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Fix false negatives in "break;" lint check

Summary: See D3449, comments, unit tests.

Test Plan: Unit tests.

Reviewers: vrana

Reviewed By: vrana

CC: aran

Differential Revision: https://secure.phabricator.com/D3463
This commit is contained in:
epriestley 2012-09-07 17:46:35 -07:00
parent 339cabedcc
commit 918eff8ff9
2 changed files with 86 additions and 14 deletions

View file

@ -487,28 +487,61 @@ final class ArcanistXHPASTLinter extends ArcanistLinter {
foreach ($blocks as $key => $block) {
$tokens = $block->getTokens();
// Collect all the tokens in this block which aren't at top level.
// We want to ignore "break", and "continue" in these blocks.
$lower_level = $block->selectDescendantsOfType('n_WHILE');
$lower_level->add($block->selectDescendantsOfType('n_DO_WHILE'));
$lower_level->add($block->selectDescendantsOfType('n_FOR'));
$lower_level->add($block->selectDescendantsOfType('n_FOREACH'));
$lower_level->add($block->selectDescendantsOfType('n_SWITCH'));
$lower_level_tokens = array();
foreach ($lower_level as $lower_level_block) {
$lower_level_tokens += $lower_level_block->getTokens();
}
// Collect all the tokens in this block which aren't in this scope
// (because they're inside class, function or interface declarations).
// We want to ignore all of these tokens.
$decls = $block->selectDescendantsOfType('n_FUNCTION_DECLARATION');
$decls->add($block->selectDescendantsOfType('n_CLASS_DECLARATION'));
// For completeness; these can't actually have anything.
$decls->add($block->selectDescendantsOfType('n_INTERFACE_DECLARATION'));
$different_scope_tokens = array();
foreach ($decls as $decl) {
$different_scope_tokens += $decl->getTokens();
}
$lower_level_tokens += $different_scope_tokens;
// Get all the trailing nonsemantic tokens, since we need to look for
// "fallthrough" comments past the end of the semantic block.
$tokens = $block->getTokens();
$last = end($tokens);
while ($last && $last = $last->getNextToken()) {
if (!$last->isSemantic()) {
$tokens[] = $last;
$tokens[$last->getTokenID()] = $last;
}
}
$blocks[$key] = $tokens;
$blocks[$key] = array(
$tokens,
$lower_level_tokens,
$different_scope_tokens,
);
}
foreach ($blocks as $tokens) {
foreach ($blocks as $token_lists) {
list(
$tokens,
$lower_level_tokens,
$different_scope_tokens) = $token_lists;
// Test each block (case or default statement) to see if it's OK. It's
// OK if:
//
// - it is empty; or
// - it ends in break, return, throw, continue or exit; or
// - it ends in break, return, throw, continue or exit at top level; or
// - it has a comment with "fallthrough" in its text.
// Empty blocks are OK, so we start this at `true` and only set it to
@ -519,7 +552,7 @@ final class ArcanistXHPASTLinter extends ArcanistLinter {
// the block (break, return, throw, continue) or something else.
$statement_ok = false;
foreach ($tokens as $token) {
foreach ($tokens as $token_id => $token) {
if (!$token->isSemantic()) {
// Liberally match "fall" in the comment text so that comments like
// "fallthru", "fall through", "fallthrough", etc., are accepted.
@ -532,6 +565,14 @@ final class ArcanistXHPASTLinter extends ArcanistLinter {
$tok_type = $token->getTypeName();
if ($tok_type == 'T_FUNCTION' ||
$tok_type == 'T_CLASS' ||
$tok_type == 'T_INTERFACE') {
// These aren't statements, but mark the block as nonempty anyway.
$block_ok = false;
continue;
}
if ($tok_type == ';') {
if ($statement_ok) {
$statment_ok = false;
@ -541,13 +582,23 @@ final class ArcanistXHPASTLinter extends ArcanistLinter {
continue;
}
if ($tok_type == 'T_BREAK' ||
$tok_type == 'T_CONTINUE') {
if (empty($lower_level_tokens[$token_id])) {
$statement_ok = true;
$block_ok = true;
}
continue;
}
if ($tok_type == 'T_RETURN' ||
$tok_type == 'T_BREAK' ||
$tok_type == 'T_CONTINUE' ||
$tok_type == 'T_THROW' ||
$tok_type == 'T_EXIT') {
$statement_ok = true;
$block_ok = true;
if (empty($different_scope_tokens[$token_id])) {
$statement_ok = true;
$block_ok = true;
}
continue;
}
}

View file

@ -54,16 +54,37 @@ switch ($x) {
while (true) {
break;
}
// TODO: false negative
case 2:
switch ($y) {
case 1:
break;
}
// TODO: false negative
case 3:
while (true) {
return;
}
case 4:
function f() { throw new Exception(); }
g(function() { return; });
final class C { public function m() { return; } }
interface I { }
case 5:
do {
break;
} while (true);
case 6:
// We accept this "false" positive because the construction is bizarre and
// the author can easily add an unreachable "break;" for clarity.
do {
break 2;
} while (true);
}
~~~~~~~~~~
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