Write relative find-links opts to output file

If input file or command line has `--find-links` options that point to
directories which are relative to the destination file (i.e. relative
path from destination directory to find-links directory does not contain
any `../` components), then those should be written to the output file.

Now `--find-links` options in the source file work similarly as e.g.
the `--extra-index-url` options.  This makes it possible to make deploy
scripts to install from `requirements.txt` without knowing about the
find-links options.

piptools/scripts/compile.py

@@ -230,6 +230,7 @@ def cli(verbose, dry_run, pre, rebuild, find_links, index_url, extra_index_url,
                           index_urls=repository.finder.index_urls,
                           trusted_hosts=pip_options.trusted_hosts,
                           format_control=repository.finder.format_control,
+                          find_links=repository.finder.find_links,
                           allow_unsafe=allow_unsafe)
     writer.write(results=results,
                  reverse_dependencies=reverse_dependencies,

piptools/writer.py

@@ -11,7 +11,7 @@
 class OutputWriter(object):
     def __init__(self, src_files, dst_file, dry_run, emit_header, emit_index,
                  annotate, generate_hashes, default_index_url, index_urls,
-                 trusted_hosts, format_control, allow_unsafe=False):
+                 trusted_hosts, find_links, format_control, allow_unsafe=False):
         self.src_files = src_files
         self.dst_file = dst_file
         self.dry_run = dry_run
@@ -22,6 +22,7 @@ def __init__(self, src_files, dst_file, dry_run, emit_header, emit_index,
         self.default_index_url = default_index_url
         self.index_urls = index_urls
         self.trusted_hosts = trusted_hosts
+        self.find_links = find_links
         self.format_control = format_control
         self.allow_unsafe = allow_unsafe
 
@@ -58,6 +59,18 @@ def write_trusted_hosts(self):
         for trusted_host in self.trusted_hosts:
             yield '--trusted-host {}'.format(trusted_host)
 
+    def write_find_links(self):
+        yielded = set()
+        dst_dir = os.path.dirname(self.dst_file)
+        for abs_link in self.find_links:
+            rel_link = os.path.relpath(abs_link, start=dst_dir)
+            if not rel_link.startswith(os.path.pardir + os.path.sep):
+                # Only yield links which are relative to dst_file, since
+                # absolute paths shouldn't be stored to requirements.txt
+                if rel_link not in yielded:
+                    yield '--find-links {}'.format(rel_link)
+                    yielded.add(rel_link)
+
     def write_format_controls(self):
         for nb in self.format_control.no_binary:
             yield '--no-binary {}'.format(nb)
@@ -68,6 +81,7 @@ def write_flags(self):
         emitted = False
         for line in chain(self.write_index_options(),
                           self.write_trusted_hosts(),
+                          self.write_find_links(),
                           self.write_format_controls()):
             emitted = True
             yield line

tests/test_cli.py

@@ -69,10 +69,21 @@ def test_find_links_option(pip_conf):
     runner = CliRunner()
     with runner.isolated_filesystem():
         open('requirements.in', 'w').close()
-        out = runner.invoke(cli, ['-v', '-f', './libs1', '-f', './libs2'])
+        find_link_options = [
+            '-f', './libs1',
+            '-f', '/global-libs',
+            '-f', './libs2',
+        ]
+        out = runner.invoke(cli, ['-v'] + find_link_options)
 
         # Check that find-links has been passed to pip
-        assert 'Configuration:\n  -f ./libs1\n  -f ./libs2' in out.output
+        assert ('Configuration:\n'
+                '  -f ./libs1\n'
+                '  -f /global-libs\n'
+                '  -f ./libs2\n') in out.output
+
+        assert ('--find-links libs1\n'
+                '--find-links libs2\n') in out.output
 
 
 def test_extra_index_option(pip_conf):

tests/test_writer.py

@@ -12,6 +12,7 @@ def writer():
                         generate_hashes=False,
                         default_index_url=None, index_urls=[],
                         trusted_hosts=[],
+                        find_links=[],
                         format_control=FormatControl(set(), set()))