From 62de8651036046379396cf5f72330a6cf991d276 Mon Sep 17 00:00:00 2001
From: Christopher Haster <geky@geky.net>
Date: Wed, 20 Mar 2024 13:31:16 -0500
Subject: [PATCH] Eliminated null tag reachability in dbg scripts

This was throwing off tree rendering in dbglfs.py, we attempt to lookup
the null tag because we just want to first tag in the tree to stitch
things together.

Null tag reachability is tricky! You only notice if the tree happens to
create a hole, which isn't that common. I think all lookup
implementations should have this max(tag, 1) pattern from now on to
avoid this.

Note that most dbg scripts wouldn't run into this because we usually use
the traversal tag+1 pattern. Still, the inconsistency in impl between
the dbg scripts and lfs.c is bad.
---
 scripts/dbgbmap.py  | 1 +
 scripts/dbgbtree.py | 1 +
 scripts/dbglfs.py   | 1 +
 scripts/dbgmtree.py | 1 +
 scripts/dbgrbyd.py  | 1 +
 5 files changed, 5 insertions(+)

diff --git a/scripts/dbgbmap.py b/scripts/dbgbmap.py
index 91474f31..933b1e15 100755
--- a/scripts/dbgbmap.py
+++ b/scripts/dbgbmap.py
@@ -715,6 +715,7 @@ class Rbyd:
         if not self:
             return True, 0, -1, 0, 0, 0, b'', []
 
+        tag = max(tag, 0x1)
         lower = 0
         upper = self.weight
         path = []
diff --git a/scripts/dbgbtree.py b/scripts/dbgbtree.py
index 0a901dbb..bcc498a6 100755
--- a/scripts/dbgbtree.py
+++ b/scripts/dbgbtree.py
@@ -375,6 +375,7 @@ class Rbyd:
         if not self:
             return True, 0, -1, 0, 0, 0, b'', []
 
+        tag = max(tag, 0x1)
         lower = 0
         upper = self.weight
         path = []
diff --git a/scripts/dbglfs.py b/scripts/dbglfs.py
index 721eacab..cd4f2cc0 100755
--- a/scripts/dbglfs.py
+++ b/scripts/dbglfs.py
@@ -406,6 +406,7 @@ class Rbyd:
         if not self:
             return True, 0, -1, 0, 0, 0, b'', []
 
+        tag = max(tag, 0x1)
         lower = 0
         upper = self.weight
         path = []
diff --git a/scripts/dbgmtree.py b/scripts/dbgmtree.py
index 807ed6c6..07ab0dd9 100755
--- a/scripts/dbgmtree.py
+++ b/scripts/dbgmtree.py
@@ -390,6 +390,7 @@ class Rbyd:
         if not self:
             return True, 0, -1, 0, 0, 0, b'', []
 
+        tag = max(tag, 0x1)
         lower = 0
         upper = self.weight
         path = []
diff --git a/scripts/dbgrbyd.py b/scripts/dbgrbyd.py
index 50beb0b4..46d03ebb 100755
--- a/scripts/dbgrbyd.py
+++ b/scripts/dbgrbyd.py
@@ -614,6 +614,7 @@ def dbg_tree(data, block_size, rev, trunk, weight, *,
     # lookup a tag, returning also the search path for decoration
     # purposes
     def lookup(rid, tag):
+        tag = max(tag, 0x1)
         lower = 0
         upper = weight
         path = []