From: Daniel Shahaf <d.s@daniel.shahaf.name>
To: zsh-workers@zsh.org
Subject: [PATCH] Make the parameter expansion subscript flags parse error message, "error in flags", identify the location of the parse error.
Date: Sat, 3 Apr 2021 02:49:54 +0000 [thread overview]
Message-ID: <20210403024954.4321-1-danielsh@tarpaulin.shahaf.local2> (raw)
---
Review of the logic obtaining and massaging str_copy_for_output would be
appreciated. It's a 2500-line function and there are multiple char*
variables that refer to the same memory locations as *str, so it's
conceivable I overlooked something.
If it's too brittle, an alternative is to simply output «s» untokenized.
In the test case, that would output «x+):-}».
The offset is computed 1-based even when KSH_ARRAYS is set. I don't
think interpretation of an error message should depend on the option
settings current at the time of the error message.
Cheers,
Daniel
Src/subst.c | 28 +++++++++++++++++++++++++---
Test/D04parameter.ztst | 5 +++++
2 files changed, 30 insertions(+), 3 deletions(-)
diff --git a/Src/subst.c b/Src/subst.c
index 8f5bd355e..96e0914eb 100644
--- a/Src/subst.c
+++ b/Src/subst.c
@@ -2259,9 +2259,31 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int pf_flags,
break;
default:
- flagerr:
- zerr("error in flags");
- return NULL;
+ flagerr:
+ {
+ /*
+ * We're trying to output the string that failed to
+ * parse and the offset of the parse error within that.
+ *
+ * The string is *str. It hasn't been changed since
+ * entry to this function, I think, except that the
+ * first non-variable-declaration line in this function
+ * (currently the 238th line in this function)
+ * writes a NUL to the first place in *str, so we'll
+ * compensate by outputting the dollar sign manually.
+ */
+ char *str_copy_for_output = dupstring(*str + 1);
+
+ /*
+ * Convert to a 1-based offset, because the shell
+ * language is 1-based by default.
+ */
+ zlong offset = s - *str + 1;
+
+ untokenize(str_copy_for_output);
+ zerr("error in flags near position %z in '$%s'", offset, str_copy_for_output);
+ return NULL;
+ }
}
}
s++;
diff --git a/Test/D04parameter.ztst b/Test/D04parameter.ztst
index ac99ff0e3..05bb61bdc 100644
--- a/Test/D04parameter.ztst
+++ b/Test/D04parameter.ztst
@@ -2691,3 +2691,8 @@ F:behavior, see http://austingroupbugs.net/view.php?id=888
eval 'echo $(\*)'
0:Backslash character other than newline is normal after $(
>What a star
+
+ : ${(zZ+x+):-}
+1:parameter expansion flags parsing error gives a clue
+?(eval):1: error in flags near position 7 in '${(zZ+x+):-}'
+
next reply other threads:[~2021-04-03 2:50 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-03 2:49 Daniel Shahaf [this message]
2021-04-04 16:27 ` Peter Stephenson
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