preserve set=True format

[smichr]

References to other Issues or PRs

Brief description of what is fixed or changed

make sure to keep set=True format even when there is no solution and always include the symbols

select this format with internal use where the tuple solution is needed

Other comments

Release Notes

• solvers
  • solve will always return a tuple (sym, sol) when set=True, even if sol is empty

[sympy-bot]

✅

Hi, I am the SymPy bot (v167). I'm here to help you write a release notes entry. Please read the guide on how to write release notes.

Your release notes are in good order.

Here is what the release notes will look like:

• solvers
  • solve will always return a tuple (sym, sol) when set=True, even if sol is empty (#23840 by @smichr)

This will be added to https://github.com/sympy/sympy/wiki/Release-Notes-for-1.12.

Click here to see the pull request description that was parsed.

<!-- Your title above should be a short description of what
was changed. Do not include the issue number in the title. -->

#### References to other Issues or PRs
<!-- If this pull request fixes an issue, write "Fixes #NNNN" in that exact
format, e.g. "Fixes #1234" (see
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#### Brief description of what is fixed or changed

make sure to keep set=True format even when there is no solution and always include the symbols

select this format with internal use where the tuple solution is needed

#### Other comments


#### Release Notes

<!-- Write the release notes for this release below between the BEGIN and END
statements. The basic format is a bulleted list with the name of the subpackage
and the release note for this PR. For example:

* solvers
  * Added a new solver for logarithmic equations.

* functions
  * Fixed a bug with log of integers.

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<!-- BEGIN RELEASE NOTES -->
* solvers
  * `solve` will always return a tuple `(sym, sol)` when `set=True`, even if `sol` is empty

<!-- END RELEASE NOTES -->

Update

The release notes on the wiki have been updated.

[github-actions]

Benchmark results from GitHub Actions

Lower numbers are good, higher numbers are bad. A ratio less than 1
means a speed up and greater than 1 means a slowdown. Green lines
beginning with + are slowdowns (the PR is slower then master or
master is slower than the previous release). Red lines beginning
with - are speedups.

Significantly changed benchmark results (PR vs master)

Significantly changed benchmark results (master vs previous release)

Full benchmark results can be found as artifacts in GitHub Actions
(click on checks at the top of the PR).

[oscarbenjamin]

Looks good to me.