From ed71173841618bd4c69f40d07fb467ccabc5db0b Mon Sep 17 00:00:00 2001 From: Jacob Abel Date: Sat, 9 Jul 2022 20:12:31 -0400 Subject: [PATCH] lib/strings: Update docs and restructured code to improve readability of toInt and toIntBase10. --- lib/strings.nix | 58 ++++++++++++++++++++++++++++---------------- lib/tests/misc.nix | 4 +++ lib/tests/modules.sh | 2 +- 3 files changed, 42 insertions(+), 22 deletions(-) diff --git a/lib/strings.nix b/lib/strings.nix index 5c5507b597b6..298d3b2af083 100644 --- a/lib/strings.nix +++ b/lib/strings.nix @@ -784,7 +784,7 @@ rec { false; /* Parse a string as an int. Does not support parsing of integers with preceding zero due to - ambiguity between zero-padded and octal numbers. + ambiguity between zero-padded and octal numbers. See toIntBase10. Type: string -> int @@ -805,25 +805,35 @@ rec { toInt "3.14" => error: floating point JSON numbers are not supported */ - # Obviously, it is a bit hacky to use fromJSON this way. toInt = str: let # RegEx: Match any leading whitespace, then any digits, and finally match any trailing # whitespace. strippedInput = match "[[:space:]]*([[:digit:]]+)[[:space:]]*" str; - # RegEx: Match any leading whitespace, then a leading '0', then at least one digit following - # after, and finally match any trailing whitespace. - isLeadingZero = match "[[:space:]]*0[[:digit:]]+[[:space:]]*" str == []; + # RegEx: Match a leading '0' then one or more digits. + isLeadingZero = match "0[[:digit:]]+" (head strippedInput) == []; # Attempt to parse input - parsedInput = fromJSON (elemAt strippedInput 0); + parsedInput = fromJSON (head strippedInput); + + generalError = "toInt: Could not convert ${escapeNixString str} to int."; + + octalAmbigError = "toInt: Ambiguity in interpretation of ${escapeNixString str}" + + " between octal and zero padded integer."; + in - if isLeadingZero - then throw "Ambiguity in interpretation of ${str} between octal and zero padded integer." - else if strippedInput != null && isInt parsedInput - then parsedInput - else throw "Could not convert ${str} to int."; + # Error on presence of non digit characters. + if strippedInput == null + then throw generalError + # Error on presence of leading zero/octal ambiguity. + else if isLeadingZero + then throw octalAmbigError + # Error if parse function fails. + else if !isInt parsedInput + then throw generalError + # Return result. + else parsedInput; /* Parse a string as a base 10 int. This supports parsing of zero-padded integers. @@ -846,26 +856,32 @@ rec { toIntBase10 "3.14" => error: floating point JSON numbers are not supported */ - # Obviously, it is a bit hacky to use fromJSON this way. toIntBase10 = str: let # RegEx: Match any leading whitespace, then match any zero padding, capture any remaining # digits after that, and finally match any trailing whitespace. strippedInput = match "[[:space:]]*0*([[:digit:]]+)[[:space:]]*" str; - # RegEx: Match any leading whitespace, at least one '0', and any trailing whitespace. - isZero = match "[[:space:]]*0+[[:space:]]*" str == []; + # RegEx: Match at least one '0'. + isZero = match "0+" (head strippedInput) == []; # Attempt to parse input - parsedInput = fromJSON (elemAt strippedInput 0); + parsedInput = fromJSON (head strippedInput); + + generalError = "toIntBase10: Could not convert ${escapeNixString str} to int."; + in - # Value is zero - if isZero + # Error on presence of non digit characters. + if strippedInput == null + then throw generalError + # In the special case zero-padded zero (00000), return early. + else if isZero then 0 - else - if strippedInput != null && isInt parsedInput - then parsedInput - else throw "Could not convert ${str} to int."; + # Error if parse function fails. + else if !isInt parsedInput + then throw generalError + # Return result. + else parsedInput; /* Read a list of paths from `file`, relative to the `rootPath`. Lines beginning with `#` are treated as comments and ignored. diff --git a/lib/tests/misc.nix b/lib/tests/misc.nix index 4bfc8bb87699..31c938a8ffda 100644 --- a/lib/tests/misc.nix +++ b/lib/tests/misc.nix @@ -346,6 +346,8 @@ runTests { ( builtins.tryEval (toInt "123 123") == { success = false; value = false; } ) ( builtins.tryEval (toInt "0 123") == { success = false; value = false; } ) ( builtins.tryEval (toInt " 0d ") == { success = false; value = false; } ) + ( builtins.tryEval (toInt " 1d ") == { success = false; value = false; } ) + ( builtins.tryEval (toInt " d0 ") == { success = false; value = false; } ) ( builtins.tryEval (toInt "00") == { success = false; value = false; } ) ( builtins.tryEval (toInt "01") == { success = false; value = false; } ) ( builtins.tryEval (toInt "002") == { success = false; value = false; } ) @@ -388,6 +390,8 @@ runTests { ( builtins.tryEval (toIntBase10 "123 123") == { success = false; value = false; } ) ( builtins.tryEval (toIntBase10 "0 123") == { success = false; value = false; } ) ( builtins.tryEval (toIntBase10 " 0d ") == { success = false; value = false; } ) + ( builtins.tryEval (toIntBase10 " 1d ") == { success = false; value = false; } ) + ( builtins.tryEval (toIntBase10 " d0 ") == { success = false; value = false; } ) ( builtins.tryEval (toIntBase10 " foo ") == { success = false; value = false; } ) ( builtins.tryEval (toIntBase10 " foo 123 ") == { success = false; value = false; } ) ( builtins.tryEval (toIntBase10 " foo 00123 ") == { success = false; value = false; } ) diff --git a/lib/tests/modules.sh b/lib/tests/modules.sh index 92c28369ed5c..c9ea674ee104 100755 --- a/lib/tests/modules.sh +++ b/lib/tests/modules.sh @@ -162,7 +162,7 @@ checkConfigError 'A definition for option .* is not.*string or signed integer co # Check coerced value with unsound coercion checkConfigOutput '^12$' config.value ./declare-coerced-value-unsound.nix checkConfigError 'A definition for option .* is not of type .*. Definition values:\n\s*- In .*: "1000"' config.value ./declare-coerced-value-unsound.nix ./define-value-string-bigint.nix -checkConfigError 'Could not convert .* to int' config.value ./declare-coerced-value-unsound.nix ./define-value-string-arbitrary.nix +checkConfigError 'toInt: Could not convert .* to int' config.value ./declare-coerced-value-unsound.nix ./define-value-string-arbitrary.nix # Check mkAliasOptionModule. checkConfigOutput '^true$' config.enable ./alias-with-priority.nix