Fix run_before_script() output capturing

[tony]

tmuxp 1.52.0's before scripts print out a lot of newlines.

Summary by Sourcery

Bug Fixes:

• Fix issue where before scripts output was not being captured correctly.

[sourcery-ai]

Reviewer's Guide by Sourcery

This pull request modifies the run_before_script function to address excessive newlines in the output. It now captures stdout and stderr, and only prints to the terminal if it's a TTY. Additionally, it raises an exception if the script returns a non-zero exit code.

Sequence diagram for improved run_before_script execution flow

sequenceDiagram
    participant C as Caller
    participant R as run_before_script
    participant S as Shell Script
    participant T as Terminal

    C->>R: Execute script
    R->>S: Start process (Popen)
    activate S
    loop While script running
        S-->>R: Read stdout line
        alt is TTY
            R->>T: Write to stdout
        end
        S-->>R: Read stderr line
        alt is TTY
            R->>T: Write to stderr
        end
    end
    S-->>R: Return exit code
    deactivate S
    alt exit code != 0
        R->>R: Raise BeforeLoadScriptError
    end
    R-->>C: Return exit code

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Flow diagram for run_before_script error handling

flowchart TD
    A[Start] --> B{Script exists?}
    B -->|No| C[Raise BeforeLoadScriptNotExists]
    B -->|Yes| D[Start process]
    D --> E{Read output}
    E --> F{Is TTY?}
    F -->|Yes| G[Write to terminal]
    F -->|No| H[Buffer output]
    G --> I{Process finished?}
    H --> I
    I -->|No| E
    I -->|Yes| J{Exit code = 0?}
    J -->|Yes| K[Return exit code]
    J -->|No| L[Raise BeforeLoadScriptError]

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File-Level Changes

Change	Details	Files
Refactor the run_before_script function to capture and handle stdout and stderr streams.	The function now uses subprocess.Popen to execute the script. It captures stdout and stderr using pipes. It reads stdout and stderr line by line. It writes to the terminal only if it's a TTY. It stores the output in buffers. It raises an exception if the script returns a non-zero exit code, including the captured stderr. It handles FileNotFoundError exceptions.	src/tmuxp/util.py
Add a test case to verify that stdout is returned when the script succeeds.	The test case simulates sys.stdout.isatty() and sys.stderr.isatty() to ensure the output is written to the terminal.	tests/test_util.py

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[codecov]

Codecov Report

Attention: Patch coverage is 89.28571% with 3 lines in your changes missing coverage. Please review.

Project coverage is 73.11%. Comparing base (425bf3c) to head (03e6e68).
Report is 5 commits behind head on master.

Files with missing lines	Patch %	Lines
src/tmuxp/util.py	89.28%	2 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #959      +/-   ##
==========================================
+ Coverage   72.92%   73.11%   +0.18%     
==========================================
  Files          26       26              
  Lines        1843     1856      +13     
  Branches      350      352       +2     
==========================================
+ Hits         1344     1357      +13     
- Misses        394      395       +1     
+ Partials      105      104       -1     

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[sourcery-ai]

Hey @tony - I've reviewed your changes and they look great!

Here's what I looked at during the review

• 🟢 General issues: all looks good
• 🟢 Security: all looks good
• 🟡 Testing: 1 issue found
• 🟢 Complexity: all looks good
• 🟢 Documentation: all looks good

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