1 files changed, 31 insertions, 29 deletions

diff --git a/src/nvim/os/shell.c b/src/nvim/os/shell.c
index 9514936ad0..32e9a70e57 100644
--- a/src/nvim/os/shell.c
+++ b/src/nvim/os/shell.c
@@ -1,3 +1,6 @@
+// This is an open source non-commercial project. Dear PVS-Studio, please check
+// it. PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
+
 #include <string.h>
 #include <assert.h>
 #include <stdbool.h>
@@ -39,14 +42,15 @@ typedef struct {
 #endif
 
 /// Builds the argument vector for running the user-configured 'shell' (p_sh)
-/// with an optional command prefixed by 'shellcmdflag' (p_shcf).
+/// with an optional command prefixed by 'shellcmdflag' (p_shcf). E.g.:
+///
+///   ["shell", "-extra_args", "-shellcmdflag", "command with spaces"]
 ///
 /// @param cmd Command string, or NULL to run an interactive shell.
 /// @param extra_args Extra arguments to the shell, or NULL.
-/// @return A newly allocated argument vector. It must be freed with
-///         `shell_free_argv` when no longer needed.
+/// @return Newly allocated argument vector. Must be freed with shell_free_argv.
 char **shell_build_argv(const char *cmd, const char *extra_args)
-  FUNC_ATTR_NONNULL_RET FUNC_ATTR_MALLOC
+  FUNC_ATTR_NONNULL_RET
 {
   size_t argc = tokenize(p_sh, NULL) + (cmd ? tokenize(p_shcf, NULL) : 0);
   char **rv = xmalloc((argc + 4) * sizeof(*rv));
@@ -123,15 +127,9 @@ int os_call_shell(char_u *cmd, ShellOpts opts, char_u *extra_args)
   }
 
   size_t nread;
-
-  int status = do_os_system(shell_build_argv((char *)cmd, (char *)extra_args),
-                            input.data,
-                            input.len,
-                            output_ptr,
-                            &nread,
-                            emsg_silent,
-                            forward_output);
-
+  int exitcode = do_os_system(shell_build_argv((char *)cmd, (char *)extra_args),
+                              input.data, input.len, output_ptr, &nread,
+                              emsg_silent, forward_output);
   xfree(input.data);
 
   if (output) {
@@ -139,16 +137,16 @@ int os_call_shell(char_u *cmd, ShellOpts opts, char_u *extra_args)
     xfree(output);
   }
 
-  if (!emsg_silent && status != 0 && !(opts & kShellOptSilent)) {
+  if (!emsg_silent && exitcode != 0 && !(opts & kShellOptSilent)) {
     MSG_PUTS(_("\nshell returned "));
-    msg_outnum(status);
+    msg_outnum(exitcode);
     msg_putchar('\n');
   }
 
   State = current_state;
   signal_accept_deadly();
 
-  return status;
+  return exitcode;
 }
 
 /// os_system - synchronously execute a command in the shell
@@ -157,7 +155,7 @@ int os_call_shell(char_u *cmd, ShellOpts opts, char_u *extra_args)
 ///   char *output = NULL;
 ///   size_t nread = 0;
 ///   char *argv[] = {"ls", "-la", NULL};
-///   int status = os_sytem(argv, NULL, 0, &output, &nread);
+///   int exitcode = os_sytem(argv, NULL, 0, &output, &nread);
 ///
 /// @param argv The commandline arguments to be passed to the shell. `argv`
 ///             will be consumed.
@@ -218,11 +216,14 @@ static int do_os_system(char **argv,
   proc->in = input != NULL ? &in : NULL;
   proc->out = &out;
   proc->err = &err;
-  if (!process_spawn(proc)) {
+  int status = process_spawn(proc);
+  if (status) {
     loop_poll_events(&main_loop, 0);
-    // Failed, probably due to 'sh' not being executable
+    // Failed, probably 'shell' is not executable.
     if (!silent) {
-      MSG_PUTS(_("\nCannot execute "));
+      MSG_PUTS(_("\nshell failed to start: "));
+      msg_outtrans((char_u *)os_strerror(status));
+      MSG_PUTS(": ");
       msg_outtrans((char_u *)prog);
       msg_putchar('\n');
     }
@@ -262,7 +263,7 @@ static int do_os_system(char **argv,
   // busy state.
   ui_busy_start();
   ui_flush();
-  int status = process_wait(proc, -1, NULL);
+  int exitcode = process_wait(proc, -1, NULL);
   if (!got_int && out_data_decide_throttle(0)) {
     // Last chunk of output was skipped; display it now.
     out_data_ring(NULL, SIZE_MAX);
@@ -289,7 +290,7 @@ static int do_os_system(char **argv,
   assert(multiqueue_empty(events));
   multiqueue_free(events);
 
-  return status;
+  return exitcode;
 }
 
 ///  - ensures at least `desired` bytes in buffer
@@ -321,7 +322,7 @@ static void system_data_cb(Stream *stream, RBuffer *buf, size_t count,
 /// Tracks output received for the current executing shell command, and displays
 /// a pulsing "..." when output should be skipped. Tracking depends on the
 /// synchronous/blocking nature of ":!".
-//
+///
 /// Purpose:
 ///   1. CTRL-C is more responsive. #1234 #5396
 ///   2. Improves performance of :! (UI, esp. TUI, is the bottleneck).
@@ -446,7 +447,7 @@ static void out_data_append_to_screen(char *output, size_t remaining,
   size_t off = 0;
   int last_row = (int)Rows - 1;
 
-  while (off < remaining) {
+  while (output != NULL && off < remaining) {
     // Found end of line?
     if (output[off] == NL) {
       // Can we start a new line or do we need to continue the last one?
@@ -463,15 +464,16 @@ static void out_data_append_to_screen(char *output, size_t remaining,
       continue;
     }
 
-    // Translate NUL to SOH
-    if (output[off] == NUL) {
-      output[off] = 1;
+    // TODO(bfredl): using msg_puts would be better until
+    // terminal emulation is implemented.
+    if (output[off] < 0x20) {
+      output[off] = ' ';
     }
 
     off++;
   }
 
-  if (remaining) {
+  if (output != NULL && remaining) {
     if (last_col == 0) {
       screen_del_lines(0, 0, 1, (int)Rows, NULL);
     }
@@ -683,7 +685,7 @@ static void shell_write_cb(Stream *stream, void *data, int status)
                        uv_err_name(status));
   }
   if (stream->closed) {  // Process may have exited before this write.
-    ELOG("stream was already closed");
+    WLOG("stream was already closed");
     return;
   }
   stream_close(stream, NULL, NULL);