Optimize VisitorState#getConstantExpression #4586
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I filed this PR as a result of work in PicnicSupermarket/error-prone-support#1138, where I found out that I overlooked VisitorState#getConstantExpression and instead reinvented the wheel.
| } else { | ||
| sb.append(c); | ||
| } | ||
| if (!(value instanceof CharSequence str)) { |
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I added a second commit that enables a further optimization by accepting any CharSequence; this can be backed out if desired.
| if (c == '\'') { | ||
| sb.append('\''); | ||
| } else { | ||
| sb.append(Convert.quote(c)); |
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Incidentally I recently learned that Convert.quote does the thing we'd want now, but only for JDK 23+: openjdk/jdk@144a08e
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Er, and as a result of that change Convert.quote(char) was replaced with Convert.quote(char, boolean), so this change doesn't work with the latest JDK EA builds.
I'm not sure what the best option is. We could use reflection or MR-JARs to call the method.
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Ah, nice catch! I haven't looked at the MR-JAR setup yet, but indeed reflection should work. TBD whether I'll find some time today for a new pass.
| } else { | ||
| sb.append(c); | ||
| } | ||
| if (!(value instanceof CharSequence str)) { |
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Unfortunately we're not quite ready to start using Java > 11 features in non-test code internally. I can remove the instanceof pattern when importing this, I'm just leaving a note here in case you wonder why it disappears.
By avoiding a second pass over the string.
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Rebased and added a commit with a multi-release JAR approach. Locally this makes the build pass with JDK 25.ea.3-open.
I suspect that changes to .github/workflows/ci.yml are required, but as the GitHub Actions workflow isn't auto-triggered, I'm not sure 👀.
I'll cross-reference this PR in #3756.
| <execution> | ||
| <id>java23</id> | ||
| <goals> | ||
| <goal>compile</goal> | ||
| </goals> | ||
| <configuration> | ||
| <jdkToolchain> | ||
| <version>23</version> | ||
| </jdkToolchain> | ||
| <compileSourceRoots> | ||
| <compileSourceRoot>${basedir}/src/main/java23</compileSourceRoot> | ||
| </compileSourceRoots> | ||
| <!-- multiReleaseOutput requires setting release --> | ||
| <outputDirectory>${project.build.outputDirectory}/META-INF/versions/23</outputDirectory> | ||
| </configuration> | ||
| </execution> |
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A few things are of note here:
- Without
<goal>compile</goal>this execution is skipped. This also means that thejava24execution below is currently a no-op. - This configuration doesn't override the inherited
<source>17</source>and<target>17</target>settings, though it could. (If so, we should do the same below.) - I'm not sure each of these executions should use an exactly-matching toolchain JDK version. Perhaps it's better to use the latest JDK whenever possible, so as to minimize the number of JDKs required.
| <plugin> | ||
| <groupId>org.apache.maven.plugins</groupId> | ||
| <artifactId>maven-jar-plugin</artifactId> | ||
| <configuration> | ||
| <archive> | ||
| <manifestEntries> | ||
| <Multi-Release>true</Multi-Release> | ||
| </manifestEntries> | ||
| </archive> | ||
| </configuration> | ||
| </plugin> |
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Also had to add this to make sure that the class file bundled under META-INF/versions/23 is picked up.
| /** | ||
| * @see VisitorState#getConstantExpression(Object) | ||
| */ | ||
| final class ConstantStringExpressions { | ||
| private ConstantStringExpressions() {} |
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Certainly open to approaches other than a special-purpose static utility class named com.google.errorprone.ConstantStringExpressions.
| } | ||
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| // Don't escape single-quotes in string literals. | ||
| CharSequence str = (CharSequence) value; |
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Dropped the instanceof pattern matching as suggested here.
| return state | ||
| .getElements() | ||
| .getConstantExpression( | ||
| value instanceof CharSequence charSequence ? charSequence.toString() : value); |
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Here I did keep the instanceof pattern matching, because this code anyway only applies to JDK 23+, but if that anyway impacts the Google-internal setup, that can be changed, of course.
By avoiding a second pass over the string.