mcp-server-semgrep/semgrep-rules/python/lang/correctness/tempfile/flush.yaml

MCP Server for Semgrep Integration - static code analysis with AI

rules:
  - id: tempfile-without-flush
    languages:
      - python
    message:
      Using '$F.name' without '.flush()' or '.close()' may cause an error because the file may not exist when '$F.name'
      is used. Use '.flush()' or close the file before using '$F.name'.
    pattern-either:
      - patterns:
          - pattern-not-inside: |
              $F = tempfile.NamedTemporaryFile(...)
              ...
              $F.write(...)
              ...
              $F.flush()
              ...
              $F.name
          - pattern-not-inside: |
              $F = tempfile.NamedTemporaryFile(...)
              ...
              $F.write(...)
              ...
              $F.close()
              ...
              $F.name
          - pattern-not-inside: |
              $F = tempfile.NamedTemporaryFile(..., delete=False, ...)
              ...
              $F.close()
              ...
              $F.name
          - pattern-inside: |
              $F = tempfile.NamedTemporaryFile(...)
              ...
          - pattern: |
              $F.name
      - patterns:
          - pattern-not-inside: |
              with tempfile.NamedTemporaryFile(...) as $F:
                  ...
                  $F.write(...)
                  ...
                  $F.flush()
                  ...
                  $F.name
          - pattern-not-inside: |
              with tempfile.NamedTemporaryFile(...) as $F:
                  ...
                  $F.write(...)
                  ...
                  $F.close()
                  ...
                  $F.name
          - pattern-not-inside: |
              with tempfile.NamedTemporaryFile(...) as $F:
                  ...
                  $MODULE.dump(..., $F, ...)
                  ...
                  $F.flush()
                  ...
                  $F.name
          - pattern-not-inside: |
              with tempfile.NamedTemporaryFile(...) as $F:
                  ...
                  $MODULE.dump(..., $F, ...)
                  ...
                  $F.close()
                  ...
                  $F.name
          - pattern-inside: |
              with tempfile.NamedTemporaryFile(...) as $F:
                  ...
          - pattern: |
              $F.name
    severity: ERROR
    metadata:
      category: correctness
      technology:
        - python