From 7dcae31c1eaa45626718a2cef5984b200ba59af0 Mon Sep 17 00:00:00 2001
From: Joseph Brill <48932340+jcbrill@users.noreply.github.com>
Date: Sun, 15 May 2022 11:56:22 -0400
Subject: Change cache key to tuple and read/write list of dictionaries to json

---
 SCons/Tool/MSCommon/common.py | 6 ++++--
 SCons/Tool/MSCommon/vc.py     | 2 +-
 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/SCons/Tool/MSCommon/common.py b/SCons/Tool/MSCommon/common.py
index bc7cad3..591359d 100644
--- a/SCons/Tool/MSCommon/common.py
+++ b/SCons/Tool/MSCommon/common.py
@@ -106,7 +106,8 @@ def read_script_env_cache():
         try:
             p = Path(CONFIG_CACHE)
             with p.open('r') as f:
-                envcache = json.load(f)
+                envcache_list = json.load(f)
+                envcache = {tuple(d['key']): d['data'] for d in envcache_list}
         except FileNotFoundError:
             # don't fail if no cache file, just proceed without it
             pass
@@ -119,7 +120,8 @@ def write_script_env_cache(cache):
         try:
             p = Path(CONFIG_CACHE)
             with p.open('w') as f:
-                json.dump(cache, f, indent=2)
+                envcache_list = [{'key': list(key), 'data': data} for key, data in cache.items()]
+                json.dump(envcache_list, f, indent=2)
         except TypeError:
             # data can't serialize to json, don't leave partial file
             with suppress(FileNotFoundError):
diff --git a/SCons/Tool/MSCommon/vc.py b/SCons/Tool/MSCommon/vc.py
index 525051c..7f758f5 100644
--- a/SCons/Tool/MSCommon/vc.py
+++ b/SCons/Tool/MSCommon/vc.py
@@ -986,7 +986,7 @@ def script_env(script, args=None):
 
     if script_env_cache is None:
         script_env_cache = common.read_script_env_cache()
-    cache_key = f"{script}--{args}" if args else f"{script}"
+    cache_key = (script, args if args else None)
     cache_data = script_env_cache.get(cache_key, None)
 
     # Brief sanity check: if we got a value for the key,
-- 
cgit v0.12


From e7e365ed20be7e7a2e0a079ca47a33416d725eca Mon Sep 17 00:00:00 2001
From: Joseph Brill <48932340+jcbrill@users.noreply.github.com>
Date: Sun, 15 May 2022 14:24:42 -0400
Subject: Add comments describing reason for data structure conversion to/from
 json

---
 SCons/Tool/MSCommon/common.py | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/SCons/Tool/MSCommon/common.py b/SCons/Tool/MSCommon/common.py
index 591359d..e009fd5 100644
--- a/SCons/Tool/MSCommon/common.py
+++ b/SCons/Tool/MSCommon/common.py
@@ -106,6 +106,9 @@ def read_script_env_cache():
         try:
             p = Path(CONFIG_CACHE)
             with p.open('r') as f:
+                # Convert the list of cache entry dictionaries read from
+                # json to the cache dictionary. Reconstruct the cache key
+                # tuple from the key list written to json.
                 envcache_list = json.load(f)
                 envcache = {tuple(d['key']): d['data'] for d in envcache_list}
         except FileNotFoundError:
@@ -120,6 +123,9 @@ def write_script_env_cache(cache):
         try:
             p = Path(CONFIG_CACHE)
             with p.open('w') as f:
+                # Convert the cache dictionary to a list of cache entry
+                # dictionaries. The cache key is converted from a tuple to
+                # a list for compatibility with json.
                 envcache_list = [{'key': list(key), 'data': data} for key, data in cache.items()]
                 json.dump(envcache_list, f, indent=2)
         except TypeError:
-- 
cgit v0.12