Ignore -- at the top level arg parser (fixes #652)

This was unintended behavior that was added back for backward
compatibility. It is intentionally undocumented.

4 files changed, 18 insertions, 3 deletions

diff --git a/ChangeLog b/ChangeLog
index b63a785d..894504c0 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,8 @@
 2022-02-15  Jay Berkenbilt  <ejb@ql.org>
 
+	* Bug fix: 10.6.0 inadvertently removed an unknown/undocumented
+	CLI parsing feature, which has been restored in 10.6.2. Fixes #652.
+
 	* Don't map 0x18 through 0x1f, 0x7f, 0x9f, or 0xad as fixed points
 	when transcoding UTF-8 to PDFDoc. These codepoints have different
 	meanings in those two encoding systems. Fixes #650.
diff --git a/libqpdf/QPDFArgParser.cc b/libqpdf/QPDFArgParser.cc
index 0e072c10..868db709 100644
--- a/libqpdf/QPDFArgParser.cc
+++ b/libqpdf/QPDFArgParser.cc
@@ -554,8 +554,7 @@ QPDFArgParser::parseArgs()
         bool have_parameter = false;
         std::string o_arg(arg);
         std::string arg_s(arg);
-        if ((strcmp(arg, "--") == 0) &&
-            (this->m->option_table != &this->m->main_option_table))
+        if (strcmp(arg, "--") == 0)
         {
             // Special case for -- option, which is used to break out
             // of subparsers.
diff --git a/libqpdf/QPDFJob_argv.cc b/libqpdf/QPDFJob_argv.cc
index 6cbbd841..b1e3da1c 100644
--- a/libqpdf/QPDFJob_argv.cc
+++ b/libqpdf/QPDFJob_argv.cc
@@ -67,6 +67,11 @@ ArgParser::initOptionTables()
     this->ap.addFinalCheck([this](){c_main->checkConfiguration();});
     // add_help is defined in auto_job_help.hh
     add_help(this->ap);
+    // Special case: ignore -- at the top level. This undocumented
+    // behavior is for backward compatibility; it was unintentionally
+    // the case prior to 10.6, and some users were relying on it.
+    this->ap.selectMainOptionTable();
+    this->ap.addBare("--", [](){});
 }
 
 void
diff --git a/qpdf/qtest/qpdf.test b/qpdf/qtest/qpdf.test
index ecc51bb8..14205d88 100644
--- a/qpdf/qtest/qpdf.test
+++ b/qpdf/qtest/qpdf.test
@@ -149,7 +149,7 @@ foreach my $c (@completion_tests)
 show_ntests();
 # ----------
 $td->notify("--- Argument Parsing ---");
-$n_tests += 12;
+$n_tests += 13;
 
 $td->runtest("required argument",
              {$td->COMMAND => "qpdf --password minimal.pdf"},
@@ -211,6 +211,14 @@ $td->runtest("duplicated pages password",
              {$td->REGEXP => ".*password already specified.*",
                   $td->EXIT_STATUS => 2},
              $td->NORMALIZE_NEWLINES);
+# Ignoring -- at the top level was never intended but turned out to
+# have been there for a long time so that people relied on it. It is
+# intentionally not documented.
+$td->runtest("ignore -- at top level",
+             {$td->COMMAND => "qpdf -- --check -- minimal.pdf --"},
+             {$td->REGEXP => ".*No syntax or stream encoding errors found.*",
+                  $td->EXIT_STATUS => 0},
+             $td->NORMALIZE_NEWLINES);
 
 show_ntests();
 # ----------