800ms in `loadCachesFrom` - better up-to-date check (for `Standard` libraries)

[JaroslavTulach]

• 800ms spend in loadCachesFrom
• ~half of that spend in computeDigestFromSource
• given all the sources are from standard libraries - e.g. premade by us
• we should be faster checking that they are not changed (as in 99.9% of cases they are not)

Originally posted by @JaroslavTulach in #13723 (comment)

[JaroslavTulach]

To builtin on prior knowledge: there is .lastModified API, let's paraphrase it a bit:

To speedup testing that module caches are up-to-date, the system recognizes special file inside of each library. If .bindings file is present in a library, then the content of the library is not scanned any more deeply and instead the time stamp of the file is used as last modification for the whole content of the library.

This API is primarily intended for use by installer, ensoup, distribution manager, that are supposed to create such file, as soon as they finish download/modifications to any library.

This file is ignored when accessing user projects, as it is expected that user can modify it, while the user usually does not have access permission or need to modify the shared installation libraries.

There already is .bindings file in each Standard library. If there is such a file, let's use it as a time check file without checking the state of any other files in the library. It is responsibility of those who modify the content of the library to update or remove the .bindings file.

Edit/Compile/Run

• buildEngineDistributionNoIndex has to remove any of such .bindings file (if it exists) in library that is modified.
• buildEngineDistribution updates (via enso --compile command) the .bindings file to be newer than any other file in the library.
• that way developers have fast edit/compile/run that ignores the .bindings cache file
• or they can wait for .bindings file to be properly recreated

[JaroslavTulach]

Related:

• Ability to --compile multiple projects at once #12937
• Consider using Foreign Memory API when reading .bindings #13816

[enso-bot]

Pavel Marek reports a new STANDUP for yesterday (2025-09-01):

Progress: - Examples.image tests are ignored - #13897

• Std lib bench dry-run takes too long - Ignore failing Multi_Value_Key stdlib benchmarks #13883 (comment)
  • Let's rather update the bench jobs to notify about failures. It should be finished by 2025-09-08.