fix(infracost_breakdown): Make hook compatible with bash 3.2 (macOS)

[MaxymVlasov]

pull-back from fork

Put an x into the box if that apply:

• This PR introduces breaking change.
• This PR fixes a bug.
• This PR adds new functionality.
• This PR enhances existing functionality.

Description of your changes

This fixes the error line 77: -1: substring expression < 0 and replaces mapfile with something compatible for bash 3.x

• Replace mapfile with while-read loop for bash 3.2 compatibility
• Fix substring expressions to avoid negative indices: (${check: -1} => ${check:$((${#check}-1)):1})
• Replace negative array indexing with explicit length calculation
• Maintain identical functionality while supporting macOS default bash version

How can we test changes

I only tested my own use case which is to get a failed check if .totalMonthlyCost crosses a threshold:

    hooks:
      - id: infracost_breakdown
        args:
          - --args=--path=./
          # Fail if cost is higher than USD 4
          - --hook-config='.totalMonthlyCost|tonumber < 4'
          - --hook-config='.currency == "USD"'

[coderabbitai]

📝 Walkthrough

Summary by CodeRabbit

• Bug Fixes
  • Improved compatibility and correctness in string and array handling for better support on older Bash versions.

Walkthrough

The script in hooks/infracost_breakdown.sh was updated to improve compatibility with older Bash versions by replacing negative index string and array operations with explicit length-based calculations. Additionally, the use of mapfile was replaced with a while read loop for reading arrays, ensuring broader shell compatibility.

Changes

File(s)	Change Summary
hooks/infracost_breakdown.sh	Replaced negative index string and array operations with length-based slicing; replaced mapfile with while read loop for array population to support older Bash versions.

Sequence Diagram(s)

No sequence diagram generated as the changes do not affect control flow or introduce new features.

✨ Finishing Touches

• 📝 Generate Docstrings

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

🪧 Tips

Chat

There are 3 ways to chat with CodeRabbit:

• Review comments: Directly reply to a review comment made by CodeRabbit. Example:
  • I pushed a fix in commit <commit_id>, please review it.
  • Explain this complex logic.
  • Open a follow-up GitHub issue for this discussion.
• Files and specific lines of code (under the "Files changed" tab): Tag @coderabbitai in a new review comment at the desired location with your query. Examples:
  • @coderabbitai explain this code block.
  • @coderabbitai modularize this function.
• PR comments: Tag @coderabbitai in a new PR comment to ask questions about the PR branch. For the best results, please provide a very specific query, as very limited context is provided in this mode. Examples:
  • @coderabbitai gather interesting stats about this repository and render them as a table. Additionally, render a pie chart showing the language distribution in the codebase.
  • @coderabbitai read src/utils.ts and explain its main purpose.
  • @coderabbitai read the files in the src/scheduler package and generate a class diagram using mermaid and a README in the markdown format.
  • @coderabbitai help me debug CodeRabbit configuration file.

Support

Need help? Create a ticket on our support page for assistance with any issues or questions.

Note: Be mindful of the bot's finite context window. It's strongly recommended to break down tasks such as reading entire modules into smaller chunks. For a focused discussion, use review comments to chat about specific files and their changes, instead of using the PR comments.

CodeRabbit Commands (Invoked using PR comments)

• @coderabbitai pause to pause the reviews on a PR.
• @coderabbitai resume to resume the paused reviews.
• @coderabbitai review to trigger an incremental review. This is useful when automatic reviews are disabled for the repository.
• @coderabbitai full review to do a full review from scratch and review all the files again.
• @coderabbitai summary to regenerate the summary of the PR.
• @coderabbitai generate docstrings to generate docstrings for this PR.
• @coderabbitai generate sequence diagram to generate a sequence diagram of the changes in this PR.
• @coderabbitai resolve resolve all the CodeRabbit review comments.
• @coderabbitai configuration to show the current CodeRabbit configuration for the repository.
• @coderabbitai help to get help.

Other keywords and placeholders

• Add @coderabbitai ignore anywhere in the PR description to prevent this PR from being reviewed.
• Add @coderabbitai summary to generate the high-level summary at a specific location in the PR description.
• Add @coderabbitai anywhere in the PR title to generate the title automatically.

Documentation and Community

• Visit our Documentation for detailed information on how to use CodeRabbit.
• Join our Discord Community to get help, request features, and share feedback.
• Follow us on X/Twitter for updates and announcements.

[coderabbitai]

Actionable comments posted: 1

🧹 Nitpick comments (3)

hooks/infracost_breakdown.sh (3)

73-73: Guard against empty strings before slicing last_char
Extracting last_char with $((${#check} - 1)) will compute a negative index if check is empty, causing an error in Bash 3.2. Add a guard to skip empty checks, for example:

if [ ${#check} -eq 0 ]; then
  continue
fi
last_char=${check:$((${#check} - 1)):1}

---

77-77: Use POSIX parameter expansion to strip surrounding quotes
Rather than an arithmetic substring, you can remove the first and last character with native expansion, which is simpler and fully compatible with Bash 3.2:

- check="${check:1:$((${#check} - 2))}"
+ check=${check#?}
+ check=${check%?}

---

81-85: Feed grep via here-string to avoid echo quirks
Using echo "$check" may misinterpret escapes or flags. You can simplify to:

- done < <(echo "$check" | grep -oE '[!<>=]{1,2}')
+ done < <(grep -oE '[!<>=]{1,2}' <<< "$check")

This is more robust and avoids spawning an extra echo process.

📜 Review details

Configuration used: .coderabbit.yaml
Review profile: CHILL
Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between 79085a6 and 8ba9efb.

📒 Files selected for processing (1)

• hooks/infracost_breakdown.sh (1 hunks)

[coderabbitai]

🛠️ Refactor suggestion

Ensure operations is non-empty before indexing
If no operators are found, ${#operations[@]} will be 0 and indexing -1 will error. Add a check right before line 90, for example:

if [ ${#operations[@]} -eq 0 ]; then
  common::colorify "yellow" "Warning: no comparison operator found in expression: $check"
  have_failed_checks=true
  continue
fi
operation=${operations[$((${#operations[@]} - 1))]}

🤖 Prompt for AI Agents

In hooks/infracost_breakdown.sh at line 90, the code indexes the last element of
the operations array without checking if the array is empty, which can cause an
error. Add a conditional check before line 90 to verify if the operations array
length is zero; if it is, log a warning message, set have_failed_checks to true,
and continue to the next iteration. Only assign operation from the last element
of operations if the array is non-empty.

[MaxymVlasov]

Double-checked on

    - id: infracost_breakdown
      args:
        # - --args=--config-file=test/infracost.yml
        # - --args=--path=./environment/qa
        # - --args=--terraform-plan-flags="-var-file=../../test.tfvars"
        # - --args=--terraform-plan-flags="-var-file=../../test2.tfvars"
        # - --hook-config='.totalHourlyCost >= 0.1'
        # - --hook-config=".totalHourlyCost|tonumber > 1"
        # - -h ".projects[].diff.totalMonthlyCost|tonumber!=10000"
        # - -h [.projects[].diff.totalMonthlyCost | select (.!=null) | tonumber] | add > 1000
      verbose: true # Always show costs

using 1 --hook-config at once - works fine

[antonbabenko]

This PR is included in version 1.99.2 🎉