test case refs #10441

tests/misc/nimcachetest/fun1.h

@@ -0,0 +1,2 @@
+// we include a file that gets modified in the test before the 1st and 2nd compilation
+#include "D20190123T230907.h"

tests/misc/nimcachetest/fun2.c

@@ -0,0 +1,6 @@
+#include "fun1.h"
+
+int foo(){
+  int a = MYVAR;
+  return a;
+}

tests/misc/nimcachetest/fun2.h

@@ -0,0 +1,3 @@
+#include <stdio.h>
+
+int foo();

tests/misc/nimcachetest/tmain.nim

@@ -0,0 +1,36 @@
+discard """
+disabled: true
+"""
+
+# issue #10441
+
+when defined(case_D20190123T230907): # child process
+  {.compile: ("fun2.c").}
+  proc foo(): cint {.importc, header:"fun1.h".}
+  echo foo()
+else:
+  # main process
+  import os, osproc, strformat, strutils
+  import compiler/unittest_light
+  import stdtest/specialpaths
+
+  proc main() =
+    const nim = getCurrentCompilerExe()
+    const input = currentSourcePath()
+    const headerGen = buildDir / "D20190123T230907.h"
+    defer: removeFile headerGen
+    #[
+    * the command line doesn't change across 2 subsequent invocations
+    * we pass --forceBuild:off just to make sure it's not overridden in config file
+    * the only thing that changes across the 2 `nim` invocations is  `headerGen`, included by `fun2.c`
+    ]#
+    let cmd = fmt"{nim} c --forceBuild:off -r --passC:-I{buildDir.quoteShell} -d:case_D20190123T230907 {input}"
+    for a in [123, 124]:
+      writeFile headerGen, fmt"""
+#define MYVAR {a}
+"""
+      var (output, exitCode) = execCmdEx(cmd, options = {})
+      doAssert exitCode == 0
+      output.stripLineEnd
+      assertEquals output, $a
+  main()