feat(lua): execute stdin ("-") as Lua

5 files changed, 102 insertions, 28 deletions

diff --git a/runtime/doc/starting.txt b/runtime/doc/starting.txt
index 8dd083e4a3..fa9e23eb00 100644
--- a/runtime/doc/starting.txt
+++ b/runtime/doc/starting.txt
@@ -236,9 +236,10 @@ argument.
 <		This loads Lua module "bar" before executing "foo.lua": >
 			nvim +"lua require('bar')" -l foo.lua
 <
-		User |config| is skipped unless |-u| was given.
-		User |shada| is skipped unless |-i| was given.
-		Swap file is skipped (like |-n|).
+		Skips user |config| unless |-u| was given.
+		Disables plugins unless 'loadplugins' was set.
+		Disables |shada| unless |-i| was given.
+		Disables swapfile (like |-n|).
 
 							*-b*
 -b		Binary mode.  File I/O will only recognize <NL> to separate
diff --git a/src/nvim/README.md b/src/nvim/README.md
index e710c3ef58..6876227e48 100644
--- a/src/nvim/README.md
+++ b/src/nvim/README.md
@@ -18,6 +18,12 @@ The source files use extensions to hint about their purpose.
 - `*.h.generated.h` - exported functions’ declarations.
 - `*.c.generated.h` - static functions’ declarations.
 
+Common structures
+-----------------
+
+- StringBuilder
+- kvec or garray.c for dynamic lists / vectors (use StringBuilder for strings)
+
 Logs
 ----
 
diff --git a/src/nvim/lua/executor.c b/src/nvim/lua/executor.c
index 4b08603dd0..b7844363c5 100644
--- a/src/nvim/lua/executor.c
+++ b/src/nvim/lua/executor.c
@@ -335,7 +335,7 @@ static int nlua_thr_api_nvim__get_runtime(lua_State *lstate)
 /// @see https://github.com/premake/premake-core/blob/1c1304637f4f5e50ba8c57aae8d1d80ec3b7aaf2/src/host/premake.c#L563-L594
 ///
 /// @returns number of args
-int nlua_set_argv(char **argv, int argc, int lua_arg0)
+int nlua_init_argv(char **argv, int argc, int lua_arg0)
 {
   lua_State *const L = global_lstate;
   lua_newtable(L);  // _G.arg
@@ -1711,21 +1711,62 @@ void ex_luafile(exarg_T *const eap)
   nlua_exec_file((const char *)eap->arg);
 }
 
-/// Executes Lua code from a file.
+/// Executes Lua code from a file or "-" (stdin).
 ///
-/// Note: we call the Lua global loadfile as opposed to calling luaL_loadfile
-/// in case loadfile was overridden in the user's environment.
+/// Calls the Lua `loadfile` global as opposed to `luaL_loadfile` in case `loadfile` was overridden
+/// in the user environment.
 ///
-/// @param  path  path of the file
+/// @param path Path to the file, may be "-" (stdin) during startup.
 ///
-/// @return  true if everything ok, false if there was an error (echoed)
+/// @return true on success, false on error (echoed) or user canceled (CTRL-c) while reading "-"
+/// (stdin).
 bool nlua_exec_file(const char *path)
   FUNC_ATTR_NONNULL_ALL
 {
   lua_State *const lstate = global_lstate;
+  if (!strequal(path, "-")) {
+    lua_getglobal(lstate, "loadfile");
+    lua_pushstring(lstate, path);
+  } else {
+    int error;
+    int stdin_dup_fd;
+    if (stdin_fd > 0) {
+      stdin_dup_fd = stdin_fd;
+    } else {
+      stdin_dup_fd = os_dup(STDIN_FILENO);
+#ifdef MSWIN
+      // Replace the original stdin with the console input handle.
+      os_replace_stdin_to_conin();
+#endif
+    }
+    FileDescriptor *const stdin_dup = file_open_fd_new(&error, stdin_dup_fd,
+                                                       kFileReadOnly|kFileNonBlocking);
+    assert(stdin_dup != NULL);
+
+    StringBuilder sb = KV_INITIAL_VALUE;
+    kv_resize(sb, 64);
+    ptrdiff_t read_size = -1;
+    // Read all input from stdin, unless interrupted (ctrl-c).
+    while (true) {
+      if (got_int) {  // User canceled.
+        return false;
+      }
+      read_size = file_read(stdin_dup, IObuff, 64);
+      if (read_size < 0) {  // Error.
+        return false;
+      }
+      kv_concat_len(sb, IObuff, (size_t)read_size);
+      if (read_size < 64) {  // EOF.
+        break;
+      }
+    }
+    kv_push(sb, NUL);
+    file_free(stdin_dup, false);
 
-  lua_getglobal(lstate, "loadfile");
-  lua_pushstring(lstate, path);
+    lua_getglobal(lstate, "loadstring");
+    lua_pushstring(lstate, sb.items);
+    kv_destroy(sb);
+  }
 
   if (nlua_pcall(lstate, 1, 2)) {
     nlua_error(lstate, _("E5111: Error calling lua: %.*s"));
diff --git a/src/nvim/main.c b/src/nvim/main.c
index 616cf1b4b6..f0ce26d1bc 100644
--- a/src/nvim/main.c
+++ b/src/nvim/main.c
@@ -280,7 +280,7 @@ int main(int argc, char **argv)
   command_line_scan(&params);
 
   nlua_init();
-  nlua_set_argv(argv, argc, params.lua_arg0);
+  nlua_init_argv(argv, argc, params.lua_arg0);
   TIME_MSG("init lua interpreter");
 
   if (embedded_mode) {
diff --git a/test/functional/core/startup_spec.lua b/test/functional/core/startup_spec.lua
index 455de08548..d7e64c6b54 100644
--- a/test/functional/core/startup_spec.lua
+++ b/test/functional/core/startup_spec.lua
@@ -88,18 +88,18 @@ describe('startup', function()
   end)
 
   describe('-l Lua', function()
-    local function assert_l_out(expected, nvim_args, lua_args)
-      local args = { nvim_prog, '--clean' }
+    local function assert_l_out(expected, nvim_args, lua_args, script, input)
+      local args = { nvim_prog }
       vim.list_extend(args, nvim_args or {})
-      vim.list_extend(args, { '-l', 'test/functional/fixtures/startup.lua' })
+      vim.list_extend(args, { '-l', (script or 'test/functional/fixtures/startup.lua') })
       vim.list_extend(args, lua_args or {})
-      local out = funcs.system(args):gsub('\r\n', '\n')
+      local out = funcs.system(args, input):gsub('\r\n', '\n')
       return eq(dedent(expected), out)
     end
 
     it('failure modes', function()
-      -- nvim -l <missing file>
-      matches('nvim: Argument missing after: "%-l"', funcs.system({ nvim_prog, '-l' }))
+      -- nvim -l <empty>
+      matches('nvim%.?e?x?e?: Argument missing after: "%-l"', funcs.system({ nvim_prog, '-l' }))
       eq(1, eval('v:shell_error'))
     end)
 
@@ -107,7 +107,7 @@ describe('startup', function()
       -- nvim -l foo.lua -arg1 -- a b c
       assert_l_out([[
           bufs:
-          nvim args: 8
+          nvim args: 7
           lua args: { "-arg1", "--exitcode", "73", "--arg2" }]],
         {},
         { '-arg1', "--exitcode", "73", '--arg2' }
@@ -115,18 +115,35 @@ describe('startup', function()
       eq(73, eval('v:shell_error'))
     end)
 
-    it('Lua error sets Nvim exitcode', function()
+    it('Lua-error sets Nvim exitcode', function()
       eq(0, eval('v:shell_error'))
       matches('E5113: .* my pearls!!',
         funcs.system({ nvim_prog, '-l', 'test/functional/fixtures/startup-fail.lua' }))
       eq(1, eval('v:shell_error'))
+      matches('E5113: .* %[string "error%("whoa"%)"%]:1: whoa',
+        funcs.system({ nvim_prog, '-l', '-' }, 'error("whoa")'))
+      eq(1, eval('v:shell_error'))
+    end)
+
+    it('executes stdin "-"', function()
+      assert_l_out('args=2 whoa',
+        nil,
+        { 'arg1', 'arg 2' },
+        '-',
+        "print(('args=%d %s'):format(#_G.arg, 'whoa'))")
+      assert_l_out('biiig input: 1000042',
+        nil,
+        nil,
+        '-',
+        ('print("biiig input: "..("%s"):len())'):format(string.rep('x', (1000 * 1000) + 42)))
+      eq(0, eval('v:shell_error'))
     end)
 
     it('sets _G.arg', function()
       -- nvim -l foo.lua -arg1 -- a b c
       assert_l_out([[
           bufs:
-          nvim args: 7
+          nvim args: 6
           lua args: { "-arg1", "--arg2", "arg3" }]],
         {},
         { '-arg1', '--arg2', 'arg3' }
@@ -136,7 +153,7 @@ describe('startup', function()
       -- nvim -l foo.lua --
       assert_l_out([[
           bufs:
-          nvim args: 5
+          nvim args: 4
           lua args: { "--" }]],
         {},
         { '--' }
@@ -146,7 +163,7 @@ describe('startup', function()
       -- nvim file1 file2 -l foo.lua -arg1 -- file3 file4
       assert_l_out([[
           bufs: file1 file2
-          nvim args: 11
+          nvim args: 10
           lua args: { "-arg1", "arg 2", "--", "file3", "file4" }]],
         { 'file1', 'file2', },
         { '-arg1', 'arg 2', '--', 'file3', 'file4' }
@@ -156,7 +173,7 @@ describe('startup', function()
       -- nvim file1 file2 -l foo.lua -arg1 --
       assert_l_out([[
           bufs: file1 file2
-          nvim args: 8
+          nvim args: 7
           lua args: { "-arg1", "--" }]],
         { 'file1', 'file2', },
         { '-arg1', '--' }
@@ -166,7 +183,7 @@ describe('startup', function()
       -- nvim -l foo.lua <vim args>
       assert_l_out([[
           bufs:
-          nvim args: 6
+          nvim args: 5
           lua args: { "-c", "set wrap?" }]],
         {},
         { '-c', 'set wrap?' }
@@ -180,13 +197,22 @@ describe('startup', function()
             wrap
           
           bufs:
-          nvim args: 8
+          nvim args: 7
           lua args: { "-c", "set wrap?" }]],
         { '-c', 'set wrap?' },
         { '-c', 'set wrap?' }
       )
       eq(0, eval('v:shell_error'))
     end)
+
+    it('disables swapfile/shada/config/plugins', function()
+      assert_l_out('updatecount=0 shadafile=NONE loadplugins=false scriptnames=1',
+        nil,
+        nil,
+        '-',
+        [[print(('updatecount=%d shadafile=%s loadplugins=%s scriptnames=%d'):format(
+          vim.o.updatecount, vim.o.shadafile, tostring(vim.o.loadplugins), math.max(1, #vim.fn.split(vim.fn.execute('scriptnames'),'\n'))))]])
+    end)
   end)
 
   it('pipe at both ends: has("ttyin")==0 has("ttyout")==0', function()
@@ -375,11 +401,11 @@ describe('startup', function()
   it('-es/-Es disables swapfile, user config #8540', function()
     for _,arg in ipairs({'-es', '-Es'}) do
       local out = funcs.system({nvim_prog, arg,
-                                '+set swapfile? updatecount? shada?',
+                                '+set swapfile? updatecount? shadafile?',
                                 "+put =execute('scriptnames')", '+%print'})
       local line1 = string.match(out, '^.-\n')
       -- updatecount=0 means swapfile was disabled.
-      eq("  swapfile  updatecount=0  shada=!,'100,<50,s10,h\n", line1)
+      eq("  swapfile  updatecount=0  shadafile=\n", line1)
       -- Standard plugins were loaded, but not user config.
       eq('health.vim', string.match(out, 'health.vim'))
       eq(nil, string.match(out, 'init.vim'))