coredata: Correctly handle receiving a pipe for native/cross files

* coredata: Correctly handle receiving a pipe for native/cross files

In some cases a cross/native file may be a pipe, such as when using bash
process replacement `meson --native-file
<([binaries]llvm-config='/opt/bin/llvm-config')`, for example. In this
case we copy the contents of the pipe into a file in the meson-private
directory so we can create a proper ninja dependency, and be able to
reload the file on --wipe/--reconfigure. This requires some extra
negotiation to preserve these native/cross files.

Fixes #5505

* run_unitests: Add a unit test for native files that are pipes

Using mkfifo.

1 files changed, 2 insertions, 1 deletions

diff --git a/mesonbuild/environment.py b/mesonbuild/environment.py
index 4e2ff92..555c21c 100644
--- a/mesonbuild/environment.py
+++ b/mesonbuild/environment.py
@@ -403,6 +403,7 @@ class Environment:
                     raise e
         else:
             # Just create a fresh coredata in this case
+            self.scratch_dir = ''
             self.create_new_coredata(options)
 
         ## locally bind some unfrozen configuration
@@ -514,7 +515,7 @@ class Environment:
         # WARNING: Don't use any values from coredata in __init__. It gets
         # re-initialized with project options by the interpreter during
         # build file parsing.
-        self.coredata = coredata.CoreData(options)
+        self.coredata = coredata.CoreData(options, self.scratch_dir)
         # Used by the regenchecker script, which runs meson
         self.coredata.meson_command = mesonlib.meson_command
         self.first_invocation = True