RFR: 8258117: jar tool sets the time stamp of module-info.class entries to the current time [v2]

[Lance Andersen]

On Sep 23, 2021, at 2:28 AM, Jaikiran Pai <jpai at openjdk.java.net<mailto:jpai at openjdk.java.net>> wrote:

On Fri, 17 Sep 2021 12:54:07 GMT, Jaikiran Pai <jpai at openjdk.org<mailto:jpai at openjdk.org>> wrote:

The commit here is a potential fix for the issue noted in https://bugs.openjdk.java.net/browse/JDK-8258117.

The change here repurposes an existing internal interface `ModuleInfoEntry` to keep track of the last modified timestamp of a `module-info.class` descriptor.

This commit uses the timestamp of the `module-info.class` on the filesystem to set the time on the `JarEntry`. There are a couple of cases to consider here:

1. When creating a jar  (using `--create`), we use the source `module-info.class` from the filesystem and then add extended info to it (attributes like packages, module version etc...). In such cases, this patch will use the lastmodified timestamp from the filesystem of `module-info.class` even though we might end up updating/extending/modifying (for example by adding a module version) its content while storing it as a `JarEntry`.

2. When updating a jar (using `--update`), this patch will use the lastmodified timestamp of `module-info.class` either from the filesystem or from the source jar's entry (depending on whether a new `module-info.class` is being passed to the command). Here too, it's possible that we might end up changing/modifying/extending the `module-info.class` (for example, changing the module version to a new version) that gets written into the updated jar file, but this patch _won't_ use `System.currentTimeMillis()` even in such cases.

If we do have to track actual changes that might happen to `module-info.class` while extending its info (in `extendedInfoBytes()`) and then decide whether to use current system time as last modified time, then this will require a bigger change and also a discussion on what kind of extending of module-info.class content will require a change to the lastmodifiedtime of that entry.

Jaikiran Pai has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains two additional commits since the last revision:

- Merge latest from master branch
- 8258117: jar tool sets the time stamp of module-info.class entries to the current time

Any reviews for this one, please?

Hi Jaikiran

This is on my todo list, sorry for the delay.

Hoping we can get a couple additional eyes on this as well.

Best
Lance

-------------

PR: https://git.openjdk.java.net/jdk/pull/5486

[cid:E1C4E2F0-ECD0-4C9D-ADB4-B16CA7BCB7FC at home]



Lance Andersen| Principal Member of Technical Staff | +1.781.442.2037
Oracle Java Engineering
1 Network Drive
Burlington, MA 01803
Lance.Andersen at oracle.com<mailto:Lance.Andersen at oracle.com>



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