syntax: strict string escapes #265
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jayconrod
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Mar 26, 2020
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Implementation and spec change look good. Makes sense if Python's doing the same thing.
Please link other issues related to this change in the commit message. I think they are bazelbuild/bazel#8380, bazelbuild/starlark#38, and maybe bazelbuild/buildtools#688.
doc/spec.md
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| \n \x0A line feed | ||
| \r \x0D carriage return | ||
| \t \x09 horizontal tab | ||
| \v \X0B vertical tab |
doc/spec.md
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| "a\ | ||
| b" # "ab" | ||
| r"a\ | ||
| b" # "a\\nb" |
doc/spec.md
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| ```python | ||
| "a\nb" # "a\nb" = 'a' + '\n' + 'b' | ||
| r"a\nb" # "a\\nb" = 'a' + '\' + '\n' + 'b' |
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alandonovan
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Mar 26, 2020
doc/spec.md
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| ```python | ||
| "a\nb" # "a\nb" = 'a' + '\n' + 'b' | ||
| r"a\nb" # "a\\nb" = 'a' + '\' + '\n' + 'b' |
doc/spec.md
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| \n \x0A line feed | ||
| \r \x0D carriage return | ||
| \t \x09 horizontal tab | ||
| \v \X0B vertical tab |
doc/spec.md
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| "a\ | ||
| b" # "ab" | ||
| r"a\ | ||
| b" # "a\\nb" |
This change causes Starlark, like Go, to reject backslashes that are not part of an escape sequence. Previously they were treated literally, so \ ( would encode a two-character string. Many programs rely on this, especially for regular expressions and shell commands, and will be broken by this change, but the fix is simple: double each errant backslash. Python does not yet enforce this behavior, but since 3.6 has emitted a deprecation warning for it. Also, document string escapes. Related issues: - Google issue b/34519173: "bazel: Forbid undefined escape sequences in strings" - bazelbuild/starlark#38: Starlark spec: String escapes - bazelbuild/buildtools#688: Bazel: Fix string escapes - bazelbuild/bazel#8380: Bazel incompatible_restrict_string_escapes: Restrict string escapes Change-Id: I5c9609a4e28d58593e9d6918757bca2cfd838d51
laurentlb
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Sep 24, 2020
Copied from google/starlark-go#265 I omitted the implementation notes.
laurentlb
added a commit
to bazelbuild/starlark
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Sep 25, 2020
Spec: document string literals Copied from google/starlark-go#265 I omitted the implementation notes and removed the note about the hex escape.
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This change causes Starlark, like Go, to reject backslashes that
are not part of an escape sequence. Previously they were treated
literally, so \ ( would encode a two-character string, and much
code relied on this, especially for regular expressions.
This may break some programs, but the fix is simple:
double each errant backslashes.
Python does not yet enforce this behavior, but since 3.6
has emitted a deprecation warning for it.
Also, document string escapes.
This is Google issue b/34519173.
Change-Id: I5c9609a4e28d58593e9d6918757bca2cfd838d51