fix: Show correct default path in signer error messages

[swarna1101]

Problem

When Solana CLI configuration contains an invalid keypair_path, error messages suggest creating new keypairs at the misconfigured location instead of the user's actual default directory. This leads to confusion and keypairs being created in wrong locations (e.g., /home/sol/identity/id.json instead of $HOME/.config/solana/id.json).

Solution

Modified error message generation in DefaultSigner::path() to always suggest the system default path (~/.config/solana/id.json) based on the user's actual home directory, regardless of any misconfigured paths in config files.

@KirillLykov can you check this, closes #6637

[KirillLykov]

I double checked, it fixes the problem. Thanks a lot!

[mergify]

Backports to the beta branch are to be avoided unless absolutely necessary for fixing bugs, security issues, and perf regressions. Changes intended for backport should be structured such that a minimum effective diff can be committed separately from any refactoring, plumbing, cleanup, etc that are not strictly necessary to achieve the goal. Any of the latter should go only into master and ride the normal stabilization schedule. Exceptions include CI/metrics changes, CLI improvements and documentation updates on a case by case basis.

[mergify]

automerge label removed due to a CI failure

[codecov-commenter]

Codecov Report

❌ Patch coverage is 0% with 16 lines in your changes missing coverage. Please review.
✅ Project coverage is 83.0%. Comparing base (2933846) to head (94f0251).
⚠️ Report is 5 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #7849   +/-   ##
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  Coverage    83.0%    83.0%           
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  Files         809      809           
  Lines      356483   356497   +14     
=======================================
+ Hits       296203   296227   +24     
+ Misses      60280    60270   -10     

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[t-nelson]

i don't understand why
a) the original message was wrong, nor
b) the fix committed here is correct

creating a key at the code default path does not fix there not being a keypair file at the path specified in the config. all tools should respect the values in the config file. if the user has specified that they wish to use a keypair file at a path that does not, or no longer, contains one, the correctness of that decision is not for us to decide. it may well be exactly that they intend to use the path and that creating a key there is the correct advice

i think this change should be reverted

[KirillLykov]

Actually,

i don't understand why a) the original message was wrong, nor b) the fix committed here is correct

creating a key at the code default path does not fix there not being a keypair file at the path specified in the config. all tools should respect the values in the config file. if the user has specified that they wish to use a keypair file at a path that does not, or no longer, contains one, the correctness of that decision is not for us to decide. it may well be exactly that they intend to use the path and that creating a key there is the correct advice

i think this change should be reverted

You are right, that's my misunderstanding of where this path to /home/sol/ comes from. I completely forgot about this config.yaml file existence. Please approve: #7882