cache.config: Exact `url=` rules are dropped after successful parsing

[icpd]

Description

cache.config accepts url= as a primary destination. A valid rule passes parsing, but UrlMatcher does not add it to the URL hash table. The configuration loads without an error, and the rule never matches a request.

The insertion code is in UrlMatcher<Data, Result>::NewEntry() in src/proxy/ControlMatcher.cc:

cur_d = data_array + num_el;
error = cur_d->Init(line_info);

if (error.failed()) {
  url_str[num_el]   = ats_strdup(pattern);
  url_value[num_el] = num_el;
  url_ht.emplace(url_str[num_el], url_value[num_el]);
  num_el++;
}

return error;

error.failed() is true when initialization fails. This condition is backwards: a successfully initialized rule skips the insertion into url_ht, while the function still returns success.

Expected behavior

When cur_d->Init(line_info) succeeds, ATS should add the rule to url_ht. The rule's cache action should apply when a request URL exactly matches the configured value.

Cause

The exact URL matcher was added for TS-1280. The original code used a string pointer for errors and inserted the rule only after successful initialization:

errBuf = cur_d->Init(line_info);

if (errBuf == NULL) {
  // Insert into url_ht.
}

Commit 70cc2d4ce1762b182dd52f43a6313c61772c3a8a replaced the error string with config_parse_error. That type evaluates to true when an error is present, but the same change made the UrlMatcher condition if (error), reversing the old success check.

Commit 39f8e5c057386bffd51f5ba2284d2e715543e100 later changed the condition to if (error.failed()) without correcting the reversed logic.

Related commits:

• [Original implementation](2d9ad48)
• [Commit that introduced the regression](70cc2d4)
• Conversion to Result

Suggested fix

 error = cur_d->Init(line_info);

-if (error.failed()) {
+if (!error.failed()) {
   url_str[num_el]   = ats_strdup(pattern);
   url_value[num_el] = num_el;
   url_ht.emplace(url_str[num_el], url_value[num_el]);
   num_el++;
 }

Regression tests should cover:

• A valid url= rule is inserted and matches the complete URL.
• A different URL does not match the rule.
• A failed Init() call does not insert a rule and returns a configuration error.
• A duplicate url= value still returns the duplicate-rule error.