rich 15.0.0: Preserve trailing newlines in Text.from_ansi and respect end delimiter in empty Console.print without silent character truncation or extra newline emission

# Rich Version Boundary Silent Behavioral Changes

## CSX Search Result
`search_known_solution` answered `NO_SAFE_MATCH` for Rich version boundary traps (returning unrelated results for `packaging.specifiers.SpecifierSet` sample `sha256:2158f71f8f0182e574ebf8c6a651b8c00cc0e084fe82523db391f8d026016a3c` and Dart shelf sample `sha256:2651162215727e626baac2f69d7b7e043707968fea0f9218aa9dda0648549e95`).

## What a Model Would Have Written Instead
A model assumes `Text.from_ansi(payload).plain` retains all trailing newline delimiters identically to the original payload string, and that calling `console.print(end="")` without positional arguments emits zero bytes to the stream just like Python's standard `print(end="")`.

## How the Wrong Version Fails
In Rich < 15.0.0 (e.g. 14.3.4), `Text.from_ansi("output\n").plain` silently drops trailing newlines (evaluating to `"output"` or `""` for `"\n"`), and `console.print(end="")` silently writes a hardcoded `\n` to the stream; in Rich < 14.0.0, setting `NO_COLOR=""` silently strips all terminal color formatting.

{"case":{"caseId":"case:sha256:a86e99264baee4e0c137112f39f17fd696387ad058d80a10bcafd4f0339c5273","contract":["assert Text.from_ansi('hello\\n').plain == 'hello\\n' preserving trailing newlines","assert Text.from_ansi('\\n').plain == '\\n' without stripping bare newline","assert Text.from_ansi('\\x1b[32mSUCCESS\\x1b[0m\\n').plain == 'SUCCESS\\n' with styled span","assert Console.print(end='') with empty objects outputs '' instead of hardcoded '\\n'","assert Console.print(end='\\r') outputs '\\r'","assert empty NO_COLOR='' env var does not disable console colors"],"goal":"Preserve trailing newlines in Text.from_ansi and respect end delimiter in empty Console.print without silent character truncation or extra newline emission","kind":"HOW","packages":["pkg:pypi/rich@15.0.0"],"schemaVersion":1,"symbols":["rich.text.Text.from_ansi","rich.console.Console.print"]},"contractCommand":["python","test/contract.py"],"environment":{"arch":"x64","ecosystem":"pypi","executionContext":"python","language":"python","os":"linux","packageManager":"pip","runtime":"python","schemaVersion":1},"license":"MIT-0","packages":["pkg:pypi/rich@15.0.0"],"schemaVersion":1,"symbols":["rich.text.Text.from_ansi","rich.console.Console.print"],"verifierAdapter":"python@1"}

rich==15.0.0

"""Rich ANSI and console formatting module."""

"""Helper routines illustrating Rich ANSI parsing and console stream output."""

from io import StringIO
from typing import Tuple
from rich.console import Console
from rich.text import Text


def parse_ansi_payload(payload: str) -> Tuple[str, int]:
    """Parse ANSI formatted text into plain string and span count.

    Preserves exact trailing and internal newlines in Rich >= 15.0.0.
    """
    text = Text.from_ansi(payload)
    return text.plain, len(text.spans)


def emit_empty_separator(buffer: StringIO, end: str = "") -> str:
    """Emit an empty print call with custom end delimiter to a string buffer.

    Respects the end parameter without emitting hardcoded newlines in Rich >= 15.0.0.
    """
    console = Console(file=buffer, force_terminal=False, color_system=None)
    console.print(end=end)
    return buffer.getvalue()

import io
import os
import sys

# Ensure project root is in sys.path
sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))

from rich.console import Console
from rich.text import Text
from src.ansi_formatter import emit_empty_separator, parse_ansi_payload

# -----------------------------------------------------------------------------
# 1. Text.from_ansi Trailing Newline Preservation Trap (Rich 15.0.0+)
# Naive model expectation: Text.from_ansi converts ANSI escape codes to styled
# spans and leaves plain text verbatim (including single and multiple newlines).
# Prior versions reality (Rich < 15.0.0): Text.from_ansi silently stripped trailing
# newlines (e.g., 'hello\n' -> 'hello', '\n' -> '').
# -----------------------------------------------------------------------------
plain, span_count = parse_ansi_payload("hello\n")
assert plain == "hello\n", f"Expected 'hello\\n', got {plain!r}"

plain_single_nl, _ = parse_ansi_payload("\n")
assert plain_single_nl == "\n", f"Expected '\\n', got {plain_single_nl!r}"

plain_multi_nl, _ = parse_ansi_payload("line1\nline2\n\n")
assert plain_multi_nl == "line1\nline2\n\n", f"Expected 'line1\\nline2\\n\\n', got {plain_multi_nl!r}"

plain_styled, styled_spans = parse_ansi_payload("\x1b[32mSUCCESS\x1b[0m\n")
assert plain_styled == "SUCCESS\n", f"Expected 'SUCCESS\\n', got {plain_styled!r}"
assert styled_spans == 1

# -----------------------------------------------------------------------------
# 2. Console.print Empty Object with Custom 'end' Delimiter Trap (Rich 15.0.0+)
# Naive model expectation: console.print(end="") with no positional arguments
# behaves identically to built-in Python print(end=""), emitting zero characters.
# Prior versions reality (Rich < 15.0.0): console.print(end="") completely ignored
# the 'end' parameter when positional objects were empty and hardcoded a '\n' write.
# -----------------------------------------------------------------------------
buf = io.StringIO()
result = emit_empty_separator(buf, end="")
assert result == "", f"Expected empty output from console.print(end=''), got {result!r}"

buf_cr = io.StringIO()
result_cr = emit_empty_separator(buf_cr, end="\r")
assert result_cr == "\r", f"Expected '\\r' from console.print(end='\\r'), got {result_cr!r}"

# -----------------------------------------------------------------------------
# 3. Environment Variable NO_COLOR='' & FORCE_COLOR='' Empty String Semantics
# Naive model expectation: NO_COLOR="" (empty string) means NO_COLOR is not set
# or disabled, per the no-color.org specification.
# Prior versions reality (Rich < 14.0.0): Rich checked `"NO_COLOR" in os.environ`,
# treating an empty string as active, silently disabling all terminal color output.
# -----------------------------------------------------------------------------
os.environ["NO_COLOR"] = ""
con_no_col = Console(force_terminal=True)
assert con_no_col.no_color is False, "Empty NO_COLOR should not disable color in Rich >= 14"

os.environ["FORCE_COLOR"] = ""
if "NO_COLOR" in os.environ:
    del os.environ["NO_COLOR"]
con_force_col = Console(force_terminal=False)
assert con_force_col.color_system is None, "Empty FORCE_COLOR should not force color system"

print("CONTRACT PASS: rich 15.0.0 newline preservation, empty print end delimiter, and NO_COLOR semantics verified")