Consider invalid entries in the marker file reason for refetch

src/main/java/com/google/devtools/build/lib/rules/repository/RepoRecordedInput.java

@@ -26,6 +26,7 @@
 import com.google.devtools.build.lib.actions.FileValue;
 import com.google.devtools.build.lib.analysis.BlazeDirectories;
 import com.google.devtools.build.lib.cmdline.LabelConstants;
+import com.google.devtools.build.lib.cmdline.LabelSyntaxException;
 import com.google.devtools.build.lib.cmdline.LabelValidator;
 import com.google.devtools.build.lib.cmdline.RepositoryName;
 import com.google.devtools.build.lib.skyframe.ActionEnvironmentFunction;
@@ -76,25 +77,32 @@ public abstract static class Parser {
 
     /**
      * Parses a recorded input from the post-colon substring that identifies the specific input: for
-     * example, the {@code MY_ENV_VAR} part of {@code ENV:MY_ENV_VAR}.
+     * example, the {@code MY_ENV_VAR} part of {@code ENV:MY_ENV_VAR}. Returns null if the parsed
+     * part is invalid.
      */
     public abstract RepoRecordedInput parse(String s);
   }
 
   private static final Comparator<RepoRecordedInput> COMPARATOR =
-      Comparator.comparing((RepoRecordedInput rri) -> rri.getParser().getPrefix())
-          .thenComparing(RepoRecordedInput::toStringInternal);
+      (o1, o2) ->
+          o1 == o2
+              ? 0
+              : Comparator.comparing((RepoRecordedInput rri) -> rri.getParser().getPrefix())
+                  .thenComparing(RepoRecordedInput::toStringInternal)
+                  .compare(o1, o2);
 
   /**
    * Parses a recorded input from its string representation.
    *
    * @param s the string representation
-   * @return The parsed recorded input object, or {@code null} if the string representation is
-   *     invalid
+   * @return The parsed recorded input object, or {@link #NEVER_UP_TO_DATE} if the string
+   *     representation is invalid
    */
-  @Nullable
   public static RepoRecordedInput parse(String s) {
     List<String> parts = Splitter.on(':').limit(2).splitToList(s);
+    if (parts.size() < 2) {
+      return NEVER_UP_TO_DATE;
+    }
     for (Parser parser :
         new Parser[] {
           File.PARSER, Dirents.PARSER, DirTree.PARSER, EnvVar.PARSER, RecordedRepoMapping.PARSER
@@ -103,7 +111,7 @@ public static RepoRecordedInput parse(String s) {
         return parser.parse(parts.get(1));
       }
     }
-    return null;
+    return NEVER_UP_TO_DATE;
   }
 
   /**
@@ -172,6 +180,42 @@ public abstract boolean isUpToDate(
       Environment env, BlazeDirectories directories, @Nullable String oldValue)
       throws InterruptedException;
 
+  /** A sentinel "input" that's always out-of-date to signify parse failure. */
+  public static final RepoRecordedInput NEVER_UP_TO_DATE =
+      new RepoRecordedInput() {
+        @Override
+        public boolean equals(Object obj) {
+          return this == obj;
+        }
+
+        @Override
+        public int hashCode() {
+          return 12345678;
+        }
+
+        @Override
+        public String toStringInternal() {
+          throw new UnsupportedOperationException("this sentinel input should never be serialized");
+        }
+
+        @Override
+        public Parser getParser() {
+          throw new UnsupportedOperationException("this sentinel input should never be parsed");
+        }
+
+        @Override
+        public SkyKey getSkyKey(BlazeDirectories directories) {
+          // Return a random SkyKey to satisfy the contract.
+          return PrecomputedValue.STARLARK_SEMANTICS.getKey();
+        }
+
+        @Override
+        public boolean isUpToDate(
+            Environment env, BlazeDirectories directories, @Nullable String oldValue) {
+          return false;
+        }
+      };
+
   /**
    * Represents a filesystem path stored in a way that is repo-cache-friendly. That is, if the path
    * happens to point inside the current Bazel workspace (in either the main repo or an external
@@ -213,12 +257,12 @@ public final String toString() {
       return repoName().map(repoName -> repoName + "//" + path()).orElse(path().toString());
     }
 
-    public static RepoCacheFriendlyPath parse(String s) {
+    public static RepoCacheFriendlyPath parse(String s) throws LabelSyntaxException {
       if (LabelValidator.isAbsolute(s)) {
         int doubleSlash = s.indexOf("//");
         int skipAts = s.startsWith("@@") ? 2 : s.startsWith("@") ? 1 : 0;
         return createInsideWorkspace(
-            RepositoryName.createUnvalidated(s.substring(skipAts, doubleSlash)),
+            RepositoryName.create(s.substring(skipAts, doubleSlash)),
             PathFragment.create(s.substring(doubleSlash + 2)));
       }
       return createOutsideWorkspace(PathFragment.create(s));
@@ -264,7 +308,12 @@ public String getPrefix() {
 
           @Override
           public RepoRecordedInput parse(String s) {
-            return new File(RepoCacheFriendlyPath.parse(s));
+            try {
+              return new File(RepoCacheFriendlyPath.parse(s));
+            } catch (LabelSyntaxException e) {
+              // malformed inputs cause refetch
+              return NEVER_UP_TO_DATE;
+            }
           }
         };
 
@@ -356,7 +405,12 @@ public String getPrefix() {
 
           @Override
           public RepoRecordedInput parse(String s) {
-            return new Dirents(RepoCacheFriendlyPath.parse(s));
+            try {
+              return new Dirents(RepoCacheFriendlyPath.parse(s));
+            } catch (LabelSyntaxException e) {
+              // malformed inputs cause refetch
+              return NEVER_UP_TO_DATE;
+            }
           }
         };
 
@@ -439,7 +493,12 @@ public String getPrefix() {
 
           @Override
           public RepoRecordedInput parse(String s) {
-            return new DirTree(RepoCacheFriendlyPath.parse(s));
+            try {
+              return new DirTree(RepoCacheFriendlyPath.parse(s));
+            } catch (LabelSyntaxException e) {
+              // malformed inputs cause refetch
+              return NEVER_UP_TO_DATE;
+            }
           }
         };
 
@@ -576,8 +635,12 @@ public String getPrefix() {
           @Override
           public RepoRecordedInput parse(String s) {
             List<String> parts = Splitter.on(',').limit(2).splitToList(s);
-            return new RecordedRepoMapping(
-                RepositoryName.createUnvalidated(parts.get(0)), parts.get(1));
+            try {
+              return new RecordedRepoMapping(RepositoryName.create(parts.get(0)), parts.get(1));
+            } catch (LabelSyntaxException | IndexOutOfBoundsException e) {
+              // malformed inputs cause refetch
+              return NEVER_UP_TO_DATE;
+            }
           }
         };
 
@@ -632,9 +695,14 @@ public boolean isUpToDate(
         throws InterruptedException {
       RepositoryMappingValue repoMappingValue =
           (RepositoryMappingValue) env.getValue(getSkyKey(directories));
-      return repoMappingValue != RepositoryMappingValue.NOT_FOUND_VALUE
-          && RepositoryName.createUnvalidated(oldValue)
-              .equals(repoMappingValue.getRepositoryMapping().get(apparentName));
+      try {
+        return repoMappingValue != RepositoryMappingValue.NOT_FOUND_VALUE
+            && RepositoryName.create(oldValue)
+                .equals(repoMappingValue.getRepositoryMapping().get(apparentName));
+      } catch (LabelSyntaxException e) {
+        // malformed old value causes refetch
+        return false;
+      }
     }
   }
 }

src/main/java/com/google/devtools/build/lib/rules/repository/RepositoryDelegatorFunction.java

@@ -703,19 +703,25 @@ private static String readMarkerFile(
 
       boolean firstLine = true;
       for (String line : lines) {
+        if (line.isEmpty()) {
+          continue;
+        }
         if (firstLine) {
           markerRuleKey = line;
           firstLine = false;
         } else {
           int sChar = line.indexOf(' ');
           if (sChar > 0) {
             RepoRecordedInput input = RepoRecordedInput.parse(unescape(line.substring(0, sChar)));
-            if (input == null) {
-              // ignore invalid entries.
+            if (!input.equals(RepoRecordedInput.NEVER_UP_TO_DATE)) {
+              recordedInputValues.put(input, unescape(line.substring(sChar + 1)));
               continue;
             }
-            recordedInputValues.put(input, unescape(line.substring(sChar + 1)));
           }
+          // On parse failure, just forget everything else and mark the whole input out of date.
+          recordedInputValues.clear();
+          recordedInputValues.put(RepoRecordedInput.NEVER_UP_TO_DATE, "");
+          break;
         }
       }
       return markerRuleKey;

src/test/shell/bazel/starlark_repository_test.sh

@@ -2864,6 +2864,46 @@ EOF
   expect_log "I see: something"
 }
 
+function test_bad_marker_file_ignored() {
+  # when reading a file in another repo, we should watch it.
+  local outside_dir="${TEST_TMPDIR}/outside_dir"
+  mkdir -p "${outside_dir}"
+  echo nothing > ${outside_dir}/data.txt
+
+  create_new_workspace
+  cat > $(setup_module_dot_bazel) <<EOF
+foo = use_repo_rule("//:r.bzl", "foo")
+foo(name = "foo")
+bar = use_repo_rule("//:r.bzl", "bar")
+bar(name = "bar", data = "nothing")
+EOF
+  touch BUILD
+  cat > r.bzl <<EOF
+def _foo(rctx):
+  rctx.file("BUILD", "filegroup(name='foo')")
+  # intentionally grab a file that's not directly addressable by a label
+  otherfile = rctx.path(Label("@bar//subpkg:BUILD")).dirname.dirname.get_child("data.txt")
+  print("I see: " + rctx.read(otherfile))
+foo=repository_rule(_foo)
+def _bar(rctx):
+  rctx.file("subpkg/BUILD")
+  rctx.file("data.txt", rctx.attr.data)
+bar=repository_rule(_bar, attrs={"data":attr.string()})
+EOF
+
+  bazel build @foo >& $TEST_log || fail "expected bazel to succeed"
+  expect_log "I see: nothing"
+
+  local marker_file=$(bazel info output_base)/external/@+_repo_rules+foo.marker
+  # the marker file for this repo should contain a reference to "@@+_repo_rules+bar". Mangle that.
+  sed -i'' -e 's/@@+_repo_rules+bar/@@LOL@@LOL/g' ${marker_file}
+
+  # Running Bazel again shouldn't crash, and should result in a refetch.
+  bazel shutdown
+  bazel build @foo >& $TEST_log || fail "expected bazel to succeed"
+  expect_log "I see: nothing"
+}
+
 function test_file_watching_in_undefined_repo() {
   create_new_workspace
   cat > $(setup_module_dot_bazel) <<EOF