bin/merge-driver-ekeyword: Move logic to a separate module

To facilitate unit testing.

Signed-off-by: Matt Turner <mattst88@gentoo.org>

3 files changed, 145 insertions, 134 deletions

diff --git a/bin/merge-driver-ekeyword b/bin/merge-driver-ekeyword
index 59527bb..53dbcad 100755
--- a/bin/merge-driver-ekeyword
+++ b/bin/merge-driver-ekeyword
@@ -3,141 +3,9 @@
 # Copyright 2020-2024 Gentoo Authors
 # Distributed under the terms of the GNU General Public License v2 or later
 
-"""
-Custom git merge driver for handling conflicts in KEYWORDS assignments
-
-See https://git-scm.com/docs/gitattributes#_defining_a_custom_merge_driver
-"""
-
-import difflib
-import os
-import shutil
 import sys
-import tempfile
-
-from typing import Optional
-from collections.abc import Sequence
-
-from gentoolkit.ekeyword import ekeyword
-
-
-KeywordChanges = list[tuple[Optional[list[str]], Optional[list[str]]]]
-
-
-def keyword_array(keyword_line: str) -> list[str]:
-    # Find indices of string inside the double-quotes
-    i1: int = keyword_line.find('"') + 1
-    i2: int = keyword_line.rfind('"')
-
-    # Split into array of KEYWORDS
-    return keyword_line[i1:i2].split(' ')
-
-
-def keyword_line_changes(old: str, new: str) -> KeywordChanges:
-    a: list[str] = keyword_array(old)
-    b: list[str] = keyword_array(new)
-
-    s = difflib.SequenceMatcher(a=a, b=b)
-
-    changes: KeywordChanges = []
-    for tag, i1, i2, j1, j2 in s.get_opcodes():
-        if tag == 'replace':
-            changes.append((a[i1:i2], b[j1:j2]),)
-        elif tag == 'delete':
-            changes.append((a[i1:i2], None),)
-        elif tag == 'insert':
-            changes.append((None, b[j1:j2]),)
-        else:
-            assert tag == 'equal'
-    return changes
-
-
-def keyword_changes(ebuild1: str, ebuild2: str) -> Optional[KeywordChanges]:
-    with open(ebuild1) as e1, open(ebuild2) as e2:
-        lines1 = e1.readlines()
-        lines2 = e2.readlines()
-
-        diff = difflib.unified_diff(lines1, lines2, n=0)
-        assert next(diff) == '--- \n'
-        assert next(diff) == '+++ \n'
-
-        hunk: int = 0
-        old: str = ''
-        new: str = ''
-
-        for line in diff:
-            if line.startswith('@@ '):
-                if hunk > 0:
-                    break
-                hunk += 1
-            elif line.startswith('-'):
-                if old or new:
-                    break
-                old = line
-            elif line.startswith('+'):
-                if not old or new:
-                    break
-                new = line
-        else:
-            if 'KEYWORDS=' in old and 'KEYWORDS=' in new:
-                return keyword_line_changes(old, new)
-        return None
-
-
-def apply_keyword_changes(ebuild: str, pathname: str,
-                          changes: KeywordChanges) -> int:
-    result: int = 0
-
-    with tempfile.TemporaryDirectory() as tmpdir:
-        # ekeyword will only modify files named *.ebuild, so make a symlink
-        ebuild_symlink: str = os.path.join(tmpdir, os.path.basename(pathname))
-        os.symlink(os.path.join(os.getcwd(), ebuild), ebuild_symlink)
-
-        for removals, additions in changes:
-            args = []
-            if removals:
-                for rem in removals:
-                    # Drop leading '~' and '-' characters and prepend '^'
-                    i = 1 if rem[0] in ('~', '-') else 0
-                    args.append('^' + rem[i:])
-            if additions:
-                args.extend(additions)
-            args.append(ebuild_symlink)
-
-            result = ekeyword.main(args)
-            if result != 0:
-                break
-
-    return result
-
-
-def main(argv: Sequence[str]) -> int:
-    if len(argv) != 4:
-        return -1
-
-    O = argv[0]  # %O - filename of original
-    A = argv[1]  # %A - filename of our current version
-    B = argv[2]  # %B - filename of the other branch's version
-    P = argv[3]  # %P - original path of the file
 
-    # Get changes to KEYWORDS= from %O to %B
-    if changes := keyword_changes(O, B):
-        # Apply %O -> %B changes to %A
-        result = apply_keyword_changes(A, P, changes)
-        return result
-    # Get changes to KEYWORDS= from %O to %A
-    elif changes := keyword_changes(O, A):
-        # Apply %O -> %A changes to %B
-        result = apply_keyword_changes(B, P, changes)
-        # Merged file should be left in %A
-        shutil.move(B, A)
-        return result
-    else:
-        try:
-            os.execlp("git", "git", "merge-file", "-L", "HEAD", "-L", "base", "-L", "ours", A, O, B)
-        except OSError:
-            return -1
+from gentoolkit.merge_driver_ekeyword import merge_driver_ekeyword
 
 
-if __name__ == "__main__":
-    sys.exit(main(sys.argv[1:]))
+sys.exit(merge_driver_ekeyword.main(sys.argv[1:]))
diff --git a/pym/gentoolkit/merge_driver_ekeyword/__init__.py b/pym/gentoolkit/merge_driver_ekeyword/__init__.py
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/pym/gentoolkit/merge_driver_ekeyword/__init__.py
diff --git a/pym/gentoolkit/merge_driver_ekeyword/merge_driver_ekeyword.py b/pym/gentoolkit/merge_driver_ekeyword/merge_driver_ekeyword.py
new file mode 100755
index 0000000..59527bb
--- /dev/null
+++ b/pym/gentoolkit/merge_driver_ekeyword/merge_driver_ekeyword.py
@@ -0,0 +1,143 @@
+#!/usr/bin/python3
+#
+# Copyright 2020-2024 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2 or later
+
+"""
+Custom git merge driver for handling conflicts in KEYWORDS assignments
+
+See https://git-scm.com/docs/gitattributes#_defining_a_custom_merge_driver
+"""
+
+import difflib
+import os
+import shutil
+import sys
+import tempfile
+
+from typing import Optional
+from collections.abc import Sequence
+
+from gentoolkit.ekeyword import ekeyword
+
+
+KeywordChanges = list[tuple[Optional[list[str]], Optional[list[str]]]]
+
+
+def keyword_array(keyword_line: str) -> list[str]:
+    # Find indices of string inside the double-quotes
+    i1: int = keyword_line.find('"') + 1
+    i2: int = keyword_line.rfind('"')
+
+    # Split into array of KEYWORDS
+    return keyword_line[i1:i2].split(' ')
+
+
+def keyword_line_changes(old: str, new: str) -> KeywordChanges:
+    a: list[str] = keyword_array(old)
+    b: list[str] = keyword_array(new)
+
+    s = difflib.SequenceMatcher(a=a, b=b)
+
+    changes: KeywordChanges = []
+    for tag, i1, i2, j1, j2 in s.get_opcodes():
+        if tag == 'replace':
+            changes.append((a[i1:i2], b[j1:j2]),)
+        elif tag == 'delete':
+            changes.append((a[i1:i2], None),)
+        elif tag == 'insert':
+            changes.append((None, b[j1:j2]),)
+        else:
+            assert tag == 'equal'
+    return changes
+
+
+def keyword_changes(ebuild1: str, ebuild2: str) -> Optional[KeywordChanges]:
+    with open(ebuild1) as e1, open(ebuild2) as e2:
+        lines1 = e1.readlines()
+        lines2 = e2.readlines()
+
+        diff = difflib.unified_diff(lines1, lines2, n=0)
+        assert next(diff) == '--- \n'
+        assert next(diff) == '+++ \n'
+
+        hunk: int = 0
+        old: str = ''
+        new: str = ''
+
+        for line in diff:
+            if line.startswith('@@ '):
+                if hunk > 0:
+                    break
+                hunk += 1
+            elif line.startswith('-'):
+                if old or new:
+                    break
+                old = line
+            elif line.startswith('+'):
+                if not old or new:
+                    break
+                new = line
+        else:
+            if 'KEYWORDS=' in old and 'KEYWORDS=' in new:
+                return keyword_line_changes(old, new)
+        return None
+
+
+def apply_keyword_changes(ebuild: str, pathname: str,
+                          changes: KeywordChanges) -> int:
+    result: int = 0
+
+    with tempfile.TemporaryDirectory() as tmpdir:
+        # ekeyword will only modify files named *.ebuild, so make a symlink
+        ebuild_symlink: str = os.path.join(tmpdir, os.path.basename(pathname))
+        os.symlink(os.path.join(os.getcwd(), ebuild), ebuild_symlink)
+
+        for removals, additions in changes:
+            args = []
+            if removals:
+                for rem in removals:
+                    # Drop leading '~' and '-' characters and prepend '^'
+                    i = 1 if rem[0] in ('~', '-') else 0
+                    args.append('^' + rem[i:])
+            if additions:
+                args.extend(additions)
+            args.append(ebuild_symlink)
+
+            result = ekeyword.main(args)
+            if result != 0:
+                break
+
+    return result
+
+
+def main(argv: Sequence[str]) -> int:
+    if len(argv) != 4:
+        return -1
+
+    O = argv[0]  # %O - filename of original
+    A = argv[1]  # %A - filename of our current version
+    B = argv[2]  # %B - filename of the other branch's version
+    P = argv[3]  # %P - original path of the file
+
+    # Get changes to KEYWORDS= from %O to %B
+    if changes := keyword_changes(O, B):
+        # Apply %O -> %B changes to %A
+        result = apply_keyword_changes(A, P, changes)
+        return result
+    # Get changes to KEYWORDS= from %O to %A
+    elif changes := keyword_changes(O, A):
+        # Apply %O -> %A changes to %B
+        result = apply_keyword_changes(B, P, changes)
+        # Merged file should be left in %A
+        shutil.move(B, A)
+        return result
+    else:
+        try:
+            os.execlp("git", "git", "merge-file", "-L", "HEAD", "-L", "base", "-L", "ours", A, O, B)
+        except OSError:
+            return -1
+
+
+if __name__ == "__main__":
+    sys.exit(main(sys.argv[1:]))