Reject conflicting entries in run::bind

If there is more than one permuation of source and/or options in a 'bind'
entry, reject the configuration.

Change-Id: I4cd23b842470fe6abc4fbda64fdf23d1b2ea153c

ci/test.py

@@ -608,6 +608,58 @@ def test_malformed_bind_dest(self):
         s = self.assertPyrexContainerShellCommand("true", capture=True, returncode=1)
         self.assertIn("Error: too many colons in run.bind entry '%s'." % b, s)
 
+    def test_duplicate_bind(self):
+        temp_dir = tempfile.mkdtemp("-pyrex")
+        self.addCleanup(shutil.rmtree, temp_dir)
+
+        conf = self.get_config()
+        conf["run"]["bind"] += " %s" % (temp_dir)
+        conf["run"]["bind"] += " %s" % (temp_dir)
+        conf.write_conf()
+
+        self.assertPyrexContainerShellCommand(
+            "test -e {dir}".format(dir=temp_dir), returncode=0
+        )
+
+    def test_equivalent_bind(self):
+        temp_dir = tempfile.mkdtemp("-pyrex")
+        self.addCleanup(shutil.rmtree, temp_dir)
+
+        conf = self.get_config()
+        conf["run"]["bind"] += " %s" % (temp_dir)
+        conf["run"]["bind"] += " %s:%s" % (temp_dir, temp_dir)
+        conf.write_conf()
+
+        self.assertPyrexContainerShellCommand(
+            "test -e {dir}".format(dir=temp_dir), returncode=0
+        )
+
+    def test_conflicting_bind_sources(self):
+        temp_dir1 = tempfile.mkdtemp("-pyrex")
+        self.addCleanup(shutil.rmtree, temp_dir1)
+
+        temp_dir2 = tempfile.mkdtemp("-pyrex")
+        self.addCleanup(shutil.rmtree, temp_dir2)
+
+        conf = self.get_config()
+        conf["run"]["bind"] += " %s:/dst" % (temp_dir1)
+        conf["run"]["bind"] += " %s:/dst" % (temp_dir2)
+        conf.write_conf()
+
+        s = self.assertPyrexContainerShellCommand("true", capture=True, returncode=1)
+        self.assertIn("Error: more than one bind for same destination path", s)
+
+    def test_conflicting_bind_options(self):
+        conf = self.get_config()
+        conf["run"]["bind"] += " /foo,optional"
+        conf["run"]["bind"] += " /foo"
+        conf.write_conf()
+
+        s = self.assertPyrexContainerShellCommand(
+            "test -e /foo", capture=True, returncode=1
+        )
+        self.assertIn("Error: more than one bind for same destination path", s)
+
     def test_bad_confversion(self):
         # Verify that a bad config is an error
         conf = self.get_config()

pyrex.py

@@ -369,6 +369,17 @@ def parse_bind_options(bind):
     return src, dst, options
 
 
+def prettyprint_bind(src, dst, options):
+    options_keys = list(vars(options).keys())
+    options_keys.sort()
+    options_str = ""
+    for k in options_keys:
+        if getattr(options, k):
+            options_str = options_str + ",{option}".format(option=k)
+
+    return "{src}:{dst}{options}".format(src=src, dst=dst, options=options_str)
+
+
 def prep_container(
     config,
     build_config,
@@ -547,13 +558,32 @@ def prep_container(
         + os.environ.get("PYREX_CONFIG_BIND", "").split()
         + extra_bind
     )
-    for b in set(binds):
+
+    binds_by_dst = {}
+    prettyprinted_binds_by_dst = {}
+
+    for b in binds:
         try:
             src, dst, options = parse_bind_options(b)
         except ParsingError as e:
             print("Error: %s" % e)
             return []
 
+        if dst in binds_by_dst:
+            # Allow identical entries
+            if prettyprint_bind(src, dst, options) == prettyprinted_binds_by_dst[dst]:
+                continue
+            else:
+                print(
+                    "Error: more than one bind for same destination path {dst}: '{bind1}' and '{bind2}'".format(
+                        dst=dst, bind1=binds_by_dst[dst], bind2=b
+                    )
+                )
+                return []
+        else:
+            binds_by_dst[dst] = b
+            prettyprinted_binds_by_dst[dst] = prettyprint_bind(src, dst, options)
+
         if not os.path.exists(src):
             if options.optional:
                 continue