From 76213d102c1eaa91e733b326d9d312b60103d88a Mon Sep 17 00:00:00 2001
From: Johannes Bornhold <johannes.bornhold@gmail.com>
Date: Sat, 1 Apr 2017 12:19:53 +0200
Subject: python: Move catch_conflicts.py into subdirectory (#23600)

Python does add the script's directory into "sys.path". For the case of
"catch_conflicts.py" this means "/nix/store" is added to "sys.path". This can
result in very long delays if the store contains a lot of entries.
---
 .../interpreters/python/catch_conflicts.py         | 30 ----------------------
 .../interpreters/python/catch_conflicts/README.md  | 13 ++++++++++
 .../python/catch_conflicts/catch_conflicts.py      | 30 ++++++++++++++++++++++
 .../interpreters/python/mk-python-derivation.nix   |  9 +++----
 4 files changed, 47 insertions(+), 35 deletions(-)
 delete mode 100644 pkgs/development/interpreters/python/catch_conflicts.py
 create mode 100644 pkgs/development/interpreters/python/catch_conflicts/README.md
 create mode 100644 pkgs/development/interpreters/python/catch_conflicts/catch_conflicts.py

(limited to 'pkgs/development/interpreters')

diff --git a/pkgs/development/interpreters/python/catch_conflicts.py b/pkgs/development/interpreters/python/catch_conflicts.py
deleted file mode 100644
index bb82900c65a9..000000000000
--- a/pkgs/development/interpreters/python/catch_conflicts.py
+++ /dev/null
@@ -1,30 +0,0 @@
-import pkg_resources
-import collections
-import sys
-
-do_abort = False
-packages = collections.defaultdict(list)
-
-for f in sys.path:
-    for req in pkg_resources.find_distributions(f):
-        if req not in packages[req.project_name]:
-            # some exceptions inside buildPythonPackage
-            if req.project_name in ['setuptools', 'pip', 'wheel']:
-                continue
-            packages[req.project_name].append(req)
-
-
-for name, duplicates in packages.items():
-    if len(duplicates) > 1:
-        do_abort = True
-        print("Found duplicated packages in closure for dependency '{}': ".format(name))
-        for dup in duplicates:
-            print("  " + repr(dup))
-
-if do_abort:
-    print("")
-    print(
-        'Package duplicates found in closure, see above. Usually this '
-        'happens if two packages depend on different version '
-        'of the same dependency.')
-    sys.exit(1)
diff --git a/pkgs/development/interpreters/python/catch_conflicts/README.md b/pkgs/development/interpreters/python/catch_conflicts/README.md
new file mode 100644
index 000000000000..d144b80e3385
--- /dev/null
+++ b/pkgs/development/interpreters/python/catch_conflicts/README.md
@@ -0,0 +1,13 @@
+
+
+catch_conflicts.py
+==================
+
+The file catch_conflicts.py is in a subdirectory because, if it isn't, the
+/nix/store/ directory is added to sys.path causing a delay when building.
+
+Pointers:
+
+- https://docs.python.org/3/library/sys.html#sys.path
+
+- https://github.com/NixOS/nixpkgs/pull/23600
diff --git a/pkgs/development/interpreters/python/catch_conflicts/catch_conflicts.py b/pkgs/development/interpreters/python/catch_conflicts/catch_conflicts.py
new file mode 100644
index 000000000000..bb82900c65a9
--- /dev/null
+++ b/pkgs/development/interpreters/python/catch_conflicts/catch_conflicts.py
@@ -0,0 +1,30 @@
+import pkg_resources
+import collections
+import sys
+
+do_abort = False
+packages = collections.defaultdict(list)
+
+for f in sys.path:
+    for req in pkg_resources.find_distributions(f):
+        if req not in packages[req.project_name]:
+            # some exceptions inside buildPythonPackage
+            if req.project_name in ['setuptools', 'pip', 'wheel']:
+                continue
+            packages[req.project_name].append(req)
+
+
+for name, duplicates in packages.items():
+    if len(duplicates) > 1:
+        do_abort = True
+        print("Found duplicated packages in closure for dependency '{}': ".format(name))
+        for dup in duplicates:
+            print("  " + repr(dup))
+
+if do_abort:
+    print("")
+    print(
+        'Package duplicates found in closure, see above. Usually this '
+        'happens if two packages depend on different version '
+        'of the same dependency.')
+    sys.exit(1)
diff --git a/pkgs/development/interpreters/python/mk-python-derivation.nix b/pkgs/development/interpreters/python/mk-python-derivation.nix
index f30bd175daac..5d710fcad882 100644
--- a/pkgs/development/interpreters/python/mk-python-derivation.nix
+++ b/pkgs/development/interpreters/python/mk-python-derivation.nix
@@ -79,9 +79,10 @@ python.stdenv.mkDerivation (builtins.removeAttrs attrs ["disabled"] // {
   postFixup = ''
     wrapPythonPrograms
   '' + lib.optionalString catchConflicts ''
-    # check if we have two packages with the same name in closure and fail
-    # this shouldn't happen, something went wrong with dependencies specs
-    ${python.interpreter} ${./catch_conflicts.py}
+    # Check if we have two packages with the same name in the closure and fail.
+    # If this happens, something went wrong with the dependencies specs.
+    # Intentionally kept in a subdirectory, see catch_conflicts/README.md.
+    ${python.interpreter} ${./catch_conflicts}/catch_conflicts.py
   '' + attrs.postFixup or '''';
 
   passthru = {
@@ -98,5 +99,3 @@ python.stdenv.mkDerivation (builtins.removeAttrs attrs ["disabled"] // {
     isBuildPythonPackage = python.meta.platforms;
   };
 })
-
-
-- 
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