feat: improve debugging

Make available partial results from ShellCheck

new outputs:

- `shellcheck-full`
- `shellcheck-head`
- `shellcheck-base`

README.md

@@ -401,6 +401,18 @@ Relative path to the HTML file containing detected defects. Example of how to us
   <img src="docs/images/html-output-exmple.png" width="800" alt="HTML output example" />
 </p>
 
+### `shellcheck-full`
+
+ShellCheck JSON output when Full scan is requested. Useful when debugging.
+
+### `shellcheck-head`
+
+ShellCheck JSON output for HEAD commit. Useful when debugging.
+
+### `shellcheck-base`
+
+ShellCheck JSON output for BASE commit. Useful when debugging.
+
 ## Using with Private repositories
 
 Differential ShellCheck GitHub Action could be used in private repositories by any user. But code scanning-related features are available only for GitHub Enterprise users, as mentioned in [GitHub Documentation](https://docs.github.com/en/code-security/code-scanning/automatically-scanning-your-code-for-vulnerabilities-and-errors/about-code-scanning):

src/index.sh

@@ -66,13 +66,19 @@ echo
 
 if [[ ${FULL_SCAN} -eq 0 ]]; then
   execute_shellcheck "${all_scripts[@]}" > "${WORK_DIR}full-shellcheck.err"
+
+  echo "shellcheck-full=${WORK_DIR}full-shellcheck.err" >> "${GITHUB_OUTPUT}"
+  is_debug && cat "${WORK_DIR}full-shellcheck.err"
 fi
 
 exit_status=0
 
 if ! is_strict_check_on_push_demanded; then
   execute_shellcheck "${only_changed_scripts[@]}" > "${WORK_DIR}head-shellcheck.err"
 
+  echo "shellcheck-head=${WORK_DIR}head-shellcheck.err" >> "${GITHUB_OUTPUT}"
+  is_debug && cat "${WORK_DIR}head-shellcheck.err"
+
   # Save the current state of the working directory
   git stash push --quiet
   # Checkout the base branch/commit
@@ -81,6 +87,10 @@ if ! is_strict_check_on_push_demanded; then
   execute_shellcheck "${only_changed_scripts[@]}" > "${WORK_DIR}base-shellcheck.err"
 
   get_fixes "${WORK_DIR}base-shellcheck.err" "${WORK_DIR}head-shellcheck.err"
+
+  echo "shellcheck-base=${WORK_DIR}base-shellcheck.err" >> "${GITHUB_OUTPUT}"
+  is_debug && cat "${WORK_DIR}base-shellcheck.err"
+
   evaluate_and_print_fixes
 
   get_defects "${WORK_DIR}head-shellcheck.err" "${WORK_DIR}base-shellcheck.err"