RFR: 8264449: Enable reproducible builds with SOURCE_DATE_EPOCH [v13]

[John Neffenger]

On Fri, 7 Apr 2023 06:22:05 GMT, John Neffenger <jgneff at openjdk.org> wrote:

>> This pull request allows for reproducible builds of JavaFX on Linux, macOS, and Windows by defining the `SOURCE_DATE_EPOCH` environment variable. For example, the following commands create a reproducible build:
>> 
>> 
>> $ export SOURCE_DATE_EPOCH=$(git log -1 --pretty=%ct)
>> $ bash gradlew sdk jmods javadoc
>> $ strip-nondeterminism -v -T $SOURCE_DATE_EPOCH build/jmods/*.jmod
>> 
>> 
>> The three commands:
>> 
>> 1. set the build timestamp to the date of the latest source code change,
>> 2. build the JavaFX SDK libraries, JMOD archives, and API documentation, and
>> 3. recreate the JMOD files with stable file modification times and ordering.
>> 
>> The third command won't be necessary once Gradle can build the JMOD archives or the `jmod` tool itself has the required support. For more information on the environment variable, see the [`SOURCE_DATE_EPOCH`][1] page. For more information on the command to recreate the JMOD files, see the [`strip-nondeterminism`][2] repository. I'd like to propose that we allow for reproducible builds in JavaFX 17 and consider making them the default in JavaFX 18.
>> 
>> #### Fixes
>> 
>> There are at least four sources of non-determinism in the JavaFX builds:
>> 
>> 1. Build timestamp
>> 
>>     The class `com.sun.javafx.runtime.VersionInfo` in the JavaFX Base module stores the time of the build. Furthermore, for builds that don't run on the Hudson continuous integration tool, the class adds the build time to the system property `javafx.runtime.version`.
>> 
>> 2. Modification times
>> 
>>     The JAR, JMOD, and ZIP archives store the modification time of each file.
>> 
>> 3. File ordering
>> 
>>     The JAR, JMOD, and ZIP archives store their files in the order returned by the file system. The native shared libraries also store their object files in the order returned by the file system. Most file systems, though, do not guarantee the order of a directory's file listing.
>> 
>> 4. Build path
>> 
>>     The class `com.sun.javafx.css.parser.Css2Bin` in the JavaFX Graphics module stores the absolute path of its `.css` input file in the corresponding `.bss` output file, which is then included in the JavaFX Controls module.
>> 
>> This pull request modifies the Gradle and Groovy build files to fix the first three sources of non-determinism. A later pull request can modify the Java files to fix the fourth.
>> 
>> [1]: https://reproducible-builds.org/docs/source-date-epoch/
>> [2]: https://salsa.debian.org/reproducible-builds/strip-nondeterminism
>
> John Neffenger has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Revert format of timestamp in version OPT field

I reverted the version timestamp to the original format. The version looks like this for "release" early-access builds:


$ cat build5/sdk/lib/javafx.properties
javafx.version=21-ea
javafx.runtime.version=21-ea+12
javafx.runtime.build=12


and like this for developer builds:


$ cat build1/sdk/lib/javafx.properties
javafx.version=21-internal
javafx.runtime.version=21-internal+0-2023-04-06-232926
javafx.runtime.build=0


The only difference is that the timestamp is localized to UTC, while before it was in the local time of the build machine.

The `jmod --date` option requires the ISO 8601 extended format, so we need at least two different formats for the timestamp. Meanwhile, Java has no built-in support for parsing an ISO 8601 string in basic format, so both the current non-standard format and the standard basic format need a `DateTimeFormatter` with a custom pattern. There's no advantage from a parsing perspective in using the standard format:


    // Parses the format in the current JavaFX release
    var currentFormatter = DateTimeFormatter.ofPattern("yyyy-MM-dd-HHmmss");
    var localTime = LocalDateTime.parse(timestamp, currentFormatter);

    // Parses the ISO 8601 basic format
    var basicFormatter = DateTimeFormatter.ofPattern("yyyyMMdd'T'HHmmssX");
    var zonedTime = ZonedDateTime.parse(timestamp, basicFormatter);

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

PR Comment: https://git.openjdk.org/jfx/pull/446#issuecomment-1499982010