[tmp] Prevent pip installing build requirements

src/zc/buildout/easy_install.py

@@ -450,7 +450,7 @@ class Installer(object):
 
         tmp = tempfile.mkdtemp(dir=dest)
         try:
-            paths = call_pip_install(spec, tmp)
+            paths = call_pip_install(spec, tmp, self)
 
             dists = []
             env = pkg_resources.Environment(paths)
@@ -482,7 +482,7 @@ class Installer(object):
 
             result = []
             for d in dists:
-                result.append(_move_to_eggs_dir_and_compile(d, dest))
+                result.append(_move_to_eggs_dir_and_compile(d, dest, self))
 
             return result
 
@@ -668,7 +668,7 @@ class Installer(object):
                     raise zc.buildout.UserError(
                         "Couldn't download distribution %s." % avail)
 
-                dists = [_move_to_eggs_dir_and_compile(dist, self._dest)]
+                dists = [_move_to_eggs_dir_and_compile(dist, self._dest, self)]
                 for _d in dists:
                     if _d not in ws:
                         ws.add(_d, replace=True)
@@ -1815,7 +1815,7 @@ class IncompatibleConstraintError(zc.buildout.UserError):
 IncompatibleVersionError = IncompatibleConstraintError # Backward compatibility
 
 
-def call_pip_install(spec, dest):
+def call_pip_install(spec, dest, options):
     """
     Call `pip install` from a subprocess to install a
     distribution specified by `spec` into `dest`.
@@ -1828,6 +1828,12 @@ def call_pip_install(spec, dest):
     else:
         args.append('-v')
 
+    # Try to prevent pip from installing build dependencies implicitly
+    # and without respecting pinned versions, on the fly
+    if not options._allow_picked_versions:
+        args.append('--no-index')
+        args.append('--no-build-isolation')
+
     args.append(spec)
 
     try:
@@ -2035,7 +2041,7 @@ def _get_matching_dist_in_location(dist, location):
     if dist_infos == [(dist.project_name.lower(), dist.parsed_version)]:
         return dists.pop()
 
-def _move_to_eggs_dir_and_compile(dist, dest):
+def _move_to_eggs_dir_and_compile(dist, dest, options):
     """Move distribution to the eggs destination directory.
 
     And compile the py files, if we have actually moved the dist.
@@ -2076,7 +2082,7 @@ def _move_to_eggs_dir_and_compile(dist, dest):
                 unpacker(dist.location, tmp_dest)
                 [tmp_loc] = glob.glob(os.path.join(tmp_dest, '*'))
             else:
-                [tmp_loc] = call_pip_install(dist.location, tmp_dest)
+                [tmp_loc] = call_pip_install(dist.location, tmp_dest, options)
                 installed_with_pip = True
 
         # We have installed the dist. Now try to rename/move it.