Merge branch 'lazy-reproducible-builds'

We have "lazy reproducible builds" now. What I mean by that is, that
the resulting "apk" archive is not fully reproducible, but all binaries
inside it are. This is necessary to kick-off the binary repo, which is
in turn required to get the testsuite going on Travis. Read #64 for more
information.

Usage:
```
pmbootstrap build hello-world --buildinfo
pmbootstrap challenge /tmp/path/to/hello-world-1-r2.apk
```

The "--buildinfo" parameter generates a "buildinfo.json", which contains
the versions of all dependencies. It is not very optimizied, so this
is a performance bottleneck and takes 10 seconds (which is quite much
considering that the hello-world package builds in less than a second).
This can be improved in the future, and then the buildinfo parameter
may become the default.

pmb/parse/apkbuild.py

@@ -37,7 +37,7 @@ def replace_variables(apkbuild):
         replaced.append(subpackage.replace("$pkgname", ret["pkgname"]))
     ret["subpackages"] = replaced
 
-    # makedepend: $makedepends_host, $makedepends_build, $_llvmver
+    # makedepends: $makedepends_host, $makedepends_build, $_llvmver
     replaced = []
     for makedepend in ret["makedepends"]:
         if makedepend.startswith("$"):

pmb/parse/apkindex.py

@@ -74,6 +74,17 @@ def read(args, package, path, must_exist=True):
                         if not ret or compare_version(current["version"],
                                                       ret["version"]) == 1:
                             ret = current
+                    if "provides" in current:
+                        for alias in current["provides"]:
+                            split = alias.split("=")
+                            if len(split) == 1:
+                                continue
+                            name = split[0]
+                            version = split[1]
+                            if name == package:
+                                if not ret or compare_version(current["version"],
+                                                              version) == 1:
+                                    ret = current
                     current = {}
                 if line.startswith("P:"):  # package
                     current["pkgname"] = line[2:-1]
@@ -85,8 +96,17 @@ def read(args, package, path, must_exist=True):
                         current["depends"] = depends.split(" ")
                     else:
                         current["depends"] = []
+                if line.startswith("p:"):  # provides
+                    provides = line[2:-1]
+                    current["provides"] = provides.split(" ")
     if not ret and must_exist:
         raise RuntimeError("Package " + package + " not found in " + path)
+
+    if ret:
+        for key in ["depends", "provides"]:
+            if key not in ret:
+                ret[key] = []
+
     return ret
 
 

pmb/parse/arguments.py

@@ -61,7 +61,9 @@ def arguments_initfs(subparser):
     # ls, build, extract
     ls = sub.add_parser("ls", help="list initramfs contents")
     build = sub.add_parser("build", help="(re)build the initramfs")
-    extract = sub.add_parser("extract", help="extract the initramfs to a temporary folder")
+    extract = sub.add_parser(
+        "extract",
+        help="extract the initramfs to a temporary folder")
     for action in [ls, build, extract]:
         action.add_argument(
             "--flavor",
@@ -164,9 +166,15 @@ def arguments():
                            " specific architecture")
     build.add_argument("--arch")
     build.add_argument("--force", action="store_true")
+    build.add_argument("--buildinfo", action="store_true")
     for action in [checksum, build, menuconfig, parse_apkbuild, aportgen]:
         action.add_argument("package")
 
+    # Action: challenge
+    challenge = sub.add_parser("challenge",
+                               help="rebuild a package and diff its contents")
+    challenge.add_argument("apk")
+
     # Use defaults from the user's config file
     args = parser.parse_args()
     cfg = pmb.config.load(args)