Compat with chardet 7 (#3886)

.github/workflows/tests.yml

diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 891c15f..16bc8ba 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -32,6 +32,9 @@
           - "ubuntu-24.04-arm"
         include:
           - python-version: "3.10"
+            kind: "old"
+            os: "ubuntu-24.04-arm"
+          - python-version: "3.10"
             kind: "no-toml"
             os: "ubuntu-24.04-arm"
           - python-version: "3.13"
@@ -58,6 +61,8 @@
           pip install -e ".[dev]" # install the codespell dev packages
       - run: pip install aspell-python-py3
         if: startsWith(matrix.os, 'ubuntu')
+      - run: pip install "chardet<7"
+        if: ${{ matrix.kind == 'old' }}
       - run: codespell --help
       - run: codespell --version
       - run: make check

.gitignore

diff --git a/.gitignore b/.gitignore
index f4d749b..cb3acd2 100644
--- a/.gitignore
+++ b/.gitignore
@@ -14,3 +14,4 @@
 codespell_lib/_version.py
 junit-results.xml
 *.egg-info/
+.DS_Store

codespell_lib/_codespell.py

diff --git a/codespell_lib/_codespell.py b/codespell_lib/_codespell.py
index 82c2730..c5b5b4e 100644
--- a/codespell_lib/_codespell.py
+++ b/codespell_lib/_codespell.py
@@ -223,14 +223,18 @@
 
     def init_chardet(self) -> None:
         try:
-            from chardet.universaldetector import UniversalDetector
-        except ImportError as e:
+            import chardet  # noqa: F401
+        except ImportError:
             msg = (
                 "There's no chardet installed to import from. "
                 "Please, install it and check your PYTHONPATH "
                 "environment variable"
             )
-            raise ImportError(msg) from e
+            raise ImportError(msg)
+        try:
+            from chardet import UniversalDetector
+        except ImportError:  # chardet < 7
+            from chardet.universaldetector import UniversalDetector
 
         self.encdetector = UniversalDetector()