whence -v: fix path canonicalisation

This bug was mediated by the fact that path_search() prefixes the
present working directory to any relative path, but does not do any
other canonicalisation. A faulty check then caused that path to be
considered an absolute path and not in need of canonicalising, even
if it contained '.' and '..' elements or double slashes.

src/cmd/ksh93/bltins/whence.c:
- Remove faulty check for initial '/' that prevented
  path_fullname() from ever being called.

src/cmd/ksh93/tests/builtins.sh:
- Add two 'whence -v' path canonicalisation tests.
- Tweak other 'whence' tests for consistency.

Fixes #84

NEWS

@@ -8,6 +8,8 @@ Any uppercase BUG_* names are modernish shell bug IDs.
 - If a shell function and a built-in command by the same name exist,
   'whence -a' and 'type -a' now report both.
 
+- 'whence -v' now canonicalizes relative paths properly.
+
 - Fixed a bug that caused file descriptors opened with 'redirect' or 'exec'
   to survive a subshell environment after exiting it.
 

src/cmd/ksh93/bltins/whence.c

@@ -231,7 +231,7 @@ static int whence(Shell_t *shp,char **argv, register int flags)
 				cp = stakptr(PATH_OFFSET);
 				if(*cp==0)
 					cp = 0;
-				else if(*cp!='/')
+				else
 				{
 					cp = path_fullname(shp,cp);
 					tofree=1;

src/cmd/ksh93/tests/builtins.sh

@@ -732,42 +732,56 @@ foo=BUG command eval ':'
 [[ $foo == BUG ]] && err_exit '`command` fails to disable the special properties of special builtins'
 
 # ======
-# 'whence -a' tests
+# whence -a/-v tests
 
 # wrong path to tracked aliases after loading builtin: https://github.com/ksh93/ksh/pull/25
 actual=$("$SHELL" -c '
 	whence chmod >/dev/null  # add to hash table (create tracked alias)
 	builtin chmod
 	whence -a chmod
 ')
-expected="chmod is a shell builtin
+expect="chmod is a shell builtin
 $(whence -a -p chmod | sed 's/^/chmod is /')
 chmod is a tracked alias for $(whence -p chmod)"
-[[ $actual == $expected ]] || err_exit "'whence -a' does not work correctly with tracked aliases" \
-	"(expected $(printf %q "$expected"), got $(printf %q "$actual"))"
+[[ $actual == $expect ]] || err_exit "'whence -a' does not work correctly with tracked aliases" \
+	"(expected $(printf %q "$expect"), got $(printf %q "$actual"))"
 
 # spurious 'undefined function' message: https://github.com/ksh93/ksh/issues/26
 actual=$("$SHELL" -c 'whence -a printf')
-expected="printf is a shell builtin
+expect="printf is a shell builtin
 $(whence -a -p printf | sed 's/^/printf is /')"
-[[ $actual == $expected ]] || err_exit "'whence -a': incorrect output" \
-	"(expected $(printf %q "$expected"), got $(printf %q "$actual"))"
+[[ $actual == $expect ]] || err_exit "'whence -a': incorrect output" \
+	"(expected $(printf %q "$expect"), got $(printf %q "$actual"))"
 
 # 'whence -a'/'type -a' failed to list builtin if function exists: https://github.com/ksh93/ksh/issues/83
 actual=$(printf() { :; }; whence -a printf)
-expected="printf is a function
+expect="printf is a function
 printf is a shell builtin
 $(whence -a -p printf | sed 's/^/printf is /')"
-[[ $actual == $expected ]] || err_exit "'whence -a': incorrect output for function+builtin" \
-        "(expected $(printf %q "$expected"), got $(printf %q "$actual"))"
-
-# 'whence -a'/'type -a' failed to list builtin if autoload function exists: https://github.com/ksh93/ksh/issues/83
+[[ $actual == $expect ]] || err_exit "'whence -a': incorrect output for function+builtin" \
+        "(expected $(printf %q "$expect"), got $(printf %q "$actual"))"
 actual=$(autoload printf; whence -a printf)
-expected="printf is an undefined function
+expect="printf is an undefined function
 printf is a shell builtin
 $(whence -a -p printf | sed 's/^/printf is /')"
-[[ $actual == $expected ]] || err_exit "'whence -a': incorrect output for autoload+builtin" \
-        "(expected $(printf %q "$expected"), got $(printf %q "$actual"))"
+[[ $actual == $expect ]] || err_exit "'whence -a': incorrect output for autoload+builtin" \
+        "(expected $(printf %q "$expect"), got $(printf %q "$actual"))"
+
+# 'whence -v' canonicalized paths improperly: https://github.com/ksh93/ksh/issues/84
+cmdpath=${ whence -p printf; }
+actual=$(cd /; whence -v "${cmdpath#/}")
+expect="${cmdpath#/} is $cmdpath"
+[[ $actual == $expect ]] || err_exit "'whence -v': incorrect canonicalization of initial /" \
+        "(expected $(printf %q "$expect"), got $(printf %q "$actual"))"
+dotdot=
+num=$(set -f; IFS=/; set -- $PWD; echo $#)
+for ((i=1; i<num; i++))
+do	dotdot+='../'
+done
+actual=$(cd /; whence -v "$dotdot${cmdpath#/}")
+expect="$dotdot${cmdpath#/} is $cmdpath"
+[[ $actual == $expect ]] || err_exit "'whence -v': incorrect canonicalization of pathname containing '..'" \
+        "(expected $(printf %q "$expect"), got $(printf %q "$actual"))"
 
 # ======
 # 'cd ../.foo' should not exclude the '.' in '.foo'