From 9a2357c70b7a704877515c0a4418a85a5ccecfcd Mon Sep 17 00:00:00 2001
From: kitsunyan
Date: Tue, 13 Mar 2018 04:49:38 +0300
Subject: Fix dependency resolver for dependency cycles

X provides Y, X depends on Z, Z depends on Y (X and Y — actual
packages). Before this commit, resolver wouldn't lookup for Y since it's
already provided by X.
---
 src/feature/syncinstall.nim | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

(limited to 'src/feature/syncinstall.nim')

diff --git a/src/feature/syncinstall.nim b/src/feature/syncinstall.nim
index 5f6e082..06ea1d2 100644
--- a/src/feature/syncinstall.nim
+++ b/src/feature/syncinstall.nim
@@ -67,6 +67,17 @@ proc orderInstallation(pkgInfos: seq[PackageInfo],
 proc findDependencies(config: Config, handle: ptr AlpmHandle, dbs: seq[ptr AlpmDatabase],
   satisfied: Table[PackageReference, SatisfyResult], unsatisfied: seq[PackageReference],
   printMode: bool, noaur: bool): (Table[PackageReference, SatisfyResult], seq[PackageReference]) =
+  proc checkDependencyCycle(pkgInfo: PackageInfo, reference: PackageReference): bool =
+    for checkReference in pkgInfo.allDepends:
+      if checkReference.arch.isNone or checkReference.arch == some(config.arch):
+        if checkReference.reference == reference:
+          return false
+        let buildPkgInfo = satisfied.opt(checkReference.reference)
+          .map(r => r.buildPkgInfo).flatten
+        if buildPkgInfo.isSome and not checkDependencyCycle(buildPkgInfo.unsafeGet, reference):
+          return false
+    return true
+
   proc findInSatisfied(reference: PackageReference): Option[PackageInfo] =
     for satref, res in satisfied.pairs:
       if res.buildPkgInfo.isSome:
@@ -76,7 +87,8 @@ proc findDependencies(config: Config, handle: ptr AlpmHandle, dbs: seq[ptr AlpmD
           return some(pkgInfo)
         for provides in pkgInfo.provides:
           if provides.arch.isNone or provides.arch == some(config.arch):
-            if reference.isProvidedBy(provides.reference):
+            if reference.isProvidedBy(provides.reference) and
+              checkDependencyCycle(pkgInfo, reference):
               return some(pkgInfo)
     return none(PackageInfo)
 
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