core: Ensure TF_VERSION_STRING follows semantic versioning.

It currently does not (0.11.0rc2), however, with this unittest
future changes to the TF_VERSION_STRING should follow the
semantic versioning 2.0 spec described at www.semver.org
Change: 139404692

tensorflow/core/BUILD

@@ -1680,6 +1680,7 @@ tf_cc_tests(
         "util/reporter_test.cc",
         "util/saved_tensor_slice_util_test.cc",
         "util/sparse/sparse_tensor_test.cc",
+        "util/semver_test.cc",
         "util/tensor_slice_reader_test.cc",
         "util/tensor_slice_set_test.cc",
         "util/tensor_slice_util_test.cc",

tensorflow/core/util/semver_test.cc

@@ -0,0 +1,78 @@
+/* Copyright 2016 The TensorFlow Authors. All Rights Reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+==============================================================================*/
+
+#include "tensorflow/core/public/version.h"
+
+#include <string>
+#include "tensorflow/core/lib/core/stringpiece.h"
+#include "tensorflow/core/lib/strings/str_util.h"
+#include "tensorflow/core/platform/test.h"
+
+namespace tensorflow {
+namespace {
+
+bool IsDotOrIdentifierChar(char c) {
+  if (c == '.') return true;
+  if (c == '-') return true;
+  if (c >= 'A' && c <= 'Z') return true;
+  if (c >= 'a' && c <= 'z') return true;
+  if (c >= '0' && c <= '9') return true;
+  return false;
+}
+
+bool ConsumeDotSeparatedIdentifiers(StringPiece* s, const string& prefix,
+                                    StringPiece* val) {
+  if (!str_util::ConsumePrefix(s, prefix)) return false;
+  size_t i;
+  for (i = 0; i < s->size() && IsDotOrIdentifierChar((*s)[i]); ++i) {
+    // Intentionally empty
+  }
+  val->set(s->data(), i);
+  s->remove_prefix(i);
+  return i > 0;
+}
+
+// Test that TF_VERSION_STRING follows semantic versioning.
+TEST(SemverTest, VersionStringFollowsSemver) {
+  // Poor approximation of the semver 2.0 specification at www.semver.org.  Feel
+  // free to refine further (for example, check for leading 0s in numbers), but
+  // avoid adding dependencies.
+  uint64 major, minor, patch;
+  StringPiece prerelease, metadata;
+  StringPiece semver(TF_VERSION_STRING);
+
+  ASSERT_TRUE(str_util::ConsumeLeadingDigits(&semver, &major));
+  ASSERT_TRUE(str_util::ConsumePrefix(&semver, "."));
+  ASSERT_TRUE(str_util::ConsumeLeadingDigits(&semver, &minor));
+  ASSERT_TRUE(str_util::ConsumePrefix(&semver, "."));
+  // Till 0.11.0rc2, the prerelease version was (incorrectly) not separated from
+  // the patch version number. Let that slide.
+  // Remove this when TF_VERSION_STRING moves beyond 0.11.0rc2.
+  if (major == 0 && minor <= 11) {
+    return;
+  }
+  ASSERT_TRUE(str_util::ConsumeLeadingDigits(&semver, &patch));
+  if (semver.empty()) return;
+  if (semver[0] == '-') {
+    ASSERT_TRUE(ConsumeDotSeparatedIdentifiers(&semver, "-", &prerelease));
+  }
+  if (semver.empty()) return;
+  if (semver[0] == '+') {
+    ASSERT_TRUE(ConsumeDotSeparatedIdentifiers(&semver, "+", &metadata));
+  }
+  ASSERT_TRUE(semver.empty());
+}
+}  // namespace
+}  // namespace tensorflow