BLD, BUG: Fix bdist_wheel duplicate building

  The bug can occur only if the build option `build`
  was passed before the option `bdist_wheel`.

  You may still realize a duplicate printing for the compiler
  optimization report in the build log, which is normal due to
  multiple calling of command `build` by setuptools.

3 files changed, 54 insertions, 26 deletions

diff --git a/numpy/distutils/ccompiler_opt.py b/numpy/distutils/ccompiler_opt.py
index aea9835c7..316d3a338 100644
--- a/numpy/distutils/ccompiler_opt.py
+++ b/numpy/distutils/ccompiler_opt.py
@@ -747,12 +747,14 @@ class _Cache:
         self.cache_me = {}
         self.cache_private = set()
         self.cache_infile = False
+        self._cache_path = None
 
         if self.conf_nocache:
             self.dist_log("cache is disabled by `Config`")
             return
 
-        chash = self.cache_hash(*factors, *self.conf_cache_factors)
+        self._cache_hash = self.cache_hash(*factors, *self.conf_cache_factors)
+        self._cache_path = cache_path
         if cache_path:
             if os.path.exists(cache_path):
                 self.dist_log("load cache from file ->", cache_path)
@@ -765,7 +767,7 @@ class _Cache:
                 elif not hasattr(cache_mod, "hash") or \
                      not hasattr(cache_mod, "data"):
                     self.dist_log("invalid cache file", stderr=True)
-                elif chash == cache_mod.hash:
+                elif self._cache_hash == cache_mod.hash:
                     self.dist_log("hit the file cache")
                     for attr, val in cache_mod.data.items():
                         setattr(self, attr, val)
@@ -773,10 +775,8 @@ class _Cache:
                 else:
                     self.dist_log("miss the file cache")
 
-            atexit.register(self._cache_write, cache_path, chash)
-
         if not self.cache_infile:
-            other_cache = _share_cache.get(chash)
+            other_cache = _share_cache.get(self._cache_hash)
             if other_cache:
                 self.dist_log("hit the memory cache")
                 for attr, val in other_cache.__dict__.items():
@@ -785,32 +785,41 @@ class _Cache:
                         continue
                     setattr(self, attr, val)
 
-        _share_cache[chash] = self
+        _share_cache[self._cache_hash] = self
+        atexit.register(self.cache_flush)
 
     def __del__(self):
-        # TODO: remove the cache form share on del
-        pass
+        for h, o in _share_cache.items():
+            if o == self:
+                _share_cache.pop(h)
+                break
 
-    def _cache_write(self, cache_path, cache_hash):
+    def cache_flush(self):
+        """
+        Force update the cache.
+        """
+        if not self._cache_path:
+            return
         # TODO: don't write if the cache doesn't change
-        self.dist_log("write cache to path ->", cache_path)
-        for attr in list(self.__dict__.keys()):
+        self.dist_log("write cache to path ->", self._cache_path)
+        cdict = self.__dict__.copy()
+        for attr in self.__dict__.keys():
             if re.match(self._cache_ignore, attr):
-                self.__dict__.pop(attr)
+                cdict.pop(attr)
 
-        d = os.path.dirname(cache_path)
+        d = os.path.dirname(self._cache_path)
         if not os.path.exists(d):
             os.makedirs(d)
 
-        repr_dict = pprint.pformat(self.__dict__, compact=True)
-        with open(cache_path, "w") as f:
+        repr_dict = pprint.pformat(cdict, compact=True)
+        with open(self._cache_path, "w") as f:
             f.write(textwrap.dedent("""\
             # AUTOGENERATED DON'T EDIT
             # Please make changes to the code generator \
             (distutils/ccompiler_opt.py)
             hash = {}
             data = \\
-            """).format(cache_hash))
+            """).format(self._cache_hash))
             f.write(repr_dict)
 
     def cache_hash(self, *factors):
diff --git a/numpy/distutils/command/build_clib.py b/numpy/distutils/command/build_clib.py
index e1f15d465..0e31a7dee 100644
--- a/numpy/distutils/command/build_clib.py
+++ b/numpy/distutils/command/build_clib.py
@@ -123,15 +123,20 @@ class build_clib(old_build_clib):
             opt_cache_path = os.path.abspath(
                 os.path.join(self.build_temp, 'ccompiler_opt_cache_clib.py')
             )
+            if hasattr(self, "compiler_opt"):
+                # By default `CCompilerOpt` update the cache at the exit of
+                # the process, which may lead to duplicate building
+                # (see build_extension()/force_rebuild) if run() called
+                # multiple times within the same os process/thread without
+                # giving the chance the previous instances of `CCompilerOpt`
+                # to update the cache.
+                self.compiler_opt.cache_flush()
+
             self.compiler_opt = new_ccompiler_opt(
                 compiler=self.compiler, dispatch_hpath=dispatch_hpath,
                 cpu_baseline=self.cpu_baseline, cpu_dispatch=self.cpu_dispatch,
                 cache_path=opt_cache_path
             )
-            if not self.compiler_opt.is_cached():
-                log.info("Detected changes on compiler optimizations, force rebuilding")
-                self.force = True
-
             def report(copt):
                 log.info("\n########### CLIB COMPILER OPTIMIZATION ###########")
                 log.info(copt.report(full=True))
@@ -212,7 +217,12 @@ class build_clib(old_build_clib):
         lib_file = compiler.library_filename(lib_name,
                                              output_dir=self.build_clib)
         depends = sources + build_info.get('depends', [])
-        if not (self.force or newer_group(depends, lib_file, 'newer')):
+
+        force_rebuild = self.force
+        if not self.disable_optimization and not self.compiler_opt.is_cached():
+            log.debug("Detected changes on compiler optimizations")
+            force_rebuild = True
+        if not (force_rebuild or newer_group(depends, lib_file, 'newer')):
             log.debug("skipping '%s' library (up-to-date)", lib_name)
             return
         else:
diff --git a/numpy/distutils/command/build_ext.py b/numpy/distutils/command/build_ext.py
index ca29ad4c0..84ec8aa2c 100644
--- a/numpy/distutils/command/build_ext.py
+++ b/numpy/distutils/command/build_ext.py
@@ -151,15 +151,20 @@ class build_ext (old_build_ext):
             opt_cache_path = os.path.abspath(
                 os.path.join(self.build_temp, 'ccompiler_opt_cache_ext.py')
             )
+            if hasattr(self, "compiler_opt"):
+                # By default `CCompilerOpt` update the cache at the exit of
+                # the process, which may lead to duplicate building
+                # (see build_extension()/force_rebuild) if run() called
+                # multiple times within the same os process/thread without
+                # giving the chance the previous instances of `CCompilerOpt`
+                # to update the cache.
+                self.compiler_opt.cache_flush()
+
             self.compiler_opt = new_ccompiler_opt(
                 compiler=self.compiler, dispatch_hpath=dispatch_hpath,
                 cpu_baseline=self.cpu_baseline, cpu_dispatch=self.cpu_dispatch,
                 cache_path=opt_cache_path
             )
-            if not self.compiler_opt.is_cached():
-                log.info("Detected changes on compiler optimizations, force rebuilding")
-                self.force = True
-
             def report(copt):
                 log.info("\n########### EXT COMPILER OPTIMIZATION ###########")
                 log.info(copt.report(full=True))
@@ -360,7 +365,11 @@ class build_ext (old_build_ext):
                                         self.get_ext_filename(fullname))
         depends = sources + ext.depends
 
-        if not (self.force or newer_group(depends, ext_filename, 'newer')):
+        force_rebuild = self.force
+        if not self.disable_optimization and not self.compiler_opt.is_cached():
+            log.debug("Detected changes on compiler optimizations")
+            force_rebuild = True
+        if not (force_rebuild or newer_group(depends, ext_filename, 'newer')):
             log.debug("skipping '%s' extension (up-to-date)", ext.name)
             return
         else: