TeamCity File Content Replacer : string index out of range

Question

I am trying to use TeamCity File Content Replacer build feature to replace certain keys in my App.config file (.NET console project). As mentioned in official documentation i have specified

Process File : File which i would like to make replacements in
Find what : RegEx which denotes the text i would like to replace
Replace With : TeamCity variable with which i like to replace text

Everything works fine if Replace With text is short enough , for example dummyText works however things go wrong with lengthier values like \\Server675X\Shared\Artifactory\ , the error message received in build logs is as follows :

[File Content Replacer] Applying replacement "\\Server675X\Shared\Artifactory\" to lines matched by pattern "(?<=key="MappingFileLocation" value=").*(?="\/>)" in the files matched by wildcard: **/SolutionName/App.config...

[File Content Replacer] Error replacing "(?<=key="MappingFileLocation" value=").*(?="\/>)" with "\\Server675X\Shared\Artifactory\": string index out of range: 32. Check your settings.

[File Content Replacer] Error replacing file contents: string index out of range: 32

I can see that 32 is exactly the length of replacement string, question is what setting do i need to check/modify to make this replacement possible ?

PS : I am using TeamCity Enterprise 9.1.7 (build 37573)

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Answer 1

Finally found the solution to the problem, the error message is very misleading the actual problem lies in escaping backslash

using \\Server675X\Shared\Artifactory\ gives an error

Error replacing file contents: string index out of range: 32

however when we use \\\\Server675X\\Shared\\Artifactory\\ there is no error, notice how we escaped backslash.

It would have been better to receive a relevant error message saying un-escaped character found or something along these lines.

Hope this helps someone !