Disallow --empty with --replace-input (fixes #728)

2 files changed, 14 insertions, 1 deletions

diff --git a/libqpdf/QPDFJob.cc b/libqpdf/QPDFJob.cc
index 691f193c..8bf619a2 100644
--- a/libqpdf/QPDFJob.cc
+++ b/libqpdf/QPDFJob.cc
@@ -683,7 +683,13 @@ QPDFJob::getExitCode() const
 void
 QPDFJob::checkConfiguration()
 {
+    // Do final checks for command-line consistency. (I always think
+    // this is called doFinalChecks, so I'm putting that in a
+    // comment.)
+
     if (m->replace_input) {
+        // Check for --empty appears later after we have checked
+        // m->infilename.
         if (m->outfilename) {
             usage("--replace-input may not be used when"
                   " an output file is specified");
@@ -700,6 +706,8 @@ QPDFJob::checkConfiguration()
     }
     if (m->infilename == nullptr) {
         usage("an input file name is required");
+    } else if (m->replace_input && (strlen(m->infilename.get()) == 0)) {
+        usage("--replace-input may not be used with --empty");
     } else if (
         m->require_outfile && (m->outfilename == nullptr) &&
         (!m->replace_input)) {
diff --git a/qpdf/qtest/arg-parsing.test b/qpdf/qtest/arg-parsing.test
index 99c48b27..ad6bc0d2 100644
--- a/qpdf/qtest/arg-parsing.test
+++ b/qpdf/qtest/arg-parsing.test
@@ -15,7 +15,7 @@ cleanup();
 
 my $td = new TestDriver('arg-parsing');
 
-my $n_tests = 16;
+my $n_tests = 17;
 
 $td->runtest("required argument",
              {$td->COMMAND => "qpdf --password minimal.pdf"},
@@ -102,6 +102,11 @@ $td->runtest("ignore -- at top level",
              {$td->REGEXP => ".*No syntax or stream encoding errors found.*",
                   $td->EXIT_STATUS => 0},
              $td->NORMALIZE_NEWLINES);
+$td->runtest("empty and replace-input",
+             {$td->COMMAND => "qpdf --empty --replace-input"},
+             {$td->REGEXP => ".*--replace-input may not be used with --empty.*",
+                  $td->EXIT_STATUS => 2},
+             $td->NORMALIZE_NEWLINES);
 
 cleanup();
 $td->report($n_tests);