From 81126fa4102362fe799b2ce2f125558a2f5b7d6b Mon Sep 17 00:00:00 2001
From: Peter Josef Scheibel <scheibel1@llnl.gov>
Date: Thu, 8 Feb 2024 17:44:50 -0800
Subject: [PATCH] add spack-python script to output diff in tree format

---
 lib/scripts/altdiff.py | 127 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 127 insertions(+)
 create mode 100644 lib/scripts/altdiff.py

diff --git a/lib/scripts/altdiff.py b/lib/scripts/altdiff.py
new file mode 100644
index 000000000..b252e3bfe
--- /dev/null
+++ b/lib/scripts/altdiff.py
@@ -0,0 +1,127 @@
+import spack.cmd
+import spack.environment as ev
+import spack.traverse as traverse
+from llnl.util.tty.color import cwrite
+
+import sys
+
+
+def diff_specs(spec_a, spec_b):
+    def highlight(element):
+        cwrite("@R{%s}" % str(element))
+
+    def _write(s):
+        print(s, end="")
+
+    def _variant_str(v):
+        if isinstance(v, spack.variant.BoolValuedVariant):
+            return str(v)
+        else:
+            return " " + str(v)
+
+    class VariantsComparator:
+        def __init__(self, spec):
+            self.variants = spec.variants
+
+        def compare(self, other_spec):
+            if not self.variants:
+                return
+            for k, v in self.variants.items():
+                if k not in other_spec.variants:
+                    highlight(_variant_str(v))
+                elif not v.satisfies(other_spec.variants[k]):
+                    highlight(_variant_str(v))
+                else:
+                    _write(_variant_str(v))
+
+    class VersionComparator:
+        def __init__(self, spec):
+            self.version = spec.version
+
+        def compare(self, other_spec):
+            other_version = other_spec.version
+            if self.version.satisfies(other_version):
+                _write(f"@{self.version}")
+            else:
+                highlight(f"@{self.version}")
+
+    class CompilerComparator:
+        def __init__(self, spec):
+            self.compiler = spec.compiler
+
+        def compare(self, other_spec):
+            other_cmp = other_spec.compiler
+            if self.compiler.name == other_cmp.name:
+                _write(f"%{self.compiler.name}")
+                if self.compiler.version.satisfies(other_cmp.version):
+                    _write(f"@{self.compiler.version}")
+                else:
+                    highlight(f"@{self.compiler.version}")
+            else:
+                highlight(f"%{self.compiler}")
+
+    class DepsComparator:
+        def __init__(self, spec, newline_cb):
+            self.spec = spec
+            self.newline_cb = newline_cb
+
+        def compare(self, other_spec):
+            self_deps = set(x.name for x in self.spec.dependencies())
+            other_deps = set(x.name for x in other_spec.dependencies())
+            extra = list(sorted(self_deps - other_deps))
+            if extra:
+                self.newline_cb()
+                highlight(f"-> [{' '.join(extra)}]")
+
+    class NewlineWithDepthIndent:
+        def __init__(self):
+            self.depth = 0
+
+        def __call__(self):
+            print()
+            _write("  " * self.depth)
+
+    nl_cb = NewlineWithDepthIndent()
+
+    def decompose(spec):
+        return [
+            VersionComparator(spec),
+            CompilerComparator(spec),
+            VariantsComparator(spec),
+            DepsComparator(spec, nl_cb)
+        ]
+
+    for depth, dep_spec in traverse.traverse_tree([spec_a], deptype=("link", "run"), depth_first=True):
+        indent = "  " * depth
+        nl_cb.depth = depth
+        node = dep_spec.spec
+        _write(indent)
+        if node.name in spec_b:
+            _write(node.name)
+
+            comparators = decompose(node)
+            for c in comparators:
+                c.compare(spec_b[node.name])
+        else:
+            highlight(node.name)
+        print()  # New line
+
+def main():
+    env = ev.active_environment()
+
+    specs = []
+    for spec in spack.cmd.parse_specs(sys.argv[1:]):
+        # If the spec has a hash, check it before disambiguating
+        spec.replace_hash()
+        if spec.concrete:
+            specs.append(spec)
+        else:
+            specs.append(spack.cmd.disambiguate_spec(spec, env))
+
+    if len(specs) != 2:
+        raise Exception("Need two specs")
+
+    diff_specs(specs[0], specs[1])
+
+if __name__ == "__main__":
+    main()
\ No newline at end of file