debug: more options for short_stack

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

@@ -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:

coverage/control.py

@@ -354,7 +354,7 @@ def _post_init(self) -> None:
 
         # "[run] _crash" will raise an exception if the value is close by in
         # the call stack, for testing error handling.
-        if self.config._crash and self.config._crash in short_stack(limit=4):
+        if self.config._crash and self.config._crash in short_stack():
             raise RuntimeError(f"Crashing because called by {self.config._crash}")
 
     def _write_startup_debug(self) -> None:

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(skip: int = 0, full: bool = False, frame_ids: bool = False) -> str:
     """Return a string summarizing the call stack.
 
     The string is multi-line, with one line per stack frame. Each line shows
@@ -193,12 +193,11 @@ def short_stack(limit: Optional[int] = None, skip: int = 0) -> str:
         import_local_file : /Users/ned/coverage/trunk/coverage/backward.py:159
         ...
 
-    `limit` is the number of frames to include, defaulting to all of them.
-
     `skip` is the number of frames to skip, so that debugging functions can
     call this and not be included in the result.
 
-    Initial frames deemed uninteresting are automatically skipped.
+    If `full` is true, then include all frames.  Otherwise, initial "boring"
+    frames (ones in site-packages and earlier) are omitted.
 
     """
     # Regexes in initial frames that we don't care about.
@@ -208,23 +207,31 @@ def short_stack(limit: Optional[int] = None, skip: int = 0) -> str:
         r"\bsite-packages\b",   # pytest etc getting to our tests.
     ]
 
-    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
-        )
-    return "\n".join(f"{fi.function:>30s} : {fi.filename}:{fi.lineno}" for fi in stack)
+    stack: Iterable[inspect.FrameInfo] = inspect.stack()[:skip:-1]
+    if not full:
+        for pat in BORING_PRELUDE:
+            stack = itertools.dropwhile(
+                (lambda fi, pat=pat: re.search(pat, fi.filename)),  # type: ignore[misc]
+                stack
+            )
+    lines = []
+    for frame_info in stack:
+        line = f"{frame_info.function:>30s} : "
+        if frame_ids:
+            line += f"{id(frame_info.frame):#x} "
+        line += frame_info.filename
+        line += f":{frame_info.lineno}"
+        lines.append(line)
+    return "\n".join(lines)
 
 
 def dump_stack_frames(
-    limit: Optional[int] = None,
     out: Optional[TWritable] = None,
     skip: int = 0
 ) -> None:
     """Print a summary of the stack to stdout, or someplace else."""
     fout = out or sys.stdout
-    fout.write(short_stack(limit=limit, skip=skip+1))
+    fout.write(short_stack(skip=skip+1))
     fout.write("\n")
 
 

coverage/parser.py

@@ -720,7 +720,7 @@ def add_arc(
         """Add an arc, including message fragments to use if it is missing."""
         if self.debug:                      # pragma: debugging
             print(f"\nAdding possible arc: ({start}, {end}): {smsg!r}, {emsg!r}")
-            print(short_stack(limit=10))
+            print(short_stack())
         self.arcs.add((start, end))
 
         if smsg is not None or emsg is not None:

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

tests/test_debug.py

@@ -299,19 +299,40 @@ def test_short_stack(self) -> None:
         assert "f_two" in stack[2]
         assert "f_three" in stack[3]
 
-    def test_short_stack_limit(self) -> None:
-        stack = f_one(limit=2).splitlines()
-        assert 2 == len(stack)
-        assert "f_two" in stack[0]
-        assert "f_three" in stack[1]
-
     def test_short_stack_skip(self) -> None:
         stack = f_one(skip=1).splitlines()
         assert 3 == len(stack)
         assert "test_short_stack" in stack[0]
         assert "f_one" in stack[1]
         assert "f_two" in stack[2]
 
+    def test_short_stack_full(self) -> None:
+        stack_text = f_one(full=True)
+        s = re.escape(os.sep)
+        if env.WINDOWS:
+            pylib = "[Ll]ib"
+        else:
+            py = "pypy" if env.PYPY else "python"
+            majv, minv = sys.version_info[:2]
+            pylib = f"lib{s}{py}{majv}.{minv}"
+        assert len(re_lines(fr"{s}{pylib}{s}site-packages{s}_pytest", stack_text)) > 3
+        assert len(re_lines(fr"{s}{pylib}{s}site-packages{s}pluggy", stack_text)) > 3
+        assert not re_lines(r" 0x[0-9a-fA-F]+", stack_text) # No frame ids
+        stack = stack_text.splitlines()
+        assert len(stack) > 25
+        assert "test_short_stack" in stack[-4]
+        assert "f_one" in stack[-3]
+        assert "f_two" in stack[-2]
+        assert "f_three" in stack[-1]
+
+    def test_short_stack_frame_ids(self) -> None:
+        stack = f_one(full=True, frame_ids=True).splitlines()
+        frame_ids = [re.search(r" 0x[0-9a-fA-F]+", line)[0] for line in stack]
+        # Every line has a frame id.
+        assert len(frame_ids) == len(stack)
+        # All the frame ids are different.
+        assert len(set(frame_ids)) == len(frame_ids)
+
 
 def test_relevant_environment_display() -> None:
     env_vars = {