xbps: Make pull-pack updatable

Consider pull-pack to be out of date if the remote repository
has a newer version of the package.

xbstrap/base.py

@@ -1761,6 +1761,19 @@ def check_if_packed(self, settings):
     def check_if_pull_needed(self, settings):
         if self._cfg.use_xbps:
             if self._have_xbps_package():
+                if settings.check_remotes:
+                    # Local repodata exists (otherwise _have_xbps_package() would return false).
+                    rd = self.get_local_xbps_repodata_entry()
+                    if rd is None:
+                        raise RuntimeError("Expected local xbps repodata to exist")
+
+                    remote_rd = self.get_remote_xbps_repodata_entry()
+                    if remote_rd is not None:
+                        version = _xbps_utils.parse_version(rd["pkgver"])
+                        remote_version = _xbps_utils.parse_version(remote_rd["pkgver"])
+                        if _xbps_utils.compare_version(version, remote_version) < 0:
+                            return ItemState(updatable=True)
+
                 return ItemState()
             else:
                 return ItemState(missing=True)

xbstrap/xbps_utils.py

@@ -1,3 +1,4 @@
+import itertools
 import plistlib
 import shlex
 import tarfile
@@ -18,6 +19,90 @@ def read_repodata(path):
                         return pkg_idx
 
 
+class XbpsVersion:
+    def __init__(self, comps, revision=1):
+        self.comps = comps
+        self.revision = revision
+
+
+# This matches the version parsing algorithm in xbps.
+def parse_components(v):
+    modifiers = {
+        "alpha": -3,
+        "beta": -2,
+        "pre": -1,
+        "rc": -1,
+        "pl": 0,
+        ".": 0,
+    }
+    alphas = "abcdefghijklmnopqrstuvwxyz"
+
+    n = 0
+    out = []
+
+    def consume_next_token():
+        nonlocal n
+
+        # Integers correspond to a single component.
+        if v[n].isdigit():
+            d = 0
+            while n < len(v) and v[n].isdigit():
+                d = (d * 10) + int(v[n])
+                n += 1
+            out.append(d)
+            return
+
+        # Modifiers correspond to a single component with a fixed value.
+        for modifier, prio in modifiers.items():
+            if v[n:].startswith(modifier):
+                out.append(prio)
+                n += len(modifier)
+                return
+
+        # Letters correspond to two components: (0, idx + 1).
+        # For example: versions "0.2" and "0b" are identical.
+        idx = alphas.find(v[n].lower())
+        if idx >= 0:
+            out.append(0)
+            out.append(idx + 1)
+
+        # Consume the character. It does _not_ contribute to the version.
+        n += 1
+
+    while n < len(v):
+        consume_next_token()
+
+    return out
+
+
+def parse_version(v, *, strip_pkgname=True):
+    if strip_pkgname:
+        v = v.split("-")[-1]
+
+    # Split into components + revision.
+    # Technically, xbps's parsing code allows the revision to appear in the middle of a version.
+    # We only accept revision at the end of a version string.
+    parts = v.split("_")
+    comps = parse_components(parts[0])
+    if len(parts) > 1:
+        if len(parts) != 2:
+            raise RuntimeError("Expected at most one revision in xbps version")
+        revision = int(parts[1])
+    else:
+        revision = 1
+
+    return XbpsVersion(comps, revision)
+
+
+def compare_version(v1, v2):
+    for c1, c2 in itertools.zip_longest(v1.comps, v2.comps, fillvalue=0):
+        if c1 != c2:
+            return c1 - c2
+    if v1.revision != v2.revision:
+        return v1.revision - v2.revision
+    return 0
+
+
 # XBPS INSTALL/REMOVE scripts are called with arguments:
 # <action> <pkgname> <version> <update yes/no> "no" <arch>