Make lockfile version parsing more robust

Instead of using a regex, get the lockfile version by parsing the lockfile as arbitrary JSON and then later fit it to the expected schema.
bazelbuild · Nov 11, 2023 · 6adbd18 · 6adbd18
1 parent 07a571f
commit 6adbd18
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Showing 2 changed files with 30 additions and 16 deletions.
diff --git a/src/main/java/com/google/devtools/build/lib/bazel/bzlmod/BazelLockFileFunction.java b/src/main/java/com/google/devtools/build/lib/bazel/bzlmod/BazelLockFileFunction.java
@@ -27,7 +27,6 @@
 import com.google.devtools.build.lib.profiler.SilentCloseable;
 import com.google.devtools.build.lib.server.FailureDetails.ExternalDeps.Code;
 import com.google.devtools.build.lib.skyframe.PrecomputedValue.Precomputed;
-import com.google.devtools.build.lib.vfs.FileSystemUtils;
 import com.google.devtools.build.lib.vfs.Path;
 import com.google.devtools.build.lib.vfs.Root;
 import com.google.devtools.build.lib.vfs.RootedPath;
@@ -36,20 +35,23 @@
 import com.google.devtools.build.skyframe.SkyFunctionException.Transience;
 import com.google.devtools.build.skyframe.SkyKey;
 import com.google.devtools.build.skyframe.SkyValue;
+import com.google.gson.Gson;
+import com.google.gson.JsonObject;
+import com.google.gson.JsonPrimitive;
 import com.google.gson.JsonSyntaxException;
+import java.io.BufferedReader;
 import java.io.FileNotFoundException;
 import java.io.IOException;
-import java.util.regex.Matcher;
-import java.util.regex.Pattern;
+import java.io.InputStreamReader;
+import java.util.Optional;
 import javax.annotation.Nullable;
 
 /** Reads the contents of the lock file into its value. */
 public class BazelLockFileFunction implements SkyFunction {
 
   public static final Precomputed<LockfileMode> LOCKFILE_MODE = new Precomputed<>("lockfile_mode");
 
-  private static final Pattern LOCKFILE_VERSION_PATTERN =
-      Pattern.compile("\"lockFileVersion\":\\s*(\\d+)");
+  private static final String LOCK_FILE_VERSION_KEY = "lockFileVersion";
 
   private final Path rootDirectory;
 
@@ -99,17 +101,29 @@ public SkyValue compute(SkyKey skyKey, Environment env)
   public static BazelLockFileValue getLockfileValue(RootedPath lockfilePath) throws IOException {
     BazelLockFileValue bazelLockFileValue;
     try {
-      String json = FileSystemUtils.readContent(lockfilePath.asPath(), UTF_8);
-      Matcher matcher = LOCKFILE_VERSION_PATTERN.matcher(json);
-      int version = matcher.find() ? Integer.parseInt(matcher.group(1)) : -1;
+      Gson gson =
+          GsonTypeAdapterUtil.createLockFileGson(
+              lockfilePath
+                  .asPath()
+                  .getParentDirectory()
+                  .getRelative(LabelConstants.MODULE_DOT_BAZEL_FILE_NAME));
+      JsonObject jsonObject;
+      try (var reader =
+          new BufferedReader(
+              new InputStreamReader(lockfilePath.asPath().getInputStream(), UTF_8))) {
+        jsonObject = gson.fromJson(reader, JsonObject.class);
+      }
+      int version;
+      try {
+        version =
+            Optional.ofNullable(jsonObject.get(LOCK_FILE_VERSION_KEY))
+                .orElse(new JsonPrimitive(-1))
+                .getAsInt();
+      } catch (NumberFormatException e) {
+        version = -1;
+      }
       if (version == BazelLockFileValue.LOCK_FILE_VERSION) {
-        bazelLockFileValue =
-            GsonTypeAdapterUtil.createLockFileGson(
-                    lockfilePath
-                        .asPath()
-                        .getParentDirectory()
-                        .getRelative(LabelConstants.MODULE_DOT_BAZEL_FILE_NAME))
-                .fromJson(json, BazelLockFileValue.class);
+        bazelLockFileValue = gson.fromJson(jsonObject, BazelLockFileValue.class);
       } else {
         // This is an old version, needs to be updated
         // Keep old version to recognize the problem in error mode

diff --git a/src/test/java/com/google/devtools/build/lib/bazel/bzlmod/BazelLockFileFunctionTest.java b/src/test/java/com/google/devtools/build/lib/bazel/bzlmod/BazelLockFileFunctionTest.java
@@ -535,7 +535,7 @@ public void invalidLockfileMalformed() throws Exception {
             Pattern.quote(
                     "Failed to read and parse the MODULE.bazel.lock file with error:"
                         + " java.lang.IllegalStateException: Expected BEGIN_ARRAY but was STRING at"
-                        + " line 1 column 129 path $.flags.allowedYankedVersions")
+                        + " path $.flags.allowedYankedVersions")
                 + ".*"
                 + Pattern.quote("Try deleting it and rerun the build."),
             Pattern.DOTALL);