fix pypa#352: add a envvar to ignore scm roots

CHANGELOG.rst

@@ -1,6 +1,7 @@
 v4.2.0
 ======
 
+* fix #352: add support for generally ignoring specific vcs roots
 * fix #471: better error for version bump failing on complex but accepted tag
 * fix #479: raise indicative error when tags carry non-parsable information
 * Add `no-guess-dev` which does no next version guessing, just adds `.post1.devN` in

README.rst

@@ -446,6 +446,11 @@ Environment variables
     derived, otherwise the current time is used
     (https://reproducible-builds.org/docs/source-date-epoch/)
 
+
+:SETUPTOOLS_SCM_IGNORE_VCS_ROOTS:
+    when defined, a ``os.pathsep`` separated list
+    of directory names to ignore for root finding
+
 Extending setuptools_scm
 ------------------------
 

src/setuptools_scm/file_finder.py

@@ -53,3 +53,12 @@ def _link_not_in_scm(n):
                 res.append(os.path.join(path, os.path.relpath(fullfilename, realpath)))
         seen.add(realdirpath)
     return res
+
+
+def is_toplevel_acceptable(toplevel):
+    if toplevel is None:
+        return False
+
+    return toplevel not in os.environ.get("SETUPTOOLS_SCM_IGNORE_VCS_ROOTS", "").split(
+        os.pathsep
+    )

src/setuptools_scm/file_finder_git.py

@@ -3,6 +3,7 @@
 import tarfile
 import logging
 from .file_finder import scm_find_files
+from .file_finder import is_toplevel_acceptable
 from .utils import trace
 
 log = logging.getLogger(__name__)
@@ -60,7 +61,7 @@ def _git_ls_files_and_dirs(toplevel):
 
 def git_find_files(path=""):
     toplevel = _git_toplevel(path)
-    if not toplevel:
+    if not is_toplevel_acceptable(toplevel):
         return []
     fullpath = os.path.abspath(os.path.normpath(path))
     if not fullpath.startswith(toplevel):

src/setuptools_scm/file_finder_hg.py

@@ -2,6 +2,7 @@
 import subprocess
 
 from .file_finder import scm_find_files
+from .file_finder import is_toplevel_acceptable
 
 
 def _hg_toplevel(path):
@@ -41,7 +42,7 @@ def _hg_ls_files_and_dirs(toplevel):
 
 def hg_find_files(path=""):
     toplevel = _hg_toplevel(path)
-    if not toplevel:
+    if not is_toplevel_acceptable(toplevel):
         return []
     hg_files, hg_dirs = _hg_ls_files_and_dirs(toplevel)
     return scm_find_files(path, hg_files, hg_dirs)

testing/test_file_finder.py

@@ -126,6 +126,12 @@ def test_symlink_file_out_of_git(inwd):
     assert set(find_files("adir")) == _sep({"adir/filea"})
 
 
+@pytest.mark.parametrize("path_add", ["{cwd}", "{cwd}:broken"])
+def test_ignore_root(inwd, monkeypatch, path_add):
+    monkeypatch.setenv("SETUPTOOLS_SCM_IGNORE_VCS_ROOTS", path_add.format(cwd=inwd.cwd))
+    assert find_files() == []
+
+
 def test_empty_root(inwd):
     subdir = inwd.cwd / "cdir" / "subdir"
     subdir.mkdir(parents=True)