Batch - Variable giving different outputs at ECHO and IF - windows

Question

I am currently implementing a postprocess in batch, and after some changes a few code snipplets simply don't work anymore....
What I am trying to do:
#echo off & setlocal
ECHO %netUse% //For debugging!
IF NOT "%netUse%" == "" ( //Double checking if Variable is set
IF %netUse% EQU 1 (
IF %netUsePW% EQU 1 (
NET USE %netUseLetter% %netPath% %pw% /user:%netUser%
)
IF %netUsePW% EQU 0 (
NET USE %netUseLetter% %netPath%
)
)
)
When I run that code, this is the output:
C:\Program Files (x86)\ID GmbH\PRODETTE\DAX\ISDN>ECHO 0
0 <--- That's right! It is set to ZERO via a "configuration" Batch
"1" kann syntaktisch an dieser Stelle nicht verarbeitet werden. <-- ???
C:\Program Files (x86)\ID GmbH\PRODETTE\DAX\ISDN> IF EQU 1 ( <-- Why isn't it comparing the variable?
And just for completionists sake, I am loading all of these variables form another batch file, "Settings.bat"
I am running that file via
CALL :postCopySettings.bat
contents:
SET netUse=0
SET netUsePW=
SET netUseLetter=
SET netPath=
SET netUser=
SET pw=
SET configLoaded=1
(Since netUse is 0, I don't need to populate the other variables... right?)
TL:DR: Batch doesn't work, but I don't know why.

Answer 1

The problem is that variable netUsePW is not set.
When netUse is set to 0, and netUsePW, netUseLetter, netUsePath, pw are all empty, your code...:
#echo off & setlocal
ECHO %netUse%
IF NOT "%netUse%" == "" (
IF %netUse% EQU 1 (
IF %netUsePW% EQU 1 (
NET USE %netUseLetter% %netPath% %pw% /user:%netUser%
)
IF %netUsePW% EQU 0 (
NET USE %netUseLetter% %netPath%
)
)
)
...expands to...:
#echo off & setlocal
ECHO 0
IF NOT "0" == "" (
IF 0 EQU 1 (
IF EQU 1 (
NET USE /user:0
)
IF EQU 0 (
NET USE
)
)
)
As you can see, there are two syntax issues, which cause the error:
IF EQU 1
IF EQU 0
Although netUse is set to 0 and you therefore expect the statements after IF %netUse% EQU 1 not to be executed, they are still parsed, because the entire code block is parsed before any commands are executed.
To overcome this, there are several ways:
Preset variables with non-empty values:
#echo off & setlocal
ECHO %netUse%
IF "%netUse%" == "" (set "netUse=-1" & set "setUsePW=-1")
IF NOT "%netUse%" == "" (
IF %netUse% EQU 1 (
IF %netUsePW% EQU 1 (
NET USE %netUseLetter% %netPath% %pw% /user:%netUser%
)
IF %netUsePW% EQU 0 (
NET USE %netUseLetter% %netPath%
)
)
)
Avoid code blocks by changing the logic a bit and using goto:
#echo off & setlocal
ECHO %netUse%
IF "%netUse%" == "" goto :SKIP
IF %netUse% NEQ 1 goto :SKIP
IF %netUsePW% EQU 1 (
NET USE %netUseLetter% %netPath% %pw% /user:%netUser%
)
IF %netUsePW% EQU 0 (
NET USE %netUseLetter% %netPath%
)
:SKIP
Avoid code blocks by moving some code into subroutines and using call to call them:
#echo off & setlocal
ECHO %netUse%
IF NOT "%netUse%" == "" call :TEST "%netUse%" "%netUsePW%" "%netUseLetter%" "%netPath%" "%pw%"
exit /B
:TEST
IF %~1 EQU 1 call :TESTPW "%~1" "%~2" "%~3" "%~4" "%~5"
exit /B
:TESTPW
IF %~2 EQU 1 (
NET USE %~3 %~4 %~5 /user:%~1
)
IF %~2 EQU 0 (
NET USE %~3 %~4
)
exit /B
Enable and apply delayed expansion to do the variable expansion during execution rather than while parsing:
#echo off & setlocal EnableDelayedExpansion
ECHO %netUse%
IF NOT "%netUse%" == "" (
IF !netUse! EQU 1 (
IF !netUsePW! EQU 1 (
NET USE %netUseLetter% %netPath% %pw% /user:!netUser!
)
IF !netUsePW! EQU 0 (
NET USE %netUseLetter% %netPath%
)
)
)

Answer 2

IF NOT "%netUse%" == "" ( //Double checking if Variable is set
IF %netUse% EQU 1 (
IF %netUsePW% EQU 1 (
No point in testing "netuse" then complaining that "netusePW" is not set.