From 12b159118a67abf2c2d47492c6c502f5f5720d7f Mon Sep 17 00:00:00 2001
From: Jay Berkenbilt <ejb@ql.org>
Date: Sat, 20 Apr 2019 20:03:59 -0400
Subject: Compare versions between CLI and library

---
 ChangeLog            |  7 +++++++
 README-maintainer    |  1 +
 make_dist            | 22 ++++++++++++++++++++++
 qpdf/qpdf.cc         | 13 +++++++++++++
 qpdf/qtest/qpdf.test |  2 +-
 5 files changed, 44 insertions(+), 1 deletion(-)

diff --git a/ChangeLog b/ChangeLog
index 6ab197fc..66c82e4c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,12 @@
 2019-04-20  Jay Berkenbilt  <ejb@ql.org>
 
+	* When qpdf --version is run, it will detect if the qpdf CLI was
+	built with a different version of qpdf than the library. This
+	usually indicates that multiple versions of qpdf are installed and
+	that the library path is not set up properly. This situation
+	sometimes causes confusing behavior for users who are not actually
+	running the version of qpdf they think they are running.
+
 	* Add parameter --remove-page-labels to remove page labels from
 	output. In qpdf 8.3.0, the behavior changed so that page labels
 	were preserved when merging and splitting files. Some users were
diff --git a/README-maintainer b/README-maintainer
index 4b47a809..3ae29e90 100644
--- a/README-maintainer
+++ b/README-maintainer
@@ -103,6 +103,7 @@ RELEASE PREPARATION
   * configure.ac
   * libqpdf/QPDF.cc
   * manual/qpdf-manual.xml
+  * qpdf/qpdf.cc
   `make_dist` verifies this consistency.
 
 * Add a release entry to ChangeLog.
diff --git a/make_dist b/make_dist
index 1b8b095e..d6e42332 100755
--- a/make_dist
+++ b/make_dist
@@ -63,6 +63,7 @@ cd($tmpdir);
 my $config_version = get_version_from_configure();
 my $code_version = get_version_from_source();
 my $doc_version = get_version_from_manual();
+my $cli_version = get_version_from_cli();
 
 my $version_error = 0;
 if ($version ne $config_version)
@@ -80,6 +81,11 @@ if ($version ne $doc_version)
     print "$whoami: qpdf-manual.xml version = $doc_version\n";
     $version_error = 1;
 }
+if ($version ne $cli_version)
+{
+    print "$whoami: qpdf.cc version = $cli_version\n";
+    $version_error = 1;
+}
 if ($version_error)
 {
     die "$whoami: version numbers are not consistent\n";
@@ -161,6 +167,22 @@ sub get_version_from_manual
     $doc_version;
 }
 
+sub get_version_from_cli
+{
+    my $fh = safe_open("qpdf/qpdf.cc");
+    my $cli_version = 'unknown';
+    while (<$fh>)
+    {
+        if (m/expected_version = \"([^\"]+)\"/)
+        {
+            $cli_version = $1;
+            last;
+        }
+    }
+    $fh->close();
+    $cli_version;
+}
+
 sub safe_open
 {
     my $file = shift;
diff --git a/qpdf/qpdf.cc b/qpdf/qpdf.cc
index 495816c3..5bf36c5b 100644
--- a/qpdf/qpdf.cc
+++ b/qpdf/qpdf.cc
@@ -30,6 +30,8 @@ static int const EXIT_WARNING = 3;
 
 static char const* whoami = 0;
 
+static std::string expected_version = "8.4.0";
+
 struct PageSpec
 {
     PageSpec(std::string const& filename,
@@ -993,6 +995,17 @@ ArgParser::argPositional(char* arg)
 void
 ArgParser::argVersion()
 {
+    if (expected_version != QPDF::QPDFVersion())
+    {
+        std::cerr << "***\n"
+                  << "WARNING: qpdf CLI from version " << expected_version
+                  << " is using library version " << QPDF::QPDFVersion()
+                  << ".\n"
+                  << "This probably means you have multiple versions of qpdf installed\n"
+                  << "and don't have your library path configured correctly.\n"
+                  << "***"
+                  << std::endl;
+    }
     std::cout
         << whoami << " version " << QPDF::QPDFVersion() << std::endl
         << "Run " << whoami << " --copyright to see copyright and license information."
diff --git a/qpdf/qtest/qpdf.test b/qpdf/qtest/qpdf.test
index 6ee0ecfe..3eea8df3 100644
--- a/qpdf/qtest/qpdf.test
+++ b/qpdf/qtest/qpdf.test
@@ -667,7 +667,7 @@ $n_tests += 3;
 
 $td->runtest("qpdf version",
 	     {$td->COMMAND => "qpdf --version"},
-	     {$td->REGEXP => "qpdf version \\S+\n.*", $td->EXIT_STATUS => 0},
+	     {$td->REGEXP => ".*qpdf version \\S+\n.*", $td->EXIT_STATUS => 0},
 	     $td->NORMALIZE_NEWLINES);
 $td->runtest("qpdf copyright contains version too",
 	     {$td->COMMAND => "qpdf --copyright"},
-- 
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