feat: add json-to-csv conversion via jq

[vitali87]

Summary

• Add csv as a target format for u7 cv json <input> to csv [yield <output>]
• Uses jq to convert a JSON array of objects to CSV with headers derived from keys_unsorted
• Includes file existence check, empty yield guard, atomic write via tmpfile, dry-run support, and _u7_require jq
• Unsupported formats return "Unsupported conversion" with exit code 1
• Updates help text to reflect the new yaml|csv target options

Test plan

• cv json to csv works -- converts JSON array to CSV with correct data
• cv json to csv reports missing file -- errors on nonexistent input
• cv json rejects unsupported format -- returns error for unsupported target
• cv json to csv dry-run -- prints dry-run message without writing
• All 151 existing tests still pass

[vitali87]

@greptile

[vitali87]

/gemini review

[gemini-code-assist]

Code Review

This pull request adds JSON-to-CSV conversion support using jq, including input validation for file existence and output paths, and updated help documentation. It also introduces new tests for both the conversion feature and the sh log command. Feedback recommends handling empty JSON arrays in the conversion logic to prevent failures, adding a corresponding test case for this edge case, and moving the unrelated sh log tests to a separate pull request to maintain a focused commit history.

[gemini-code-assist]

The test coverage for the new feature is great. To make it even more robust, I recommend adding a test case for handling an empty JSON array ([]) as input. This is an important edge case that should be handled gracefully (e.g., by producing an empty output file).

Here's an example test you could add:

# Test: Convert empty JSON array to CSV
echo '[]' > test_cv_empty.json
if command -v jq &>/dev/null; then
    u7 cv json test_cv_empty.json to csv yield test_cv_empty.csv >/dev/null 2>&1
    if [[ -f "test_cv_empty.csv" && ! -s "test_cv_empty.csv" ]]; then
        echo -e "${GREEN}✓${NC} cv json to csv with empty array works"
        ((PASSED++))
    else
        echo -e "${RED}✗${NC} cv json to csv with empty array failed"
        ((FAILED++))
    fi
else
    echo -e "${GREEN}✓${NC} cv json to csv with empty array (skipped - jq not installed)"
    ((PASSED++))
fi

[greptile-apps]

Greptile Summary

This PR adds csv as a target format for u7 cv json, implementing JSON-array-to-CSV conversion via jq. The implementation is solid: it includes an empty-yield guard, a file-existence check before any tool invocation, atomic output via a same-directory tmpfile, dry-run support, and a _u7_require jq dependency check. The jq filter correctly captures headers from the first object's keys and emits both the header row and data rows through @csv. Four new tests cover the happy path, missing file, unsupported format, and dry-run scenarios with appropriate jq availability guards.

Remaining feedback (both P2):

• The single line at lib/convert.sh:202 combines the jq filter, redirect, mv, and cleanup fallback into one expression — splitting it would improve readability and allow a more descriptive error message when jq fails.
• The CSV "works" test asserts only that a data value (Alice) appears in the output; adding an assertion for the header row would guard against regressions where headers are omitted or misplaced.

Confidence Score: 5/5

PR is safe to merge; all remaining findings are minor P2 style and test-quality suggestions that do not affect correctness.

The core logic is correct: file-existence guard, atomic write, dry-run, and dependency check are all properly implemented. The jq filter correctly handles empty arrays and produces valid CSV with consistent key ordering. No P0 or P1 issues remain. Both open comments are non-blocking style improvements.

No files require special attention.

Important Files Changed

Filename	Overview
lib/convert.sh	Adds CSV target to the json conversion case: empty-yield guard, file-existence check, atomic write via same-directory tmpfile, dry-run support, and jq dependency check. The jq filter correctly derives headers from the first object's keys. One style concern: the filter + mv + cleanup are packed into a single hard-to-read line.
test.sh	Adds four tests for json-to-csv (basic conversion, missing file, unsupported format, dry-run) with jq availability guards. The basic conversion test only asserts a data value is present, not that the CSV header row is correct.

Sequence Diagram

sequenceDiagram
    participant U as User
    participant S as convert.sh
    participant JQ as jq
    participant FS as Filesystem

    U->>S: u7 cv json input.json to csv [yield out.csv]
    S->>S: validate "to" keyword
    S->>S: resolve output path (default: input.csv)
    alt yield with empty arg
        S-->>U: Usage error (return 1)
    end
    S->>FS: check -f input.json
    alt file not found
        S-->>U: "File not found" (return 1)
    end
    S->>S: _u7_require jq
    alt jq not installed
        S-->>U: dependency error (return 1)
    end
    alt dry-run mode
        S-->>U: echo [dry-run] command
    else normal run
        S->>FS: mktemp output.csv.XXXXXX → tmpfile
        S->>JQ: jq -r '...' < input.json > tmpfile
        alt jq fails
            S->>FS: rm -f tmpfile
            S-->>U: return 1
        else jq succeeds
            S->>FS: mv tmpfile out.csv (atomic)
            S-->>U: success (exit 0)
        end
    end

Loading

Prompt To Fix All With AI

This is a comment left during a code review.
Path: test.sh
Line: 999

Comment:
**Test only validates data presence, not CSV structure**

The assertion checks that `"Alice"` appears somewhere in the output, but it does not verify that the header row (`"name","age"`) is present and appears _before_ the data rows. A bug that swaps header and data order, or emits only data with no header, would still pass this test.

Consider adding an assertion for the header, e.g.:

```suggestion
        assert_contains "cv json to csv works" "Alice" "$result"
        assert_contains "cv json to csv has headers" "name" "$result"
```

Or checking that line 1 of the output contains the expected header string.

How can I resolve this? If you propose a fix, please make it concise.

---

This is a comment left during a code review.
Path: lib/convert.sh
Line: 202

Comment:
**Dense one-liner mixes filter logic, I/O, and error handling**

The single line combines a 100+ character `jq` filter, the redirect, the `mv`, and the cleanup fallback all in one expression. This makes it hard to read at a glance and even harder to debug when `jq` emits an error — the failure path (`|| { rm -f "$tmpfile"; return 1; }`) gives the caller no additional context beyond jq's raw stderr.

Consider splitting into two statements with an explicit error check:

```bash
            if ! jq -r 'if length == 0 then empty else (.[0] | keys_unsorted) as $keys | $keys, map([.[ $keys[] ]])[] | @csv end' < "$input" > "$tmpfile"; then
              rm -f "$tmpfile"
              echo "Error: jq failed to convert '$input' to CSV"
              return 1
            fi
            mv "$tmpfile" "$output"
```

This keeps the cleanup and error message clearly separated while also surfacing a human-readable message when jq fails.

How can I resolve this? If you propose a fix, please make it concise.

_{Reviews (2): Last reviewed commit: "fix: handle empty JSON arrays in cv json..." | Re-trigger Greptile}

[gemini-code-assist]

Code Review

This pull request introduces JSON-to-CSV conversion using jq, adds input validation for the conversion process, and includes new tests for both the conversion and the sh log command. Feedback points out a bug when handling empty JSON arrays, providing a fix and suggesting a new test case for this scenario. Additionally, it is recommended to move the unrelated sh log tests to a separate pull request to keep the changes focused.

[gemini-code-assist]

The jq command will fail if the input JSON is an empty array (e.g., []), as .[0] will evaluate to null, causing an error. This will prevent the script from producing a valid (empty) CSV file for a valid (empty) input. To make the conversion more robust, you should handle this edge case.

Suggested change

	jq -r '(.[0] | keys_unsorted) as $keys | $keys, map([.[ $keys[] ]])[] | @csv' < "$input" > "$tmpfile" && mv "$tmpfile" "$output" || { rm -f "$tmpfile"; return 1; }
	jq -r 'if length > 0 then (.[0] | keys_unsorted) as $keys | $keys, map([.[ $keys[] ]])[] | @csv else "" end' < "$input" > "$tmpfile" && mv "$tmpfile" "$output" || { rm -f "$tmpfile"; return 1; }

[gemini-code-assist]

This pull request introduces a significant number of tests for the sh log command. While tests are always welcome, these changes seem unrelated to the primary goal of this PR, which is adding JSON-to-CSV conversion. To maintain a clean and understandable project history, it's best practice to keep pull requests focused on a single, specific feature or bug fix. Please consider moving these sh log tests to a separate pull request.

[gemini-code-assist]

The test suite for cv json to csv is missing a case for handling an empty JSON array, like []. The current implementation fails on this input. Adding a test for this scenario would have caught the bug and will prevent future regressions.

You could add a test like this:

# Test: Convert empty JSON array to CSV
echo '[]' > test_empty.json
u7 cv json test_empty.json to csv yield test_empty.csv >/dev/null 2>&1
if [[ -f "test_empty.csv" ]]; then
    result=$(cat test_empty.csv)
    assert_equals "cv json to csv with empty array is empty" "" "$result"
else
    echo -e "${RED}✗${NC} cv json to csv with empty array (file not created)"
    ((FAILED++))
fi

[vitali87]

@greptile