From 40863a594372ede117533d5c0970a96d60e34371 Mon Sep 17 00:00:00 2001
From: Boris Kolpackov <boris@codesynthesis.com>
Date: Thu, 22 Apr 2021 10:10:34 +0200
Subject: Incorporate project environment checksum into cc::compiler_info cache
 key

---
 libbuild2/bin/guess.cxx | 12 ++++++++++++
 libbuild2/bin/guess.hxx |  9 +++++++++
 2 files changed, 21 insertions(+)

(limited to 'libbuild2/bin')

diff --git a/libbuild2/bin/guess.cxx b/libbuild2/bin/guess.cxx
index 219b8e8..8dd3cb6 100644
--- a/libbuild2/bin/guess.cxx
+++ b/libbuild2/bin/guess.cxx
@@ -363,6 +363,9 @@ namespace build2
     //    will need to figure out what's important (some of them are clearly
     //    for debugging of ld itself).
     //
+    // See also the note on environment and caching below if adding any new
+    // variables.
+    //
     static const char* gnu_ld_env[] = {
       "LD_RUN_PATH", "GNUTARGET", "LDEMULATION", "COLLECT_NO_DEMANGLE", nullptr};
 
@@ -381,6 +384,9 @@ namespace build2
 
       // First check the cache.
       //
+      // Note that none of the information that we cache can be affected by
+      // the environment.
+      //
       string key;
       {
         sha256 cs;
@@ -569,6 +575,9 @@ namespace build2
 
     // Resource compiler environment variables.
     //
+    // See also the note on environment and caching below if adding any new
+    // variables.
+    //
     static const char* msvc_rc_env[] = {"INCLUDE", nullptr};
 
     // Extracting rc information requires running it which can become
@@ -583,6 +592,9 @@ namespace build2
 
       // First check the cache.
       //
+      // Note that none of the information that we cache can be affected by
+      // the environment.
+      //
       string key;
       {
         sha256 cs;
diff --git a/libbuild2/bin/guess.hxx b/libbuild2/bin/guess.hxx
index e5da263..3307999 100644
--- a/libbuild2/bin/guess.hxx
+++ b/libbuild2/bin/guess.hxx
@@ -31,6 +31,9 @@ namespace build2
     // The environment is an optional list of environment variables that
     // affect ar/ranlib result.
     //
+    // Watch out for the environment not to affect any of the extracted
+    // information since we cache it.
+    //
     struct ar_info
     {
       process_path ar_path;
@@ -80,6 +83,9 @@ namespace build2
     // The environment is an optional list of environment variables that
     // affect the linker result.
     //
+    // Watch out for the environment not to affect any of the extracted
+    // information since we cache it.
+    //
     // Note that for now the version is extracted only for some linkers. Once
     // it's done for all of them, we should drop optional.
     //
@@ -113,6 +119,9 @@ namespace build2
     // The environment is an optional list of environment variables that
     // affect the resource compiler result.
     //
+    // Watch out for the environment not to affect any of the extracted
+    // information since we cache it.
+    //
     struct rc_info
     {
       process_path path;
-- 
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