Fix missing program from file

When jq is not supplied with a program, it usually exits with an error
and usage text, except for when jq is not connected to a TTY (i.e., not
interactive), in which case a default program of `.` is used. Combined
with `-f`, it then tries to read `.` as the filename.

    $ jq
    jq - commandline JSON processor [version 1.7.1]
    …
    $ jq -f
    jq - commandline JSON processor [version 1.7.1]
    …
    $ jq | cat
    ^C
    $ jq -f | cat
    jq: Could not open .: It's a directory

1 files changed, 1 insertions, 1 deletions

diff --git a/src/main.c b/src/main.c
index ccc73e9a..e2cae73a 100644
--- a/src/main.c
+++ b/src/main.c
@@ -587,7 +587,7 @@ int main(int argc, char* argv[]) {
     jq_set_attr(jq, jv_string("VERSION_DIR"), jv_string_fmt("%.*s-master", (int)(strchr(JQ_VERSION, '-') - JQ_VERSION), JQ_VERSION));
 
 #ifdef USE_ISATTY
-  if (!program && (!isatty(STDOUT_FILENO) || !isatty(STDIN_FILENO)))
+  if (!program && !(options & FROM_FILE) && (!isatty(STDOUT_FILENO) || !isatty(STDIN_FILENO)))
     program = ".";
 #endif