[pub] Fix update fails when project contains dependency from Dart SDK

[chika3742]

What are you trying to accomplish?

I have noticed that under certain conditions, Dependabot fails to create updates with the following logs:

updater | 2024/11/15 12:51:41 INFO <job_917330574> Checking if custom_lint 0.6.8 needs updating
updater | 2024/11/15 12:51:41 INFO <job_917330574> Latest version is 0.7.0
updater | 2024/11/15 12:51:41 INFO <job_917330574> Requirements to unlock update_not_possible
updater | 2024/11/15 12:51:41 INFO <job_917330574> Requirements update strategy 
2024/11/15 12:51:41 INFO <job_917330574> No update possible for custom_lint 0.6.8

Upon investigation, I found that the following error occurred in dependency_services internal, interrupting the update resolution. (different dependency, but same cause.)

Because every version of flutter from sdk depends on collection 1.18.0 and analyzer >=6.8.0 depends on collection ^1.19.0, flutter from sdk is incompatible with
  analyzer >=6.8.0.
And because analyzer >=6.6.0 <6.9.0 depends on macros >=0.1.2-main.3 <0.1.3, if flutter from sdk and analyzer >=6.6.0 then macros >=0.1.2-main.3 <0.1.3.
And because macros >=0.1.2-main.2 <0.1.2-main.4 depends on _macros 0.3.1 from sdk and macros >=0.1.2-main.4 <0.1.3-main.0 depends on _macros 0.3.2 from sdk, if flutter
  from sdk and analyzer >=6.6.0 then _macros 0.3.1 or 0.3.2 from sdk.
And because _macros from sdk doesn't exist (could not find package _macros in the Dart SDK) and riverpod_lint >=2.6.1 <3.0.0-dev.0 depends on analyzer ^6.7.0, flutter
  from sdk is incompatible with riverpod_lint >=2.6.1 <3.0.0-dev.0.
So, because my_project depends on both flutter from sdk and riverpod_lint ^2.6.1, version solving failed.

(Excerpt)

_macros from sdk doesn't exist (could not find package _macros in the Dart SDK) 

Packages such as analyzer depend on macros package, which depends on _macros which is included in the Dart SDK. When the project depends on such packages, Dependabot will no longer create any PRs because dependency_services cannot find _macros package.

This PR passes the DART_ROOT environment variable to dependency_services so that it can find the Dart SDK.

Related Issue

• update_not_possible message #8903
  • I read the issue again but I can't determine if the cause is the same for now.

Anything you want to highlight for special attention from reviewers?

How will you know you've accomplished your goal?

pubspec.yaml

name: foo
environment:
  sdk: '^3.5.0'

dev_dependencies:
  riverpod_lint: 2.6.1

(riverpod_lint depends on analyzer)

Command Line

$ dependabot update pub _ --local .

Result

(before)

...
updater | 2024/11/17 12:14:27 INFO Finished job processing
  proxy | 2024/11/17 12:14:29 Skipping sending metrics because api endpoint is empty
  proxy | 2024/11/17 12:14:29 34/239 calls cached (14%)

(after)

...
updater | 2024/11/17 12:08:16 INFO Finished job processing
updater | 2024/11/17 12:08:16 INFO Results:
updater | +-------------------------------------------------+
updater | |       Changes to Dependabot Pull Requests       |
updater | +---------+---------------------------------------+
updater | | created | riverpod_lint ( from 2.6.1 to 2.6.2 ) |
updater | +---------+---------------------------------------+
  proxy | 2024/11/17 12:08:18 Skipping sending metrics because api endpoint is empty
  proxy | 2024/11/17 12:08:18 159/376 calls cached (42%)

Checklist

• I have run the complete test suite to ensure all tests and linters pass.
• I have thoroughly tested my code changes to ensure they work as expected, including adding additional tests for new functionality.
• I have written clear and descriptive commit messages.
• I have provided a detailed description of the changes in the pull request, including the problem it addresses, how it fixes the problem, and any relevant details about the implementation.
• I have ensured that the code is well-documented and easy to understand.

[abdulapopoola]

Thanks @chika3742 !

[sachin-sandhu]

approving, LGTM