Fix #824: Refactor pmb/build/package.py (make depends work like in abuild) (#935)

* Rename pmb/build/package.py to pmb/build/_package.py, so we can
  access the functions it contains in testcases, and still use
  pmb.build.package()
* Refactor the entire file. Instead of one big function that does
  too many things, we have many small ones now, that are tested
  in the testsuite and easier to modify
* Whenever building a package, pmbootstrap does not only build and
  install the "makedepends" (like we did before), now it does the
  same for the "depends". That's required to be compatible with
  abuild. The old behavior can still be used with 'pmbootstrap
  build --ignore-depends'.
* Because of that change, noarch packages can no longer be built in
  the native chroot if we need them for a foreign chroot. A device-
  package depending on a kernel would pull in the same kernel for
  the native architecture otherwise.
* Running 'pmbootstrap build device-...' without '--ignore-depends'
  and without a matching '--arch' displays a note that explains
  this change to the user and tells how to use it instead.
* Noarch packages no longer get symlinked. That was only
  implemented for packages built in the native chroot, and now that
  is not always the case anymore. Symlinking these packages creates
  packages with broken dependencies anyway (e.g.
  device-samsung-i9100 can't be installed in x86_64, because
  linux-samsung-i9100 is armhf only).
* Rename "carch" to "arch" wherever used. Naming it "carch"
  sometimes is confusing with no benefit.
* Add a testcase for the aarch64 qemu workaround (because it failed
  first and I needed to know for sure if it is working again).
* Improved some verbose logging, which helped with development of
  this feature.
* Removed the old "build" test case (which was disabled in
  testcases_fast.sh) as the new "build_package" test case covers its
  functionallity.
* Only build indexes if the packages folder exists for that arch (Travis
  couldn't run a test case otherwise)

pmb/helpers/frontend.py

@@ -42,6 +42,50 @@ import pmb.parse
 import pmb.qemu
 
 
+def _build_verify_usage_device_package(args, pkgname):
+    """
+    Detect if the user is about to build a device- package for the wrong
+    architecture. The package is noarch, but the dependencies (kernel!) will get
+    pulled in with the same arch as dependency.
+    """
+    # Skip non-device-packages
+    if not pkgname.startswith("device-"):
+        return
+
+    # Only continue when the --arch parameter is *not* the device architecture
+    deviceinfo = args.aports + "/device/" + pkgname + "/deviceinfo"
+    if not os.path.exists(deviceinfo):
+        return
+    device = pkgname.split("-", 1)[1]
+    arch = pmb.parse.deviceinfo(args, device)["arch"]
+    if args.arch == arch:
+        return
+
+    # Abort with a big note
+    logging.info("Dependency handling in 'pmbootstrap build' has been"
+                 " changed.")
+    logging.info("Previously we only built and installed the 'makedepends'"
+                 " from the APKBUILDs, now we use the 'depends', too.")
+    logging.info("")
+    logging.info("Your options:")
+    logging.info("* Ignore depends (fast, old behavior, may cause problems"
+                 " with some packages):")
+    logging.info("  pmbootstrap build " + pkgname + " -i")
+    logging.info("* Build with depends (kernel!) and specify the right"
+                 " architecture:")
+    logging.info("  pmbootstrap build " + pkgname + " --arch=" + arch)
+    logging.info("")
+    logging.info("This change was necessary to be more compatible with Alpine's"
+                 " abuild.")
+    logging.info("The default architecture is the native one (" +
+                 args.arch_native + " in your case), so you need to overwrite")
+    logging.info("it now to get the kernel dependency of your device package"
+                 " for the right architecture.")
+    logging.info("Sorry for the inconvenience.")
+    logging.info("")
+    raise RuntimeError("Missing -i or --arch parameter")
+
+
 def _parse_flavor(args):
     """
     Verify the flavor argument if specified, or return a default value.
@@ -86,8 +130,16 @@ def aportgen(args):
 
 
 def build(args):
+    # Strict mode: zap everything
     if args.strict:
         pmb.chroot.zap(args, False)
+
+    # Detect wrong usage for device- packages
+    if not args.ignore_depends:
+        for package in args.packages:
+            _build_verify_usage_device_package(args, package)
+
+    # Build all packages
     for package in args.packages:
         pmb.build.package(args, package, args.arch, args.force,
                           args.buildinfo, args.strict)
@@ -136,8 +188,7 @@ def config(args):
 
 
 def index(args):
-    pmb.build.index_repo(args, args.arch_native)
-    pmb.build.symlink_noarch_packages(args)
+    pmb.build.index_repo(args)
 
 
 def initfs(args):