fix(unit_test_v2): restore deleted new_code_coverage.go referenced by action.yaml

[dmzrio]

Summary

The backend/unit_test_v2/action.yaml references ${{ github.action_path }}/calc_new_code_coverage/new_code_coverage.go in its "Run coverage analysis" step, but this file was deleted in commit f9d55729 while the action YAML was not updated.

This causes all workflows using kitabisa/composite-actions/backend/unit_test_v2@v2 (or any v2 tag) to fail with:

stat .../calc_new_code_coverage/new_code_coverage.go: no such file or directory

Fix

Restored the file from the last known good commit (2ec3f1a) before it was deleted.

---

Summary by cubic

Restores the deleted coverage helper referenced by the unit test v2 composite action so CI workflows run successfully again. Unblocks any workflow using kitabisa/composite-actions/backend/unit_test_v2@v2.

• Bug Fixes
  • Restored backend/unit_test_v2/calc_new_code_coverage/new_code_coverage.go referenced by backend/unit_test_v2/action.yaml.
  • Fixes failures that errored with “no such file or directory” when running the “Run coverage analysis” step.

^{Written for commit a8e8c6b. Summary will update on new commits.}

[cubic-dev-ai]

2 issues found across 1 file

Confidence score: 2/5

• In backend/unit_test_v2/calc_new_code_coverage/new_code_coverage.go, the CLI arg-length guard is off by one (len(os.Args) < 3 before reading os.Args[3]), so running with exactly program + diff-file + coverage-file will panic at runtime and break the coverage calculation flow — fix the guard/indexing (or validate required args explicitly) before merging.
• In backend/unit_test_v2/calc_new_code_coverage/new_code_coverage.go, parseNewFiles/newFiles naming suggests only newly created files, but it actually collects all +++ b/ paths (including modified files), which can mislead future changes and reviews — rename the function/variable (or add a clarifying comment) to reduce maintenance risk.

Prompt for AI agents (unresolved issues)

Check if these issues are valid — if so, understand the root cause of each and fix them. If appropriate, use sub-agents to investigate and fix each issue separately.


<file name="backend/unit_test_v2/calc_new_code_coverage/new_code_coverage.go">

<violation number="1" location="backend/unit_test_v2/calc_new_code_coverage/new_code_coverage.go:21">
P0: Index out of bounds panic when `os.Args` has exactly 3 elements (program + diff-file + coverage-file). The guard `len(os.Args) < 3` allows execution to proceed with 3 args, but `os.Args[3]` accesses an index that doesn't exist. While the action.yaml always passes 3 positional arguments making CI work, any manual invocation with just diff-file and coverage-file (as shown in the Usage message) will panic.</violation>

<violation number="2" location="backend/unit_test_v2/calc_new_code_coverage/new_code_coverage.go:58">
P3: Function name `parseNewFiles` and variable name `newFiles` are misleading — the function captures ALL files from `+++ b/` lines in the diff (i.e., all added and modified files, not just new files). The `--- a/` deletion logic doesn't achieve new-file-only filtering because in standard unified diffs the `---` line precedes `+++`, so the deletion runs first (no-op) and the subsequent `+++` line adds the file anyway.</violation>
</file>

Architecture diagram

sequenceDiagram
    participant Workflow as GitHub Workflow
    participant ActionYAML as unit_test_v2/action.yaml
    participant CoverageGo as calc_new_code_coverage/new_code_coverage.go
    participant DiffFile as Diff File (from git)
    participant CoverageFile as Go Coverage Output
    participant GoTool as go tool cover

    Note over Workflow,GoTool: Unit Test v2 Composite Action Runtime Flow

    Workflow->>ActionYAML: Trigger "Run coverage analysis" step
    ActionYAML->>CoverageGo: Execute go run new_code_coverage.go <diff-file> <coverage-file> <path-scanned>

    CoverageGo->>DiffFile: Parse diff file for changed files
    DiffFile-->>CoverageGo: Returns map of changed file paths

    CoverageGo->>GoTool: Run "go tool cover -func <coverage-file>"
    GoTool-->>CoverageGo: Returns coverage data per function/file

    CoverageGo->>CoverageGo: Filter coverage by changed files and path-scanned
    CoverageGo->>CoverageGo: Calculate per-file coverage percentage

    loop For each changed file in coverage data
        alt Coverage >= 80%
            CoverageGo->>CoverageGo: Append to "Coverage accepted" output
        else Coverage < 80%
            CoverageGo->>CoverageGo: Append to "Coverage below threshold" output
        end
    end

    CoverageGo-->>ActionYAML: Print coverage results to stdout
    ActionYAML-->>Workflow: Return step output (stdout captured by workflow)

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<sub>Reply with feedback, questions, or to request a fix.

Fix all with cubic | Re-trigger cubic</sub>

[cubic-dev-ai]

P0: Index out of bounds panic when os.Args has exactly 3 elements (program + diff-file + coverage-file). The guard len(os.Args) < 3 allows execution to proceed with 3 args, but os.Args[3] accesses an index that doesn't exist. While the action.yaml always passes 3 positional arguments making CI work, any manual invocation with just diff-file and coverage-file (as shown in the Usage message) will panic.

Prompt for AI agents

Check if this issue is valid — if so, understand the root cause and fix it. At backend/unit_test_v2/calc_new_code_coverage/new_code_coverage.go, line 21:

<comment>Index out of bounds panic when `os.Args` has exactly 3 elements (program + diff-file + coverage-file). The guard `len(os.Args) < 3` allows execution to proceed with 3 args, but `os.Args[3]` accesses an index that doesn't exist. While the action.yaml always passes 3 positional arguments making CI work, any manual invocation with just diff-file and coverage-file (as shown in the Usage message) will panic.</comment>

<file context>
@@ -0,0 +1,114 @@
+
+	diffFile := os.Args[1]
+	coverageFile := os.Args[2]
+	pathScanned := os.Args[3]
+
+	// Parse the diff file to get changed files
</file context>

[cubic-dev-ai]

P3: Function name parseNewFiles and variable name newFiles are misleading — the function captures ALL files from +++ b/ lines in the diff (i.e., all added and modified files, not just new files). The --- a/ deletion logic doesn't achieve new-file-only filtering because in standard unified diffs the --- line precedes +++, so the deletion runs first (no-op) and the subsequent +++ line adds the file anyway.

Prompt for AI agents

Check if this issue is valid — if so, understand the root cause and fix it. At backend/unit_test_v2/calc_new_code_coverage/new_code_coverage.go, line 58:

<comment>Function name `parseNewFiles` and variable name `newFiles` are misleading — the function captures ALL files from `+++ b/` lines in the diff (i.e., all added and modified files, not just new files). The `--- a/` deletion logic doesn't achieve new-file-only filtering because in standard unified diffs the `---` line precedes `+++`, so the deletion runs first (no-op) and the subsequent `+++` line adds the file anyway.</comment>

<file context>
@@ -0,0 +1,114 @@
+	}
+}
+
+func parseNewFiles(filename string) (map[string]bool, error) {
+	file, err := os.Open(filename)
+	if err != nil {
</file context>