perf(engine): optimize Terraform parser with directory caching and LOC-based memory calculation

[cx-artur-ribeiro]

Reason for Proposed Changes

KICS experienced OOM errors when scanning large Terraform codebases due to:

• O(n²) complexity in variable resolution (rescanning all .tf files for every file parsed);
• Memory estimation based only on file count, ignoring actual file sizes;

Proposed Changes

• Added directory-level caching for Terraform variable resolution;
• Thread-safe cache reduces complexity from O(n²) to O(n);
• Eliminates redundant file scans (e.g., 247 terraform files: from 61,009 → 247 reads);
• Enhanced file statistics with LOC tracking;
• Provides per-platform statistics;
• Fixed secrets inspector to not fail scan when secrets queires timeout;

I submit this contribution under the Apache-2.0 license.

[gitguardian]

⚠️ GitGuardian has uncovered 1 secret following the scan of your pull request.

Please consider investigating the findings and remediating the incidents. Failure to do so may lead to compromising the associated services or software components.

🔎 Detected hardcoded secret in your pull request

GitGuardian id	GitGuardian status	Secret	Commit	Filename
21271469	Triggered	Generic Password	5fd3a69	assets/queries/terraform/azure/unrestricted_sql_server_access/test/negative5.tf	View secret

🛠 Guidelines to remediate hardcoded secrets

1. Understand the implications of revoking this secret by investigating where it is used in your code.
2. Replace and store your secret safely. Learn here the best practices.
3. Revoke and rotate this secret.
4. If possible, rewrite git history. Rewriting git history is not a trivial act. You might completely break other contributing developers' workflow and you risk accidentally deleting legitimate data.

To avoid such incidents in the future consider

• following these best practices for managing and storing secrets including API keys and other credentials
• install secret detection on pre-commit to catch secret before it leaves your machine and ease remediation.

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[github-actions]

KICS version: v2.1.13

Category Results CRITICAL 0 HIGH 0 MEDIUM 0 LOW 0 INFO 0 TRACE 0 TOTAL 0	Metric Values Files scanned 1 Files parsed 1 Files failed to scan 0 Total executed queries 47 Queries failed to execute 0 Execution time 0

[cx-eduardo-semanas]

LGTM

[cx-rui-araujo]

@cx-artur-ribeiro check my comment pls

[cx-rui-araujo]

If the cache key is the full path, it can sometimes become quite large. Should this be a hash instead?
Please ask the rest of the team for their opinions