1 files changed, 54 insertions, 13 deletions
diff --git a/pre_commit/languages/dotnet.py b/pre_commit/languages/dotnet.py
index 3983c6f..e26b45c 100644
--- a/pre_commit/languages/dotnet.py
+++ b/pre_commit/languages/dotnet.py
@@ -2,6 +2,10 @@ from __future__ import annotations
 
 import contextlib
 import os.path
+import re
+import tempfile
+import xml.etree.ElementTree
+import zipfile
 from typing import Generator
 from typing import Sequence
 
@@ -35,6 +39,22 @@ def in_env(prefix: Prefix) -> Generator[None, None, None]:
         yield
 
 
+@contextlib.contextmanager
+def _nuget_config_no_sources() -> Generator[str, None, None]:
+    with tempfile.TemporaryDirectory() as tmpdir:
+        nuget_config = os.path.join(tmpdir, 'nuget.config')
+        with open(nuget_config, 'w') as f:
+            f.write(
+                '<?xml version="1.0" encoding="utf-8"?>'
+                '<configuration>'
+                '  <packageSources>'
+                '    <clear />'
+                '  </packageSources>'
+                '</configuration>',
+            )
+        yield nuget_config
+
+
 def install_environment(
         prefix: Prefix,
         version: str,
@@ -57,21 +77,42 @@ def install_environment(
             ),
         )
 
-        # Determine tool from the packaged file <tool_name>.<version>.nupkg
-        build_outputs = os.listdir(os.path.join(prefix.prefix_dir, build_dir))
-        for output in build_outputs:
-            tool_name = output.split('.')[0]
+        nupkg_dir = prefix.path(build_dir)
+        nupkgs = [x for x in os.listdir(nupkg_dir) if x.endswith('.nupkg')]
+
+        if not nupkgs:
+            raise AssertionError('could not find any build outputs to install')
+
+        for nupkg in nupkgs:
+            with zipfile.ZipFile(os.path.join(nupkg_dir, nupkg)) as f:
+                nuspec, = (x for x in f.namelist() if x.endswith('.nuspec'))
+                with f.open(nuspec) as spec:
+                    tree = xml.etree.ElementTree.parse(spec)
+
+            namespace = re.match(r'{.*}', tree.getroot().tag)
+            if not namespace:
+                raise AssertionError('could not parse namespace from nuspec')
+
+            tool_id_element = tree.find(f'.//{namespace[0]}id')
+            if tool_id_element is None:
+                raise AssertionError('expected to find an "id" element')
+
+            tool_id = tool_id_element.text
+            if not tool_id:
+                raise AssertionError('"id" element missing tool name')
 
             # Install to bin dir
-            helpers.run_setup_cmd(
-                prefix,
-                (
-                    'dotnet', 'tool', 'install',
-                    '--tool-path', os.path.join(envdir, BIN_DIR),
-                    '--add-source', build_dir,
-                    tool_name,
-                ),
-            )
+            with _nuget_config_no_sources() as nuget_config:
+                helpers.run_setup_cmd(
+                    prefix,
+                    (
+                        'dotnet', 'tool', 'install',
+                        '--configfile', nuget_config,
+                        '--tool-path', os.path.join(envdir, BIN_DIR),
+                        '--add-source', build_dir,
+                        tool_id,
+                    ),
+                )
 
         # Clean the git dir, ignoring the environment dir
         clean_cmd = ('git', 'clean', '-ffxd', '-e', f'{ENVIRONMENT_DIR}-*')