search for double backslashes in prefix replacement

conda_build/build.py

@@ -97,9 +97,13 @@ def have_prefix_files(files):
     '''
     prefix = config.build_prefix
     prefix_bytes = prefix.encode('utf-8')
-    alt_prefix = prefix.replace('\\', '/')
-    alt_prefix_bytes = alt_prefix.encode('utf-8')
     prefix_placeholder_bytes = prefix_placeholder.encode('utf-8')
+    if on_win:
+        forward_slash_prefix = prefix.replace('\\', '/')
+        forward_slash_prefix_bytes = forward_slash_prefix.encode('utf-8')
+        double_backslash_prefix = prefix.replace('\\', '\\\\')
+        double_backslash_prefix_bytes = double_backslash_prefix.encode('utf-8')
+
     for f in files:
         if f.endswith(('.pyc', '.pyo', '.a')):
             continue
@@ -130,9 +134,12 @@ def have_prefix_files(files):
                 mm = mmap.mmap(fi.fileno(), 0)
         if mm.find(prefix_bytes) != -1:
             yield (prefix, mode, f)
-        if (sys.platform == 'win32') and mm.find(alt_prefix_bytes) != -1:
+        if on_win and mm.find(forward_slash_prefix_bytes) != -1:
             # some windows libraries use unix-style path separators
-            yield (alt_prefix, mode, f)
+            yield (forward_slash_prefix, mode, f)
+        elif on_win and mm.find(double_backslash_prefix_bytes) != -1:
+            # some windows libraries have double backslashes as escaping
+            yield (double_backslash_prefix, mode, f)
         if mm.find(prefix_placeholder_bytes) != -1:
             yield (prefix_placeholder, mode, f)
         mm.close() and fi.close()

tests/test_build.py

@@ -0,0 +1,40 @@
+"""
+This file tests prefix finding for Windows and *nix.
+"""
+
+import os
+import sys
+
+from conda_build import build
+from conda.compat import TemporaryDirectory
+
+prefix_tests = {"normal": os.path.sep}
+if sys.platform == "win32":
+    prefix_tests.update({"double_backslash": "\\\\",
+                         "forward_slash": "/"})
+
+
+def _write_prefix(filename, prefix, replacement):
+    with open(filename, "w") as f:
+        f.write(prefix.replace(os.path.sep, replacement))
+        f.write("\n")
+
+
+def test_find_prefix_files():
+    """
+    Write test output that has the prefix to be found, then verify that the prefix finding
+    identified the correct number of files.
+    """
+    # create a temporary folder
+    prefix = os.path.join(sys.prefix, "envs", "_build")
+    if not os.path.isdir(prefix):
+        os.makedirs(prefix)
+    with TemporaryDirectory(prefix=prefix + os.path.sep) as tmpdir:
+        # create text files to be replaced
+        files = []
+        for slash_style in prefix_tests:
+            filename = os.path.join(tmpdir, "%s.txt" % slash_style)
+            _write_prefix(filename, prefix, prefix_tests[slash_style])
+            files.append(filename)
+
+        assert len(list(build.have_prefix_files(files))) == len(files)