From 5b4fd92cdda6a39fb17e35ef25b85e7e156e25ab Mon Sep 17 00:00:00 2001
From: Joel Rosdahl <joel@rosdahl.net>
Date: Fri, 10 Jun 2022 16:12:27 +0200
Subject: [PATCH] feat: Set CCACHE_DISABLE when calling compiler

If ccache for some reason executes a compiler that in turn calls ccache
then ccache will be run twice (and will potentially store two different
result in the cache since the compiler identications differ), which is
not very useful. This could for instance happen if the compiler is a
wrapper script that in turn calls "ccache $compiler ...".

Improve this by setting CCACHE_DISABLE when executing the compiler. Any
subsequent ccache invocations will then fall back to running the real
compiler.
---
 src/ccache.cpp        |  6 ++++++
 test/suites/base.bash | 31 +++++++++++++++----------------
 2 files changed, 21 insertions(+), 16 deletions(-)

diff --git a/src/ccache.cpp b/src/ccache.cpp
index f17631355..630513818 100644
--- a/src/ccache.cpp
+++ b/src/ccache.cpp
@@ -2165,6 +2165,12 @@ do_cache_compilation(Context& ctx, const char* const* argv)
 
   LOG("Compiler type: {}", compiler_type_to_string(ctx.config.compiler_type()));
 
+  // Set CCACHE_DISABLE so no process ccache executes from now on will risk
+  // calling ccache second time. For instance, if the real compiler is a wrapper
+  // script that calls "ccache $compiler ..." we want that inner ccache call to
+  // be disabled.
+  Util::setenv("CCACHE_DISABLE", "1");
+
   MTR_BEGIN("main", "process_args");
   ProcessArgsResult processed = process_args(ctx);
   MTR_END("main", "process_args");
diff --git a/test/suites/base.bash b/test/suites/base.bash
index 89cddf3e8..754649d1c 100644
--- a/test/suites/base.bash
+++ b/test/suites/base.bash
@@ -788,6 +788,21 @@ b"
         expect_stat cache_miss 2
     fi
 
+    # -------------------------------------------------------------------------
+    TEST "CCACHE_DISABLE set when executing compiler"
+
+    cat >compiler.sh <<EOF
+#!/bin/sh
+printf "%s" "\${CCACHE_DISABLE}" >>CCACHE_DISABLE.value
+exec $COMPILER "\$@"
+EOF
+    chmod +x compiler.sh
+    backdate compiler.sh
+    $CCACHE ./compiler.sh -c test1.c
+    expect_stat preprocessed_cache_hit 0
+    expect_stat cache_miss 1
+    expect_content CCACHE_DISABLE.value '11' # preprocessor + compiler
+
     # -------------------------------------------------------------------------
     TEST "CCACHE_COMPILER"
 
@@ -867,8 +882,6 @@ EOF
 
     cat >compiler.sh <<EOF
 #!/bin/sh
-CCACHE_DISABLE=1 # If $COMPILER happens to be a ccache symlink...
-export CCACHE_DISABLE
 exec $COMPILER "\$@"
 # A comment
 EOF
@@ -896,8 +909,6 @@ EOF
 
     cat >compiler.sh <<EOF
 #!/bin/sh
-CCACHE_DISABLE=1 # If $COMPILER happens to be a ccache symlink...
-export CCACHE_DISABLE
 exec $COMPILER "\$@"
 EOF
     chmod +x compiler.sh
@@ -920,8 +931,6 @@ EOF
 
     cat >compiler.sh <<EOF
 #!/bin/sh
-CCACHE_DISABLE=1 # If $COMPILER happens to be a ccache symlink...
-export CCACHE_DISABLE
 exec $COMPILER "\$@"
 EOF
     chmod +x compiler.sh
@@ -944,8 +953,6 @@ EOF
 
     cat >compiler.sh <<EOF
 #!/bin/sh
-CCACHE_DISABLE=1 # If $COMPILER happens to be a ccache symlink...
-export CCACHE_DISABLE
 exec $COMPILER "\$@"
 EOF
     chmod +x compiler.sh
@@ -971,8 +978,6 @@ EOF
 
     cat >compiler.sh <<EOF
 #!/bin/sh
-CCACHE_DISABLE=1 # If $COMPILER happens to be a ccache symlink...
-export CCACHE_DISABLE
 exec $COMPILER "\$@"
 EOF
     chmod +x compiler.sh
@@ -1005,8 +1010,6 @@ EOF
 
     cat >compiler.sh <<EOF
 #!/bin/sh
-CCACHE_DISABLE=1 # If $COMPILER happens to be a ccache symlink...
-export CCACHE_DISABLE
 exec $COMPILER "\$@"
 EOF
     chmod +x compiler.sh
@@ -1255,8 +1258,6 @@ if [ \$1 != -E ]; then
     printf "cc_err|" >&2
     printf "cc_out|"
 fi
-CCACHE_DISABLE=1 # If $COMPILER happens to be a ccache symlink...
-export CCACHE_DISABLE
 exec $COMPILER "\$@"
 EOF
     chmod +x compiler.sh
@@ -1450,8 +1451,6 @@ EOF
 
     cat >buggy-cpp <<EOF
 #!/bin/sh
-CCACHE_DISABLE=1 # If $COMPILER happens to be a ccache symlink...
-export CCACHE_DISABLE
 if echo "\$*" | grep -- -D >/dev/null; then
   $COMPILER "\$@"
 else
-- 
2.47.2