From 15f7bdaf276252f7b536c189b9b3eef73ad0e6e7 Mon Sep 17 00:00:00 2001
From: Robert Hensing <robert@roberthensing.nl>
Date: Fri, 12 Jan 2024 22:55:37 +0100
Subject: [PATCH] CanonPath: Add rel_c_str()

Defensively because isRoot() is also defensive.
---
 src/libfetchers/git-utils.cc | 3 +--
 src/libutil/canon-path.hh    | 7 +++++++
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/src/libfetchers/git-utils.cc b/src/libfetchers/git-utils.cc
index bfc7059fe..6726407b5 100644
--- a/src/libfetchers/git-utils.cc
+++ b/src/libfetchers/git-utils.cc
@@ -674,8 +674,7 @@ struct GitExportIgnoreInputAccessor : CachingFilteringInputAccessor {
 
     bool gitAttrGet(const CanonPath & path, const char * attrName, const char * & valueOut)
     {
-        std::string pathStr {path.rel()};
-        const char * pathCStr = pathStr.c_str();
+        const char * pathCStr = path.rel_c_str();
 
         if (rev) {
             git_attr_options opts = GIT_ATTR_OPTIONS_INIT;
diff --git a/src/libutil/canon-path.hh b/src/libutil/canon-path.hh
index 6aff4ec0d..997c8c731 100644
--- a/src/libutil/canon-path.hh
+++ b/src/libutil/canon-path.hh
@@ -88,6 +88,13 @@ public:
     std::string_view rel() const
     { return ((std::string_view) path).substr(1); }
 
+    const char * rel_c_str() const
+    {
+        auto cs = path.c_str();
+        assert(cs[0]); // for safety if invariant is broken
+        return &cs[1];
+    }
+
     struct Iterator
     {
         std::string_view remaining;