run-command: report exec error even on ENOENT

If execve(2) fails with ENOENT and we report the error, we use the
format "cannot run %s", followed by the actual error message.  For other
errors we use "cannot exec '%s'".

Stop making this subtle distinction and use the second format for all
execve(2) errors.  This simplifies the code and makes the prefix more
precise by indicating the failed operation.  It also allows us to
slightly simplify t1800.16.

On Windows -- which lacks execve(2) -- we already use a single format in
all cases: "cannot spawn %s".

Signed-off-by: René Scharfe <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: rscharfe

run-command.c

@@ -301,7 +301,6 @@ enum child_errcode {
 	CHILD_ERR_DUP2,
 	CHILD_ERR_CLOSE,
 	CHILD_ERR_SIGPROCMASK,
-	CHILD_ERR_ENOENT,
 	CHILD_ERR_SILENT,
 	CHILD_ERR_ERRNO
 };
@@ -384,9 +383,6 @@ static void child_err_spew(struct child_process *cmd, struct child_err *cerr)
 	case CHILD_ERR_SIGPROCMASK:
 		error_errno("sigprocmask failed restoring signals");
 		break;
-	case CHILD_ERR_ENOENT:
-		error_errno("cannot run %s", cmd->args.v[0]);
-		break;
 	case CHILD_ERR_SILENT:
 		break;
 	case CHILD_ERR_ERRNO:
@@ -840,13 +836,9 @@ int start_command(struct child_process *cmd)
 			execve(argv.v[0], (char *const *) argv.v,
 			       (char *const *) childenv);
 
-		if (errno == ENOENT) {
-			if (cmd->silent_exec_failure)
-				child_die(CHILD_ERR_SILENT);
-			child_die(CHILD_ERR_ENOENT);
-		} else {
-			child_die(CHILD_ERR_ERRNO);
-		}
+		if (cmd->silent_exec_failure && errno == ENOENT)
+			child_die(CHILD_ERR_SILENT);
+		child_die(CHILD_ERR_ERRNO);
 	}
 	atfork_parent(&as);
 	if (cmd->pid < 0)

t/t1800-hook.sh

@@ -164,7 +164,7 @@ test_expect_success 'git hook run a hook with a bad shebang' '
 	# TODO: We should emit the same (or at least a more similar)
 	# error on MINGW (essentially Git for Windows) and all other
 	# platforms.. See the OS-specific code in start_command()
-	grep -E "^(error|fatal): cannot (exec|run|spawn) .*bad-hooks/test-hook" err
+	grep -E "^(error|fatal): cannot (exec|spawn) .*bad-hooks/test-hook" err
 '
 
 test_expect_success 'stdin to hooks' '