From c3463a7a2659288b7c35178750a61dae745d3182 Mon Sep 17 00:00:00 2001
From: Ned Batchelder <ned@nedbatchelder.com>
Date: Sun, 12 Nov 2023 07:23:20 -0500
Subject: [PATCH] debug: short_stack(full=False)

Now we have the option to show the full stack or an abbreviated stack.
But debug=premain should still show the complete stack.
---
 coverage/cmdline.py   |  2 +-
 coverage/debug.py     | 13 +++++++------
 tests/test_cmdline.py | 16 +++++++++++++---
 3 files changed, 21 insertions(+), 10 deletions(-)

diff --git a/coverage/cmdline.py b/coverage/cmdline.py
index 67243b230..d24242140 100644
--- a/coverage/cmdline.py
+++ b/coverage/cmdline.py
@@ -892,7 +892,7 @@ def do_debug(self, args: List[str]) -> int:
             write_formatted_info(print, "config", self.coverage.config.debug_info())
         elif args[0] == "premain":
             print(info_header("premain"))
-            print(short_stack())
+            print(short_stack(full=True))
         elif args[0] == "pybehave":
             write_formatted_info(print, "pybehave", env.debug_info())
         else:
diff --git a/coverage/debug.py b/coverage/debug.py
index ba1f0fde4..0e000eb52 100644
--- a/coverage/debug.py
+++ b/coverage/debug.py
@@ -181,7 +181,7 @@ def exc_one_line(exc: Exception) -> str:
     return "|".join(l.rstrip() for l in lines)
 
 
-def short_stack(limit: Optional[int] = None, skip: int = 0) -> str:
+def short_stack(limit: Optional[int] = None, skip: int = 0, full: bool = False) -> str:
     """Return a string summarizing the call stack.
 
     The string is multi-line, with one line per stack frame. Each line shows
@@ -209,11 +209,12 @@ def short_stack(limit: Optional[int] = None, skip: int = 0) -> str:
     ]
 
     stack: Iterable[inspect.FrameInfo] = inspect.stack()[limit:skip:-1]
-    for pat in BORING_PRELUDE:
-        stack = itertools.dropwhile(
-            (lambda fi, pat=pat: re.search(pat, fi.filename)),  # type: ignore[misc]
-            stack
-        )
+    if not full:
+        for pat in BORING_PRELUDE:
+            stack = itertools.dropwhile(
+                (lambda fi, pat=pat: re.search(pat, fi.filename)),  # type: ignore[misc]
+                stack
+            )
     return "\n".join(f"{fi.function:>30s} : {fi.filename}:{fi.lineno}" for fi in stack)
 
 
diff --git a/tests/test_cmdline.py b/tests/test_cmdline.py
index a310371f1..f5eb3d1e8 100644
--- a/tests/test_cmdline.py
+++ b/tests/test_cmdline.py
@@ -6,6 +6,7 @@
 from __future__ import annotations
 
 import ast
+import os
 import pprint
 import re
 import sys
@@ -333,16 +334,25 @@ def test_debug_pybehave(self) -> None:
     def test_debug_premain(self) -> None:
         self.command_line("debug premain")
         out = self.stdout()
+        # -- premain ---------------------------------------------------
         #   ... many lines ...
+        #           _multicall : /Users/ned/cov/trunk/.tox/py39/site-packages/pluggy/_callers.py:77
         #   pytest_pyfunc_call : /Users/ned/cov/trunk/.tox/py39/site-packages/_pytest/python.py:183
         #   test_debug_premain : /Users/ned/cov/trunk/tests/test_cmdline.py:284
         #         command_line : /Users/ned/cov/trunk/tests/coveragetest.py:309
         #         command_line : /Users/ned/cov/trunk/tests/coveragetest.py:472
         #         command_line : /Users/ned/cov/trunk/coverage/cmdline.py:592
         #             do_debug : /Users/ned/cov/trunk/coverage/cmdline.py:804
-        assert re.search(r"(?m)^\s+test_debug_premain : .*[/\\]tests[/\\]test_cmdline.py:\d+$", out)
-        assert re.search(r"(?m)^\s+command_line : .*[/\\]coverage[/\\]cmdline.py:\d+$", out)
-        assert re.search(r"(?m)^\s+do_debug : .*[/\\]coverage[/\\]cmdline.py:\d+$", out)
+        lines = out.splitlines()
+        s = re.escape(os.sep)
+        assert lines[0].startswith("-- premain ----")
+        assert len(lines) > 25
+        assert re.search(fr"{s}site-packages{s}_pytest{s}", out)
+        assert re.search(fr"{s}site-packages{s}pluggy{s}", out)
+        assert re.search(fr"(?m)^\s+test_debug_premain : .*{s}tests{s}test_cmdline.py:\d+$", out)
+        assert re.search(fr"(?m)^\s+command_line : .*{s}coverage{s}cmdline.py:\d+$", out)
+        assert re.search(fr"(?m)^\s+do_debug : .*{s}coverage{s}cmdline.py:\d+$", out)
+        assert "do_debug : " in lines[-1]
 
     def test_erase(self) -> None:
         # coverage erase