From 62503bbd9e82a5b0fdeec6e357a95e724ec3cef6 Mon Sep 17 00:00:00 2001
From: Fabian Groffen <grobian@gentoo.org>
Date: Wed, 15 Jun 2022 21:53:43 +0200
Subject: libq/atom: fix atom_compare for "0" version components

Bug: https://bugs.gentoo.org/852197
Signed-off-by: Fabian Groffen <grobian@gentoo.org>
---
 libq/atom.c                     | 36 ++++++++++++++++++++++++++----------
 tests/atom_compare/static.good  |  1 +
 tests/atom_compare/static.tests |  1 +
 3 files changed, 28 insertions(+), 10 deletions(-)

diff --git a/libq/atom.c b/libq/atom.c
index 50e9520..31299f1 100644
--- a/libq/atom.c
+++ b/libq/atom.c
@@ -784,22 +784,38 @@ atom_compare_flg(const depend_atom *data, const depend_atom *query, int flags)
 							 *ends1 != '_';
 							 ends1++)
 							;
+						if (ends1 != s1)
+							ends1--;
 						for (ends2 = s2;
 							 *ends2 != '\0' &&
 							 *ends2 != '.' &&
 							 *ends2 != '_';
 							 ends2++)
 							;
-						/* 3.3L2-3: remove *trailing* zeros */
-						for (ends1--; ends1 > s1 && *ends1 == '0'; ends1--)
-							;
-						for (ends2--; ends2 > s2 && *ends2 == '0'; ends2--)
-							;
-						/* 3.3L4 ASCII stringwise comparison */
-						n1 = ends1 - s1;
-						n2 = ends2 - s2;
-						n1 = strncmp(s1, s2, n1 > n2 ? n1 : n2);
-						n2 = 0;
+						if (ends2 != s2)
+							ends2--;
+						/* bug 852197: leading 0 means something else
+						 *              must follow */
+						if (ends1 - s1 > 1 || ends2 - s2 > 1) {
+							/* 3.3L2-3: remove *trailing* zeros */
+							for (; ends1 > s1 && *ends1 == '0'; ends1--)
+								;
+							for (; ends2 > s2 && *ends2 == '0'; ends2--)
+								;
+							/* 3.3L4 ASCII stringwise comparison */
+							n1 = ends1 - s1;
+							n2 = ends2 - s2;
+							n1 = strncmp(s1, s2, n1 > n2 ? n1 : n2);
+							n2 = 0;
+						} else {
+							/* repeat of 3.3#L9 (else case below) */
+							n1 = strtoll(s1, &ends1, 10);
+							if (ends1 == s1)
+								n1 = -1;
+							n2 = strtoll(s2, &ends2, 10);
+							if (ends2 == s2)
+								n2 = -1;
+						}
 					} else {  /* 3.3#L9 */
 						n1 = strtoll(s1, &ends1, 10);
 						if (ends1 == s1)
diff --git a/tests/atom_compare/static.good b/tests/atom_compare/static.good
index 6da5553..83bf7ec 100644
--- a/tests/atom_compare/static.good
+++ b/tests/atom_compare/static.good
@@ -52,3 +52,4 @@ a-1 != =a-1.2z*
 a-1_alpha1 == =a-1*
 a-1 != =a-1_alpha1*
 a-1_alpha-r1 == =a-1_alpha*
+a-3.10.5 == >=a-3.10.0_p1_r1
diff --git a/tests/atom_compare/static.tests b/tests/atom_compare/static.tests
index 168f358..213fb5e 100644
--- a/tests/atom_compare/static.tests
+++ b/tests/atom_compare/static.tests
@@ -52,3 +52,4 @@ a-1 =a-1.2z*
 a-1_alpha1 =a-1*
 a-1 =a-1_alpha1*
 a-1_alpha-r1 =a-1_alpha*
+a-3.10.5 >=a-3.10.0_p1_r1
-- 
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