${reportFileName.capitalized()} is taking too long to write.

Error message

${reportFileName.capitalized()} is taking too long to write... The build might finish before the report has been completely written.

What it means

The configuration-cache / problems HTML report is written asynchronously on a ManagedExecutor. On shutdown the writer waits up to 1 second (awaitTermination); if report tasks have not finished, shutdownNow() cancels the remainder, this warning is logged, and the unfinished task count goes to debug logs. The consequence is a possibly truncated or incomplete report file — the build itself is unaffected.

Source

Thrown at platforms/core-configuration/configuration-problems-base/src/main/kotlin/org/gradle/internal/configuration/problems/CommonReport.kt:200

                        writer.close()
                    }
                    executor.shutdown()
                }
                return Closed
            }

            private
            fun closeHtmlReport(details: JsonSource) {
                writer.endHtmlReport(details)
                writer.close()
            }

            private
            fun ManagedExecutor.shutdownAndAwaitTermination() {
                shutdown()
                if (!awaitTermination(1, TimeUnit.SECONDS)) {
                    val unfinishedTasks = shutdownNow()
                    logger.warn(
                        "${reportFileName.capitalized()} is taking too long to write... "
                            + "The build might finish before the report has been completely written."
                    )
                    logger.info("Unfinished tasks: {}", unfinishedTasks)
                }
            }

            private
            fun moveSpoolFileTo(outputDirectory: File): File {
                val reportDir = getReportDirectory(outputDirectory)

                val reportFile = reportDir.resolve("$reportFileName.html")
                if (distinctReports) {
                    if (!reportFile.exists()) {
                        moveFileToOutput(reportDir, reportFile)
                    }
                } else {
                    moveFileToOutput(reportDir, reportFile)

View on GitHub (pinned to 534f27719b)

Solutions

Re-run the build — usually transient under I/O contention
Write reports to fast local storage instead of network mounts
Reduce report volume by fixing reported problems or relaxing org.gradle.warning.mode
Check debug logs ('Unfinished tasks: N') to see how many tasks were dropped

Defensive patterns

Strategy: fallback

Validate before calling

# after the build, check the report landed intact before archiving
test -s build/reports/configuration-cache/report.html \
  || echo "configuration cache report incomplete — rerun before archiving"

Prevention

Keep build and report directories on local fast disks
Trim warning volume in very large builds
Do not treat the HTML report as guaranteed available before process exit

When it happens

Trigger: Very large builds producing thousands of configuration-cache/problems entries, slow or contended disks (network filesystems, throttled CI containers), or CPU overload making the 1-second grace period expire before spooled report tasks drain.

Common situations: Huge multi-project builds on CI; report directories on NFS or mounted volumes; builds with extensive problem diagnostics right after enabling stricter warning modes.

Related errors

AI-assisted analysis of gradle/gradle@534f27719b (2026-08-22). Data as JSON: /api/errors/3131d927e5fc404c. Report an issue: GitHub.