Updated CHANGES/RELEASE to be a bit simpler. Fixed typo in docs for SHELL_ENV_GENERATORS.

5 files changed, 25 insertions, 13 deletions

diff --git a/CHANGES.txt b/CHANGES.txt
index d5aba9f..84ec06b 100755
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -99,9 +99,12 @@ RELEASE  VERSION/DATE TO BE FILLED IN LATER
     - Added user configurable setting of ninja depfile format via NINJA_DEPFILE_PARSE_FORMAT.
       Now setting NINJA_DEPFILE_PARSE_FORMAT to [msvc,gcc,clang] can force the ninja expected
       format. Compiler tools will also configure the variable automatically.
-    - Added SHELL_ENV_GENERATORS construction variable. This variable 
-      is an iterable which will contain functions in which each are called and each can allow
-      the user a method to customize the execution environment.
+    - Added SHELL_ENV_GENERATORS construction variable. This variable should be set to a list
+      (or an iterable) which contains functions to be called in order
+      when constructing the execution environment (Generally this is the shell environment
+      variables). This allows the user to customize how (for example) PATH is constructed.
+      Note that these are called for every build command run by SCons. It could have considerable
+      performance impact if not used carefully.
     - Updated ninja scons daemon scripts to output errors to stderr as well as the daemon log.
     - Fix typo in ninja scons daemon startup which causes ConnectionRefusedError to not retry 
       to connect to the server during start up.
diff --git a/RELEASE.txt b/RELEASE.txt
index 195e325..e7fa31c 100755
--- a/RELEASE.txt
+++ b/RELEASE.txt
@@ -16,9 +16,12 @@ NEW FUNCTIONALITY
 
 - Added MSVC_USE_SCRIPT_ARGS variable to pass arguments to MSVC_USE_SCRIPT.
 - Added Configure.CheckMember() checker to check if struct/class has the specified member.
-- Added SHELL_ENV_GENERATORS construction variable. This variable 
-  is an iterable which will contain functions in which each are called and each can allow
-  the user a method to customize the execution environment.
+- Added SHELL_ENV_GENERATORS construction variable. This variable should be set to a list
+  (or an iterable) which contains functions to be called in order
+  when constructing the execution environment (Generally this is the shell environment
+  variables). This allows the user to customize how (for example) PATH is constructed.
+  Note that these are called for every build command run by SCons. It could have considerable
+  performance impact if not used carefully.
 - Added MSVC_USE_SETTINGS variable to pass a dictionary to configure the msvc compiler
   system environment as an alternative to bypassing Visual Studio autodetection entirely.
 
diff --git a/SCons/Action.py b/SCons/Action.py
index e29c4e9..6e67c7f 100644
--- a/SCons/Action.py
+++ b/SCons/Action.py
@@ -756,9 +756,15 @@ def get_default_ENV(env):
 
 
 def _resolve_shell_env(env, target, source):
+    """
+    First get default environment.
+    Then if SHELL_ENV_GENERATORS is set and is iterable,
+    call each callable in that list to allow it to alter
+    the created execution environment.
+    """
     ENV = get_default_ENV(env)
-    shell_gen = env.get('SHELL_ENV_GENERATORS') 
-    if shell_gen is not None:
+    shell_gen = env.get('SHELL_ENV_GENERATORS')
+    if shell_gen:
         try:
             shell_gens = iter(shell_gen)
         except TypeError:
diff --git a/SCons/Action.xml b/SCons/Action.xml
index 8994adb..1346db2 100644
--- a/SCons/Action.xml
+++ b/SCons/Action.xml
@@ -203,7 +203,7 @@ in which the command should be executed.
 <cvar name="SHELL_ENV_GENERATORS">
   <summary>
     <para>
-Must be an iterable containing functions where each function generates or 
+Must be a list (or an iterable) containing functions where each function generates or
 alters the environment dictionary which will be used
 when executing the &cv-link-SPAWN; function. The functions will initially 
 be passed a reference of the current execution environment (e.g. env['ENV']), 
@@ -214,14 +214,14 @@ values.
 
 This primary purpose of this construction variable is to give the user the ability
 to substitute execution environment variables based on env, targets, and sources. 
-If desired, the user can completly customize the execution environment for particular 
+If desired, the user can completely customize the execution environment for particular
 targets.
     </para>
 
     <example_commands>
 def custom_shell_env(env, target, source, shell_env):
-    # customize shell_env if desired
-    if str(target[0]) == 'special_target'is:
+    """customize shell_env if desired"""
+    if str(target[0]) == 'special_target':
       shell_env['SPECIAL_VAR'] = env.subst('SOME_VAR', target=target, source=source)
     return shell_env
   
diff --git a/test/Actions/subst_shell_env.py b/test/Actions/subst_shell_env.py
index d26f0ae..02ba640 100644
--- a/test/Actions/subst_shell_env.py
+++ b/test/Actions/subst_shell_env.py
@@ -25,7 +25,7 @@
 
 """
 Verify that shell environment variables can be expanded per target/source
-when exectuting actions on the command line.
+when executing actions on the command line.
 """
 import os