Add a reproducibility option for building ecodes.c (#242)

ecodes.c currently contains the kernel info of the build machine and the
full path of the input*.h headers: This is not reproducible as output
can change even is headers content do not. Downstream distributions
might package ecodes.c and get non-reproducible output.

To fix this: introduce a --reproducible option in the build:
- in setup.py build_ecodes command
- in underlying genecodes_c.py

Note: These options are disabled by default so no change is expected in
current builds.

Signed-off-by: Yoann Congal <yoann.congal@smile.fr>

Author: ycongal-smile

setup.py

@@ -14,7 +14,7 @@
 ecodes_c_path = curdir / "src/evdev/ecodes.c"
 
 
-def create_ecodes(headers=None):
+def create_ecodes(headers=None, reproducibility=False):
     if not headers:
         include_paths = set()
         cpath = os.environ.get("CPATH", "").strip()
@@ -65,7 +65,10 @@ def create_ecodes(headers=None):
 
     print("writing %s (using %s)" % (ecodes_c_path, " ".join(headers)))
     with ecodes_c_path.open("w") as fh:
-        cmd = [sys.executable, "src/evdev/genecodes_c.py", "--ecodes", *headers]
+        cmd = [sys.executable, "src/evdev/genecodes_c.py"]
+        if reproducibility:
+            cmd.append("--reproducibility")
+        cmd.extend(["--ecodes", *headers])
         run(cmd, check=True, stdout=fh)
 
 
@@ -74,17 +77,21 @@ class build_ecodes(Command):
 
     user_options = [
         ("evdev-headers=", None, "colon-separated paths to input subsystem headers"),
+        ("reproducibility", None, "hide host details (host/paths) to create a reproducible output"),
     ]
 
     def initialize_options(self):
         self.evdev_headers = None
+        self.reproducibility = False
 
     def finalize_options(self):
         if self.evdev_headers:
             self.evdev_headers = self.evdev_headers.split(":")
+        if self.reproducibility is None:
+            self.reproducibility = False
 
     def run(self):
-        create_ecodes(self.evdev_headers)
+        create_ecodes(self.evdev_headers, reproducibility=self.reproducibility)
 
 
 class build_ext(_build_ext.build_ext):

src/evdev/genecodes_c.py

@@ -15,22 +15,27 @@
     "/usr/include/linux/uinput.h",
 ]
 
-opts, args = getopt.getopt(sys.argv[1:], "", ["ecodes", "stubs"])
+opts, args = getopt.getopt(sys.argv[1:], "", ["ecodes", "stubs", "reproducibility"])
 if not opts:
-    print("usage: genecodes.py [--ecodes|--stubs] <headers>")
+    print("usage: genecodes.py [--ecodes|--stubs] [--reproducibility] <headers>")
     exit(2)
 
 if args:
     headers = args
 
+reproducibility = ("--reproducibility", "") in opts
+
 
 # -----------------------------------------------------------------------------
 macro_regex = r"#define\s+((?:KEY|ABS|REL|SW|MSC|LED|BTN|REP|SND|ID|EV|BUS|SYN|FF|UI_FF|INPUT_PROP)_\w+)"
 macro_regex = re.compile(macro_regex)
 
-# Uname without hostname.
-uname = list(os.uname())
-uname = " ".join((uname[0], *uname[2:]))
+if reproducibility:
+    uname = "hidden for reproducibility"
+else:
+    # Uname without hostname.
+    uname = list(os.uname())
+    uname = " ".join((uname[0], *uname[2:]))
 
 
 # -----------------------------------------------------------------------------
@@ -138,5 +143,5 @@ def parse_headers(headers=headers):
     template = template_stubs
 
 body = os.linesep.join(body)
-text = template % (uname, headers, body)
+text = template % (uname, headers if not reproducibility else ["hidden for reproducibility"], body)
 print(text.strip())