为何Android Gradle插件3.1.2不支持Configuration on demand？版本兼容咨询

Great question—this is a compatibility quirk that caught many multi-module project maintainers off guard when Gradle 4.6 rolled out. Let’s break down why this happens and the key details you need to know:

Core Reasons for the Incompatibility #

• Misalignment with Gradle 4.6’s CoD Overhaul
  Gradle 4.6 introduced significant under-the-hood changes to its configuration-on-demand (CoD) feature, including stricter project isolation rules and revised task graph construction logic. The Android Gradle Plugin (AGP) 3.1.2 was built before these changes, and its internal workflows—like variant resolution, dependency parsing, and resource merge initialization—weren’t adapted to work with the updated CoD mechanism. Enabling CoD in this setup would lead to unpredictable issues: missing variants, dependency resolution failures, or even full build crashes.

• Proactive Compatibility Checks
  To prevent users from hitting silent build failures, the AGP team added a validation step in 3.1.x versions that detects when CoD is enabled alongside Gradle 4.6+. If the combination is detected, the plugin automatically disables CoD and falls back to full project configuration. This check was implemented quietly at the time, which is why you might not have seen it called out explicitly in the 3.1.2 release notes.

• Documentation Gap at the Time
  The official docs for AGP 3.1.2 didn’t explicitly call out this CoD restriction because the compatibility issue was identified after the plugin’s initial release. The details were later added to migration guides for newer AGP versions, but they weren’t retroactively updated in the 3.1.x documentation.

Key Details to Note #

• If you tried forcing CoD via org.gradle.configureondemand=true in your gradle.properties, AGP 3.1.2 would log a warning (check your build output) notifying you that CoD is unsupported and being disabled automatically.
• AGP 3.0.x and earlier versions work fine with CoD on Gradle 4.5 and below—this restriction only kicks in when combining AGP 3.1.x with Gradle 4.6+.
• To restore CoD functionality in a multi-module project, you’ll need to upgrade to AGP 3.2.0 or later. The 3.2.0 release explicitly fixed the CoD compatibility with Gradle 4.6+, and subsequent AGP versions further refined CoD performance for Android projects.

内容的提问来源于stack exchange，提问作者alessandro candolini