====

[[sec:scala_incremental_compilation]]
== Incremental compilation

By compiling only classes whose source code has changed since the previous compilation, and classes affected by these changes, incremental compilation can significantly reduce Scala compilation time. It is particularly effective when frequently compiling small code increments, as is often done at development time.

        }

        if (annotationProcessingConfigured) {

        return incremental;
    }

    /**
     * Used to enable or disable incremental compilation after a failure.
     * <p>
     * By default, incremental compilation after a failure is enabled for Java and Groovy.
     * It has no effect for Scala. It has no effect if incremental compilation is not enabled.
     * <p>

gFunctionalSpec/test/oww7k/settings.gradle into local compilation cache > Compiling settings file '/Users/daniel/gradle/gradle/build/tmp/teŝt files/BasicGroupedTaskLoggingFunctionalSpec/test/oww7k/settings.gradle' to cross build script cache\u001B[m\u001B[335D\u001B[1B\u001B[1A\u001B[1m> settings > Compiling /Users/daniel/gradle/gradle/build/tmp/teŝt files/BasicGroupedTaskLoggingFunctionalSpec/test/oww7k/settings.gradle into local compilation cache\u001B[m\u001B[0K\u001B[165D\u001B[1B\u001B[1A\u001B[1m>...

* The class analysis is also an output stored in the build cache, which means that if a compilation output is fetched from the build cache, then the incremental compilation analysis will be too and the next compilation will be incremental.

[[sec:incremental_compilation_known_issues]]
=== Known issues

        )
    }

    @Test
    fun `given a buildscript block compilation error, it reports correct error location`() {

        assertCorrectLocationIsReportedForErrorIn("buildscript")
    }

    @Test
    fun `given a plugins block compilation error, it reports correct error location`() {

        assertCorrectLocationIsReportedForErrorIn("plugins")
    }

                    ${snippets.body}
                }
            }

            def sneakyTask = tasks.register("sneakyTask", SneakyTask) {}

            // Ensure that buildSrc compilation triggers an exec task.
            tasks.named("classes").configure {
                dependsOn(sneakyTask)
            }
        """

        when:
        configurationCacheRun(":help")

// TPU devices to be used for execution (e.g. devices for TPUExecute ops) and
// their associated host CPU devices (for outside compilation). They are ordered
// by `num_replicas` followed by `num_cores_per_replica`.
using TPUDevicesAndHosts =
    llvm::SmallVector<llvm::SmallVector<TPUDeviceAndHost, 8>, 8>;

// TPU compilation device, execution and associated host devices, and optionally

 * the source files and where they're located
 * the compilation classpath, including any required dependencies (via Gradle <<dependency_management_terminology.adoc#sub:terminology_configuration,configurations>>)
 * where the compiled class files are placed

You can see how these relate to one another in this diagram:

.Source sets and Java compilation
image::java-sourcesets-compilation.png[]

        };
    }

    /**
     * The previous compilation analysis. Internal use only.
     *
     * @since 7.1
     */
    @OutputFile
    protected File getPreviousCompilationData() {
        if (previousCompilationDataFile == null) {
            previousCompilationDataFile = new File(getTemporaryDirWithoutCreating(), "previous-compilation-data.bin");
        }
        return previousCompilationDataFile;