* Don't show trace information by default (`--show-trace' to enable).

NixOS evaluation errors in particular look intimidating and
  generally aren't very useful.  Ideally the builtins.throw messages
  should be self-contained.
This commit is contained in:
Eelco Dolstra 2009-06-30 13:28:29 +00:00
parent a2fc3a53ba
commit f2c3fc5191
6 changed files with 21 additions and 3 deletions

View file

@ -24,6 +24,7 @@
<arg><option>--fallback</option></arg>
<arg><option>--readonly-mode</option></arg>
<arg><option>--log-type</option> <replaceable>type</replaceable></arg>
<arg><option>--show-trace</option></arg>
<sbr />
</nop>

View file

@ -305,6 +305,14 @@
</varlistentry>
<varlistentry><term><option>--show-trace</option></term>
<listitem><para>Causes Nix to print out a stack trace in case of Nix
expression evaluation errors.</para></listitem>
</varlistentry>
</variablelist>

View file

@ -206,7 +206,7 @@ static Expr prim_abort(EvalState & state, const ATermVector & args)
static Expr prim_throw(EvalState & state, const ATermVector & args)
{
PathSet context;
throw ThrownError(format("user-thrown exception: `%1%'") %
throw ThrownError(format("user-thrown exception: %1%") %
evalString(state, args[0], context));
}

View file

@ -125,6 +125,9 @@ RemoveTempRoots::~RemoveTempRoots()
}
static bool showTrace = false;
/* Initialize and reorder arguments, then call the actual argument
processor. */
static void initAndRun(int argc, char * * argv)
@ -243,6 +246,8 @@ static void initAndRun(int argc, char * * argv)
maxSilentTime = getIntArg(arg, i, args.end());
else if (arg == "--no-build-hook")
useBuildHook = false;
else if (arg == "--show-trace")
showTrace = true;
else if (arg == "--option") {
++i; if (i == args.end()) throw UsageError("`--option' requires two arguments");
string name = *i;
@ -365,7 +370,9 @@ int main(int argc, char * * argv)
% e.what() % programId);
return 1;
} catch (BaseError & e) {
printMsg(lvlError, format("error: %1%") % e.msg());
printMsg(lvlError, format("error: %1%%2%") % (showTrace ? e.prefix() : "") % e.msg());
if (e.prefix() != "" && !showTrace)
printMsg(lvlError, "(use `--show-trace' to show detailed location information)");
return 1;
} catch (std::exception & e) {
printMsg(lvlError, format("error: %1%") % e.what());

View file

@ -24,12 +24,14 @@ using boost::format;
class BaseError : public std::exception
{
protected:
string prefix_; // used for location traces etc.
string err;
public:
BaseError(const format & f);
~BaseError() throw () { };
const char * what() const throw () { return err.c_str(); }
const string & msg() const throw () { return err; }
const string & prefix() const throw () { return prefix_; }
BaseError & addPrefix(const format & f);
};

View file

@ -33,7 +33,7 @@ BaseError::BaseError(const format & f)
BaseError & BaseError::addPrefix(const format & f)
{
err = f.str() + err;
prefix_ = f.str() + prefix_;
return *this;
}