@@ -69,6 +69,6 @@ public final class PreconditionsConstantMessage extends BugChecker implements Bu
         }
 
         return buildDescription(tree).setMessage(
-                "Preconditions.checkX() statement uses a non-constant message").build();
+                "Preconditions.checkX() statement uses a non-constant message. Consider using a template string").build();
     }
 }
/*
 * (c) Copyright 2017 Palantir Technologies Inc. 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.
 */

package com.palantir.baseline.errorprone;

import com.google.auto.service.AutoService;
import com.google.errorprone.BugPattern;
import com.google.errorprone.BugPattern.Category;
import com.google.errorprone.BugPattern.SeverityLevel;
import com.google.errorprone.VisitorState;
import com.google.errorprone.bugpatterns.BugChecker;
import com.google.errorprone.matchers.CompileTimeConstantExpressionMatcher;
import com.google.errorprone.matchers.Description;
import com.google.errorprone.matchers.Matcher;
import com.google.errorprone.matchers.Matchers;
import com.google.errorprone.matchers.method.MethodMatchers;
import com.sun.source.tree.ExpressionTree;
import com.sun.source.tree.MethodInvocationTree;
import java.util.List;
import java.util.regex.Pattern;

@AutoService(BugChecker.class)
@BugPattern(
        name = "PreconditionsConstantMessage",
        category = Category.GUAVA,
        severity = SeverityLevel.ERROR,
        summary = "Allow only constant messages to Preconditions.checkX() methods")
public final class PreconditionsConstantMessage extends BugChecker implements BugChecker.MethodInvocationTreeMatcher {

    private static final long serialVersionUID = 1L;

    private static final Matcher<ExpressionTree> PRECONDITIONS_METHOD =
            Matchers.anyOf(
                    MethodMatchers.staticMethod()
                            .onClass("com.google.common.base.Preconditions")
                            .withNameMatching(Pattern.compile("checkArgument|checkState|checkNotNull")));

    private final Matcher<ExpressionTree> compileTimeConstExpressionMatcher =
            new CompileTimeConstantExpressionMatcher();

    @Override
    public Description matchMethodInvocation(MethodInvocationTree tree, VisitorState state) {
        if (!PRECONDITIONS_METHOD.matches(tree, state)) {
            return Description.NO_MATCH;
        }

        List<? extends ExpressionTree> args = tree.getArguments();
        if (args.size() <= 1) {
            return Description.NO_MATCH;
        }

        ExpressionTree messageArg = args.get(1);

        if (compileTimeConstExpressionMatcher.matches(messageArg, state)) {
            return Description.NO_MATCH;
        }

        return buildDescription(tree).setMessage(
                "Preconditions.checkX() statement uses a non-constant message").build();
    }
}

`Consider using a template string with '%s'.`