improve error message of ExecError when called command exited with no…

…n-zero status

src/constant.h

@@ -216,7 +216,8 @@ constexpr const char *TYPE_FUNC = "Func";
 constexpr unsigned int UDC_PARAM_ATTR = 0;  // &&attr
 constexpr unsigned int UDC_PARAM_REDIR = 1; // &&redir
 constexpr unsigned int UDC_PARAM_ARGV = 2;  // @
-constexpr unsigned int UDC_PARAM_N = UDC_PARAM_ARGV + 1;
+constexpr unsigned int UDC_PARAM_ARG0 = 3;  // 0
+constexpr unsigned int UDC_PARAM_N = UDC_PARAM_ARG0;
 
 // =====  termination kind  =====
 

src/vm.cpp

@@ -906,9 +906,11 @@ static void traceCmd(const ARState &state, const ArrayObject &argv) {
   errno = 0; // ignore error
 }
 
-static bool checkCmdExecError(ARState &state, CmdCallAttr attr, int64_t status) {
+static bool checkCmdExecError(ARState &state, StringRef cmdName, CmdCallAttr attr, int64_t status) {
   if (status != 0 && hasFlag(attr, CmdCallAttr::RAISE) && state.has(RuntimeOption::ERR_RAISE)) {
-    std::string message = "command exits with non-zero status: `";
+    std::string message = "`";
+    appendAsPrintable(cmdName, SYS_LIMIT_ERROR_MSG_MAX, message);
+    message += "' command exits with non-zero status: `";
     message += std::to_string(status);
     message += "'";
     raiseError(state, TYPE::ExecError, std::move(message), status);
@@ -940,13 +942,14 @@ bool VM::callCommand(ARState &state, const ResolvedCmd &cmd, ObjPtr<ArrayObject>
                                          std::move(redirConfig), attr);
   case ResolvedCmd::BUILTIN: {
     errno = 0;
+    const auto cmdName = array.getValues()[0];
     const int status = cmd.builtinCmd()(state, array);
     flushStdFD();
     if (state.hasError()) {
       return false;
     }
     pushExitStatus(state, status); // set exit status before check ERR_RAISE
-    if (!checkCmdExecError(state, attr, status)) {
+    if (!checkCmdExecError(state, cmdName.asStrRef(), attr, status)) {
       return false;
     }
     return true;
@@ -972,7 +975,7 @@ bool VM::callCommand(ARState &state, const ResolvedCmd &cmd, ObjPtr<ArrayObject>
       const bool ret = forkAndExec(state, cmd.filePath(), array, std::move(redirConfig));
       if (ret) {
         const int status = state.getMaskedExitStatus();
-        if (!checkCmdExecError(state, attr, status)) {
+        if (!checkCmdExecError(state, array.getValues()[0].asStrRef(), attr, status)) {
           return false;
         }
       }
@@ -1205,9 +1208,10 @@ int VM::builtinExec(ARState &state, ArrayObject &argvObj, Value &&redir) {
 
 bool VM::returnFromUserDefinedCommand(ARState &state, int64_t status) {
   const auto attr = static_cast<CmdCallAttr>(state.stack.getLocal(UDC_PARAM_ATTR).asNum());
+  const auto arg0 = state.stack.getLocal(UDC_PARAM_ARG0);
   state.stack.unwind();
   pushExitStatus(state, status); // set exit status before check ERR_RAISE
-  if (!checkCmdExecError(state, attr, status)) {
+  if (!checkCmdExecError(state, arg0.asStrRef(), attr, status)) {
     return false;
   }
   assert(!state.stack.checkVMReturn());
@@ -2075,12 +2079,13 @@ bool VM::mainLoop(ARState &state) {
         auto attr = static_cast<CmdCallAttr>(v);
         Value redir = state.stack.getLocal(UDC_PARAM_REDIR);
         auto argv = toObjPtr<ArrayObject>(state.stack.getLocal(UDC_PARAM_ARGV));
+        const auto arg0 = argv->getValues()[0];
         const auto ret = builtinCommand(state, std::move(argv), std::move(redir), attr);
         flushStdFD();
         if (ret.kind == BuiltinCmdResult::CALL) {
           TRY(ret.r);
         } else {
-          TRY(checkCmdExecError(state, attr, ret.status));
+          TRY(checkCmdExecError(state, arg0.asStrRef(), attr, ret.status));
           pushExitStatus(state, ret.status);
         }
         vmnext;
@@ -2106,9 +2111,10 @@ bool VM::mainLoop(ARState &state) {
         auto v = state.stack.getLocal(UDC_PARAM_ATTR).asNum();
         const auto attr = static_cast<CmdCallAttr>(v);
         Value redir = state.stack.getLocal(UDC_PARAM_REDIR);
-        auto argv = state.stack.getLocal(UDC_PARAM_ARGV);
-        int status = builtinExec(state, typeAs<ArrayObject>(argv), std::move(redir));
-        TRY(checkCmdExecError(state, attr, status));
+        auto &argv = typeAs<ArrayObject>(state.stack.getLocal(UDC_PARAM_ARGV));
+        const auto arg0 = argv.getValues()[0];
+        int status = builtinExec(state, argv, std::move(redir));
+        TRY(checkCmdExecError(state, arg0.asStrRef(), attr, status));
         pushExitStatus(state, status);
         vmnext;
       }
@@ -2154,7 +2160,7 @@ bool VM::mainLoop(ARState &state) {
         Value arg0;
         if (frame) {
           unsigned int localOffset = frame->localVarOffset;
-          arg0 = state.stack.unsafeGetOperand(localOffset + UDC_PARAM_N);
+          arg0 = state.stack.unsafeGetOperand(localOffset + UDC_PARAM_ARG0);
         } else {
           arg0 = state.getGlobal(BuiltinVarOffset::POS_0);
         }

test/exec/cases/base/errraise4.ds

@@ -7,21 +7,25 @@ var ex = 34 as Any
 try { command -W; } catch e { $ex = $e; }
 assert ($ex as ExecError).status() == 2
 assert ($ex as ExecError).lineno() == 7
+assert ($ex as ExecError).message() == "\`command' command exits with non-zero status: \`2'"
 
 $ex = 34
 try { command -V fjreifae; } catch e { $ex = $e; }
 assert ($ex as ExecError).status() == 1
-assert ($ex as ExecError).lineno() == 12
+assert ($ex as ExecError).lineno() == 13
+assert ($ex as ExecError).message() == "\`command' command exits with non-zero status: \`1'"
 
 ## exec
 $ex = 45
 try { exec -T; } catch e { $ex = $e; }
 assert ($ex as ExecError).status() == 2
-assert ($ex as ExecError).lineno() == 18
+assert ($ex as ExecError).lineno() == 20
+assert ($ex as ExecError).message() == "\`exec' command exits with non-zero status: \`2'"
 
 $ex = 45
 try { exec $'ls\x00'; } catch e { $ex = $e; }
 assert ($ex as ExecError).status() == 1
-assert ($ex as ExecError).lineno() == 23
+assert ($ex as ExecError).lineno() == 26
+assert ($ex as ExecError).message() == "\`exec' command exits with non-zero status: \`1'"
 
 true

test/exec/cases/base/errraise5.ds

@@ -8,7 +8,7 @@ try {
     ls | for a in $STDIN { 
         sh -c 'exit 56'; echo $a; }
 } catch e { $ex = $e; }
-assert ($ex as ExecError).message() == "command exits with non-zero status: \`56'"
+assert ($ex as ExecError).message() == "\`sh' command exits with non-zero status: \`56'"
 assert ($ex as ExecError).lineno() == 9
 
 assert $? == 0
@@ -23,7 +23,7 @@ try {
         sh -c 'exit 156'; echo $a; } | {
              false; }
 } catch e { $ex = $e; }
-assert ($ex as ExecError).message() == "command exits with non-zero status: \`1'"
+assert ($ex as ExecError).message() == "\`false' command exits with non-zero status: \`1'"
 assert ($ex as ExecError).lineno() == 24
 
 assert $? == 0
@@ -40,7 +40,7 @@ try {
         ff 67; echo $a; } | { 
             ff 145; }
 } catch e { $ex = $e; }
-assert ($ex as ExecError).message() == "command exits with non-zero status: \`145'"
+assert ($ex as ExecError).message() == "\`ff' command exits with non-zero status: \`145'"
 assert ($ex as ExecError).lineno() == 41
 
 assert $? == 0

test/exec/cases/output/try_finally_except1.ds

@@ -103,7 +103,7 @@ assert $({
 
 # CHECKERR: [warning at subshell=1]
 # CHECKERR: the following exception within finally/defer block is ignored
-# CHECKERR: ExecError: command exits with non-zero status: `1'
+# CHECKERR: ExecError: `false' command exits with non-zero status: `1'
 # CHECKERR_RE:     from .+/test/exec/cases/output/try_finally_except1\.ds:99 '<toplevel>\(\)'
 # CHECKERR_RE: ^$
 # CHECKERR: [runtime error at subshell=1]