dataconnect: shellcheck (lint) bash shell scripts

[dconeybe]

No description provided.

[dconeybe]

/gemini summary

[gemini-code-assist]

Summary of Changes

I've introduced shellcheck to our dataconnect bash scripts to improve their quality and maintainability. This PR adds a new shellcheck.sh script that lints all relevant bash files and applies various syntax improvements across existing scripts to adhere to shellcheck recommendations.

Highlights

• New Shellcheck Script: A new script, firebase-dataconnect/scripts/shellcheck.sh, has been added to automate the linting process for all bash scripts within the emulator and scripts directories.
• Bash Script Modernization: Several existing bash scripts have been updated to improve syntax and robustness, including changes to readonly variable declarations and consistent use of curly braces for variable expansions.
• Improved Path Handling: The method for defining SCRIPT_DIR and PROJECT_ROOT_DIR in multiple scripts has been modified, separating the assignment from the readonly declaration for better clarity and adherence to linting rules.
• Array Element Access Correction: Array element access in emulator.sh was corrected from "${gradle_emulator_binaries[@]}" to "${gradle_emulator_binaries[0]}" for more precise single-element retrieval.

Changelog

• firebase-dataconnect/emulator/emulator.sh
  • Changed the declaration of SCRIPT_DIR from a single-line readonly assignment to a two-line assignment followed by readonly.
  • Updated variable expansions from $arg to ${arg} and $emulator_binary to ${emulator_binary} for consistency.
  • Corrected array element access from "${gradle_emulator_binaries[@]}" to "${gradle_emulator_binaries[0]}" when expecting a single element.
  • Updated variable expansion from $wipe_and_restart_postgres_pod to ${wipe_and_restart_postgres_pod}.
• firebase-dataconnect/emulator/start_postgres_pod.sh
  • Changed the declaration of SCRIPT_DIR from a single-line readonly assignment using readlink -f to a two-line assignment followed by readonly.
• firebase-dataconnect/scripts/compile_kotlin.sh
  • Changed the declaration of PROJECT_ROOT_DIR from a single-line readonly assignment to a two-line assignment followed by readonly.
• firebase-dataconnect/scripts/emulator_run.sh
  • Changed the declaration of PROJECT_ROOT_DIR from a single-line readonly assignment to a two-line assignment followed by readonly.
• firebase-dataconnect/scripts/generateApiTxtFile.sh
  • Changed the declaration of PROJECT_ROOT_DIR from a single-line readonly assignment to a two-line assignment followed by readonly.
• firebase-dataconnect/scripts/generate_data_connect_sources.sh
  • Changed the declaration of PROJECT_ROOT_DIR from a single-line readonly assignment to a two-line assignment followed by readonly.
• firebase-dataconnect/scripts/run_all_tests.sh
  • Changed the declaration of PROJECT_ROOT_DIR from a single-line readonly assignment to a two-line assignment followed by readonly.
• firebase-dataconnect/scripts/run_integration_tests.sh
  • Changed the declaration of PROJECT_ROOT_DIR from a single-line readonly assignment to a two-line assignment followed by readonly.
• firebase-dataconnect/scripts/run_unit_tests.sh
  • Changed the declaration of PROJECT_ROOT_DIR from a single-line readonly assignment to a two-line assignment followed by readonly.
• firebase-dataconnect/scripts/shellcheck.sh
  • Added a new script to run shellcheck on all bash scripts within the emulator and scripts directories.
• firebase-dataconnect/scripts/spotlessApply.sh
  • Changed the declaration of PROJECT_ROOT_DIR from a single-line readonly assignment to a two-line assignment followed by readonly.

Activity

• github-actions[bot] posted a Javadoc Changes comment.
• google-oss-bot posted a Size Report.
• google-oss-bot posted a Coverage Report.
• google-oss-bot posted a Startup Time Report.
• gemini-code-assist[bot] suggested a more robust way to determine SCRIPT_DIR in firebase-dataconnect/emulator/emulator.sh.
• gemini-code-assist[bot] raised a concern about glob patterns in firebase-dataconnect/scripts/shellcheck.sh, suggesting shopt -s nullglob for robustness.
• dconeybe responded to the glob pattern concern, indicating that a failure in such cases is desired to highlight potentially incorrect patterns.
• gemini-code-assist[bot] suggested using printf for more robust command debugging output in firebase-dataconnect/scripts/shellcheck.sh.
• dconeybe requested a /gemini summary.