then
-    -- In Windows tmpname() returns a filename starting with
-    -- special sequence \s, prepend $TEMP path
-    local tmpdir = os.getenv('TEMP')
-    return tmpdir..fname
-  elseif fname:match('^/tmp') and uname() == 'Darwin' then
-    -- In OS X /tmp links to /private/tmp
-    return '/private'..fname
-  else
-    return fname
-  end
-end
-
 local function source(code)
   local fname = tmpname()
   write_file(fname, code)
diff --git a/test/helpers.lua b/test/helpers.lua
index 4c50c7644f..0bc62da5d7 100644
--- a/test/helpers.lua
+++ b/test/helpers.lua
@@ -52,9 +52,49 @@ local function check_logs()
   assert(0 == runtime_errors)
 end
 
+-- Tries to get platform name from $SYSTEM_NAME, uname; fallback is "Windows".
+local uname = (function()
+  local platform = nil
+  return (function()
+    if platform then
+      return platform
+    end
+
+    platform = os.getenv("SYSTEM_NAME")
+    if platform then
+      return platform
+    end
+
+    local status, f = pcall(io.popen, "uname -s")
+    if status then
+      platform = f:read("*l")
+    else
+      platform = 'Windows'
+    end
+    return platform
+  end)
+end)()
+
+local function tmpname()
+  local fname = os.tmpname()
+  if uname() == 'Windows' and fname:sub(1, 2) == '\\s' then
+    -- In Windows tmpname() returns a filename starting with
+    -- special sequence \s, prepend $TEMP path
+    local tmpdir = os.getenv('TEMP')
+    return tmpdir..fname
+  elseif fname:match('^/tmp') and uname() == 'Darwin' then
+    -- In OS X /tmp links to /private/tmp
+    return '/private'..fname
+  else
+    return fname
+  end
+end
+
 return {
   eq = eq,
   neq = neq,
   ok = ok,
   check_logs = check_logs,
+  uname = uname,
+  tmpname = tmpname,
 }
diff --git a/test/unit/formatc.lua b/test/unit/formatc.lua
index 00637e0b8d..9b47a318f0 100644
--- a/test/unit/formatc.lua
+++ b/test/unit/formatc.lua
@@ -219,12 +219,10 @@ local function standalone(...)  -- luacheck: ignore
   Preprocess.add_to_include_path('./../../build/include')
   Preprocess.add_to_include_path('./../../.deps/usr/include')
 
-  local input = Preprocess.preprocess_stream(arg[1])
-  local raw = input:read('*all')
-  input:close()
+  local raw = Preprocess.preprocess(arg[1])
 
   if raw == nil then
-    print("ERROR: Preprocess.preprocess_stream():read() returned empty")
+    print("ERROR: Preprocess.preprocess() returned empty")
   end
 
   local formatted
diff --git a/test/unit/helpers.lua b/test/unit/helpers.lua
index 3564f76442..c9885f73d0 100644
--- a/test/unit/helpers.lua
+++ b/test/unit/helpers.lua
@@ -68,14 +68,12 @@ local function cimport(...)
 
   local body = nil
   for _ = 1, 10 do
-    local stream = Preprocess.preprocess_stream(unpack(paths))
-    body = stream:read("*a")
-    stream:close()
+    body = Preprocess.preprocess(unpack(paths))
     if body ~= nil then break end
   end
 
   if body == nil then
-    print("ERROR: helpers.lua: Preprocess.preprocess_stream():read() returned empty")
+    print("ERROR: helpers.lua: Preprocess.preprocess() returned empty")
   end
 
   -- format it (so that the lines are "unique" statements), also filter out
diff --git a/test/unit/preprocess.lua b/test/unit/preprocess.lua
index 10ba997758..99537cd66a 100644
--- a/test/unit/preprocess.lua
+++ b/test/unit/preprocess.lua
@@ -1,8 +1,12 @@
 -- helps managing loading different headers into the LuaJIT ffi. Untested on
 -- windows, will probably need quite a bit of adjustment to run there.
 
+local global_helpers = require('test.helpers')
+
 local ffi = require("ffi")
 
+local tmpname = global_helpers.tmpname
+
 local ccs = {}
 
 local env_cc = os.getenv("CC")
@@ -61,12 +65,12 @@ end
 -- will produce a string that represents a meta C header file that includes
 -- all the passed in headers. I.e.:
 --
--- headerize({"stdio.h", "math.h", true}
+-- headerize({"stdio.h", "math.h"}, true)
 -- produces:
 -- #include <stdio.h>
 -- #include <math.h>
 --
--- headerize({"vim.h", "memory.h", false}
+-- headerize({"vim.h", "memory.h"}, false)
 -- produces:
 -- #include "vim.h"
 -- #include "memory.h"
@@ -79,8 +83,7 @@ local function headerize(headers, global)
   end
 
   local formatted = {}
-  for i = 1, #headers do
-    local hdr = headers[i]
+  for i, hdr in ipairs(headers) do
     formatted[#formatted + 1] = "#include " ..
                                 tostring(pre) ..
                                 tostring(hdr) ..
@@ -111,7 +114,8 @@ local Gcc = {
    '-D "_Nullable="',
    '-D "_Nonnull="',
    '-U__BLOCKS__',
-  }
+  },
+  added_header_defines = '',
 }
 
 function Gcc:new(obj)
@@ -145,21 +149,40 @@ end
 
 -- returns a stream representing a preprocessed form of the passed-in headers.
 -- Don't forget to close the stream by calling the close() method on it.
-function Gcc:preprocess_stream(...)
+function Gcc:preprocess(...)
   -- create pseudo-header
   local pseudoheader = headerize({...}, false)
+  local pseudoheader_fname = 'tmp_pseudoheader.h'
+  local pseudoheader_file = io.open(pseudoheader_fname, 'w')
+  pseudoheader_file:write(self.added_header_defines)
+  pseudoheader_file:write("\n")
+  pseudoheader_file:write(pseudoheader)
+  pseudoheader_file:flush()
+  pseudoheader_file:close()
   local defines = table.concat(self.preprocessor_extra_flags, ' ')
   local cmd = ("echo $hdr | " ..
                tostring(self.path) ..
                " " ..
                tostring(defines) ..
-               " -std=c99 -P -E -"):gsub('$hdr', shell_quote(pseudoheader))
+               " -std=c99 -P -E " .. shell_quote(pseudoheader_fname))
+  local def_cmd = ("echo $hdr | " ..
+                   tostring(self.path) ..
+                   " " ..
+                   tostring(defines) ..
+                   " -std=c99 -dM -E " .. shell_quote(pseudoheader_fname))
+  local def_stream = io.popen(def_cmd)
+  self.added_header_defines = def_stream:read('*a')
+  def_stream:close()
   -- lfs = require("lfs")
   -- print("CWD: #{lfs.currentdir!}")
   -- print("CMD: #{cmd}")
   -- io.stderr\write("CWD: #{lfs.currentdir!}\n")
   -- io.stderr\write("CMD: #{cmd}\n")
-  return io.popen(cmd)
+  local stream = io.popen(cmd)
+  local ret = stream:read('*a')
+  stream:close()
+  os.remove(pseudoheader_fname)
+  return ret
 end
 
 local Clang = Gcc:new()
@@ -197,8 +220,8 @@ return {
   includes = function(hdr)
     return cc:dependencies(hdr)
   end,
-  preprocess_stream = function(...)
-    return cc:preprocess_stream(...)
+  preprocess = function(...)
+    return cc:preprocess(...)
   end,
   add_to_include_path = function(...)
     return cc:add_to_include_path(...)