quick fix

Author: p

lib/datadog/di/code_tracker.rb

@@ -140,16 +140,23 @@ def iseqs_for_path_suffix(suffix)
           exact = registry[suffix]
           return [suffix, exact] if exact
 
-          inexact = []
-          registry.each do |path, iseq|
-            if Utils.path_matches_suffix?(path, suffix)
-              inexact << [path, iseq]
+          suffix = suffix.dup
+          loop do
+            inexact = []
+            registry.each do |path, iseq|
+              if Utils.path_matches_suffix?(path, suffix)
+                inexact << [path, iseq]
+              end
             end
+            if inexact.length > 1
+              raise Error::MultiplePathsMatch, "Multiple paths matched requested suffix"
+            end
+            if inexact.any?
+              return inexact.first
+            end
+            return nil unless suffix.include?('/')
+            suffix.sub!(%r,.*/+,, '')
           end
-          if inexact.length > 1
-            raise Error::MultiplePathsMatch, "Multiple paths matched requested suffix"
-          end
-          inexact.first
         end
       end
 

lib/datadog/di/probe.rb

@@ -155,19 +155,16 @@ def location
       # Returns whether the provided +path+ matches the user-designated
       # file (of a line probe).
       #
-      # If file is an absolute path (i.e., it starts with a slash), the file
-      # must be identical to path to match.
-      #
-      # If file is not an absolute path, the path matches if the file is its suffix,
-      # at a path component boundary.
+      # Delegates to Utils.path_can_match_spec? which performs fuzzy
+      # matching. See the comments in utils.rb for details.
       def file_matches?(path)
         if path.nil?
           raise ArgumentError, "Cannot match against a nil path"
         end
         unless file
           raise ArgumentError, "Probe does not have a file to match against"
         end
-        Utils.path_matches_suffix?(path, file)
+        Utils.path_can_match_spec?(path, file)
       end
 
       # Instrumentation module for method probes.

lib/datadog/di/utils.rb

@@ -3,8 +3,8 @@
 module Datadog
   module DI
     module Utils
-      # Returns whether the provided +path+ matches the user-designated
-      # file suffix or path (of a line probe).
+      # General path matching considerations
+      # ------------------------------------
       #
       # The following use cases must be supported:
       # 1. The "probe path" is relative path to the file from source code
@@ -29,7 +29,7 @@ module Utils
       # specification in the probe, the tracer must return an error to the
       # backend/UI rather than instrumenting any of the matching paths.
       #
-      # The logic for path matching is therefore, generally, as follows:
+      # The logic for path matching should therefore, generally, be as follows:
       # 1. If the "probe path" is absolute, see if it exists at runtime.
       #    If so, take it as the desired path and finish.
       # 2. Attempt to identify the application root, by checking if the current
@@ -75,6 +75,12 @@ module Utils
       # indefinitely cache whether a particular filesystem paths exists
       # in both positive and negative.
       #
+      # As a "quick fix", currently after performing the suffix matching
+      # we just strip leading directory components from the "probe path"
+      # until we get a match via a "suffix of the suffix".
+
+      # Returns whether the provided +path+ matches the user-designated
+      # file suffix (of a line probe).
       #
       # If suffix is an absolute path (i.e., it starts with a slash), the path
       # must be identical for it to match.
@@ -111,6 +117,21 @@ module Utils
           # !!(path =~ %r,(/|\A)#{Regexp.quote(suffix)}\z,)
         end
       end
+
+      # Returns whether the provided +path+ matches the "probe path" in
+      # +spec+. Attempts all of the fuzzy matches by stripping directories
+      # from the front of +spec+. Does not consider othr known paths to
+      # identify the case of (potentially) multiple matching paths for +spec+.
+      module_function def path_can_match_spec?(path, spec)
+        return true if path_matches_suffix?(path, spec)
+
+        spec = spec.dup
+        loop do
+          return false unless spec.include?('/')
+          spec.sub!(%r,.*/+,, '')
+          return true if path_matches_suffix?(path, spec)
+        end
+      end
     end
   end
 end

spec/datadog/di/utils_spec.rb

@@ -5,6 +5,8 @@
   di_test
 
   describe '.path_matches_suffix?' do
+    # NB; when updating this list also add to the list in
+    # path_can_match_spec? test below.
     [
       ['exact match - absolute path', '/foo/bar.rb', '/foo/bar.rb', true],
       # Suffix matching is only applicable to relative paths.
@@ -15,7 +17,7 @@
       ['extra leading slash in file', '//foo/bar.rb', '/foo/bar.rb', false],
       ['extra slash in the middle of file', 'foo//bar.rb', '/foo/bar.rb', false],
       ['nothing in common', 'blah.rb', '/foo/bar.rb', false],
-      ['path is a suffix of file', '/a/foo/bar.rbr', '/foo/bar.rb', false],
+      ['path is a suffix of file', '/a/foo/bar.rb', '/foo/bar.rb', false],
 
       # We expect path to always be an absolute path.
       ['path is relative', 'bar.rb', 'bar.rb', false],
@@ -29,4 +31,36 @@
       end
     end
   end
+
+  describe '.path_can_match_spec?' do
+    # NB; when updating this list also add to the list in
+    # path_matches_suffix? test above.
+    [
+      ['exact match - absolute path', '/foo/bar.rb', '/foo/bar.rb', true],
+      # Prefixes of suffix are removed until there is a match
+      ['absolute path is a suffix', '/bar.rb', '/foo/bar.rb', true],
+      # ... but not if basename does not match
+      ['absolute path is a suffix', '/bar.rb', '/foo/bar1.rb', false],
+      ['suffix - multiple path components', 'foo/bar.rb', '/foo/bar.rb', true],
+      ['suffix - at basename', 'bar.rb', '/foo/bar.rb', true],
+      ['suffix - not at path component boundary', 'ar.rb', '/foo/bar.rb', false],
+      # Extra leading slashes are removed
+      ['extra leading slash in file', '//foo/bar.rb', '/foo/bar.rb', true],
+      # Extra slashes in the middle are also removed
+      ['extra slash in the middle of file', 'foo//bar.rb', '/foo/bar.rb', true],
+      ['nothing in common', 'blah.rb', '/foo/bar.rb', false],
+      ['path is a suffix of file', '/a/foo/bar.rb', '/foo/bar.rb', true],
+
+      # We expect path to always be an absolute path.
+      ['path is relative', 'bar.rb', 'bar.rb', false],
+    ].each do |name, suffix_, path_, result_|
+      suffix, path, result = suffix_, path_, result_
+
+      context name do
+        it "is #{result}" do
+          expect(described_class.path_can_match_spec?(path, suffix)).to be result
+        end
+      end
+    end
+  end
 end