Add capability to override default tags on a per-issue basis (#24)

* add: tag removal functionality with - prefix at issue level

- Enable removal of default/appended tags using - prefix in issue tags
- Process removal tags only at issue level, not in defaults
- Remove tags from final tag list after applying default logic
- Add comprehensive example file demonstrating removal functionality

Fixes #4

* test: add comprehensive tests for tag removal functionality

- Test removal of single and multiple tags from defaults
- Test removal of tags from appended (+) tags
- Test removal of non-existing tags (no-op behavior)
- Test combined removal with regular and appended tags
- Verify removal only works at issue level, not in defaults

All tests pass and cover edge cases for - prefix tag removal feature.

* doc: add tag removal example to README

- Add example showing - prefix for removing default/appended tags
- Demonstrate removal functionality in main IMYML format example
- Show how to remove tags like -bug and -enhancement at issue level

Completes documentation for tag removal feature from issue #4

Resolves issue #4

Author: briandominick

README.adoc

@@ -144,7 +144,7 @@ $meta: # optional block for establishing general modes/settings
     vrsn: 0.1.0 # milestone/version
     user: alice # assigned user
     type: Bug # type of issue (must already be registered)
-    tags: [needs_labels,+posted_by_issuer] # labels
+    tags: [needs:labels, +posted_by_issuer, +needs:docs] # labels
     stub: true # whether to auto-insert stub texts
     head: | # header stub text to prepend when indicated
       Below the next line is the body...
@@ -169,7 +169,9 @@ issues: # block for listing issues to post to cloud
     # ---
     # This is the default text that will appear if an issue record is a _stub_ and no `body` field is designated.
     # ---
-    # This issue was automatically generated by issuer. 
+    # This issue was automatically generated by issuer.
+  - summ: Documentaton issue
+    tags: [-needs:docs] # skip the default needs:docs label
 ----
 
 The `$meta` block is entirely optional, but if it is absent, your `issuer` command will need a `--proj` flag to designate the GitHub repo to which your issues should post.
@@ -277,6 +279,14 @@ Defaults to `$meta.defaults.type` or else `null`.
 `tags`:::
 (Array of Strings)
 A listing of specific labels to assign to the issue.
++
+Supports special prefix notation for label management:
++
+* Regular labels (e.g., `bug`, `priority:high`) are applied based on default tag logic
+* Append labels (e.g., `+urgent`) are always applied to all issues
+* Removal labels (e.g., `-needs:docs`) remove the specified label from the default/appended labels list
++
+Example: `tags: [documentation, +critical, -needs:review]` would add `documentation` and `critical` labels while removing any `needs:review` label from defaults.
 
 `user`:::
 (String)

examples/tag-removal-example.yml

@@ -0,0 +1,41 @@
+# Tag Removal Example - Issue #4 Implementation
+# 
+# This example demonstrates the new tag removal functionality where
+# tags prefixed with '-' are removed from the default/appended tags list.
+
+$meta:
+  proj: myorg/myrepo
+  defaults:
+    tags: [+posted-by-issuer, needs:label, +needs:docs]
+
+issues:
+  - summ: Fix misstatement in the README
+    body: |
+      Correct that really bad typo on the first paragraph.
+      No docs needed for this change since it's a docs change.
+    tags: [documentation, -needs:docs]
+  
+  - summ: Issue that will be fixed immediately
+    tags: 
+      - '-needs:label'
+
+  - summ: Complex issue with multiple tag operations
+    body: |
+      This issue demonstrates multiple tag operations:
+      - Adds bug and enhancement tags
+      - Removes the default needs:label tag
+      - Removes the appended needs:docs tag
+      - Keeps the posted-by-issuer tag (append)
+    tags: [bug, enhancement, -needs:label, -needs:docs]
+    
+  - summ: Issue with no custom tags
+    body: |
+      This issue has no custom tags, so it gets all default tags
+      including both regular defaults and append tags.
+    # No tags specified - gets all defaults
+    
+  - summ: Issue that only removes tags
+    body: |
+      This issue only removes tags, so it gets default tags
+      minus the removed ones.
+    tags: [-needs:docs]

lib/issuer/issue.rb

@@ -23,6 +23,7 @@ module Issuer
   # Tags support special prefix notation:
   # * Regular tags (e.g., +"bug"+) are only applied if the issue has no existing tags
   # * Append tags (e.g., +"+urgent"+) are always applied to all issues
+  # * Removal tags (e.g., +"-needs:docs"+) are removed from the default/appended tags list
   #
   # == Stub Composition
   #
@@ -169,28 +170,32 @@ def self.apply_stub_logic issues, defaults
 
     # Apply tag logic for this issue
     # 
-    # Processes existing tags with + prefix as append tags, combines them with
-    # CLI-provided tags, and determines final tag set based on precedence rules.
+    # Processes existing tags with + prefix as append tags, - prefix as removal tags,
+    # combines them with CLI-provided tags, and determines final tag set based on precedence rules.
     # 
     # @param cli_append_tags [Array<String>] Tags to always append from CLI
     # @param cli_default_tags [Array<String>] Default tags from CLI (used when no regular tags exist)
     # @return [void] Sets @tags instance variable
     # 
     # @example
-    #   # Issue has tags: ['+urgent', 'bug']
-    #   issue.apply_tag_logic(['cli-tag'], ['default-tag'])
-    #   # Result: ['urgent', 'cli-tag', 'bug']
+    #   # Issue has tags: ['+urgent', 'bug', '-needs:docs']
+    #   issue.apply_tag_logic(['cli-tag'], ['default-tag', 'needs:docs'])
+    #   # Result: ['urgent', 'cli-tag', 'bug', 'default-tag'] (needs:docs removed)
     def apply_tag_logic cli_append_tags, cli_default_tags
-      # Parse existing tags for + prefix
+      # Parse existing tags for + and - prefixes
       existing_tags = tags || []
       append_tags = []
       regular_tags = []
+      remove_tags = []
 
       existing_tags.each do |tag|
-        if tag.to_s.start_with?('+')
-          append_tags << tag.to_s[1..] # Remove + prefix
+        tag_str = tag.to_s
+        if tag_str.start_with?('+')
+          append_tags << tag_str[1..] # Remove + prefix
+        elsif tag_str.start_with?('-')
+          remove_tags << tag_str[1..] # Remove - prefix
         else
-          regular_tags << tag.to_s
+          regular_tags << tag_str
         end
       end
 
@@ -199,21 +204,27 @@ def apply_tag_logic cli_append_tags, cli_default_tags
       final_tags = append_tags + defaults_append_tags + cli_append_tags
 
       # For regular tags, add issue's own tags, otherwise use default tags
-      issue_regular_tags = Array(@raw_data['tags']).reject { |tag| tag.to_s.start_with?('+') }
+      issue_regular_tags = Array(@raw_data['tags']).reject { |tag| tag.to_s.start_with?('+') || tag.to_s.start_with?('-') }
 
       if !issue_regular_tags.empty?
         # Issue has its own regular tags, use them
         final_tags.concat(issue_regular_tags)
       else
         # Issue has no regular tags, use defaults from CLI
         final_tags.concat(cli_default_tags)
-        # Also add non-append defaults tags
+        # Also add non-append defaults tags (- prefix ignored in defaults)
         defaults_regular_tags = Array(@defaults['tags']).reject { |tag| tag.to_s.start_with?('+') }
         final_tags.concat(defaults_regular_tags)
       end
 
-      # Set the final tags (removing duplicates)
-      @tags = final_tags.uniq
+      # Collect removal tags from issue only (not defaults)
+      all_remove_tags = remove_tags
+      
+      # Remove duplicates first, then remove tags specified for removal
+      final_tags = final_tags.uniq - all_remove_tags
+      
+      # Set the final tags
+      @tags = final_tags
     end
 
     # Apply stub logic for this issue
@@ -259,7 +270,8 @@ def apply_stub_logic defaults
     # 
     # Separates tags with + prefix (append tags) from regular tags (default tags).
     # Tags with + prefix are always applied, while regular tags are only used
-    # when the issue has no existing regular tags.
+    # when the issue has no existing regular tags. Tags with - prefix are handled
+    # in the apply_tag_logic method for removal.
     # 
     # @param tags_string [String] Comma-separated tag string
     # @return [Array<Array<String>>] Two-element array: [append_tags, default_tags]

specs/tests/rspec/issue_spec.rb

@@ -349,6 +349,78 @@
           expect(issue.tags).to contain_exactly('posted-by-issuer', 'cli-default', 'needs-label')
         end
       end
+      
+      context 'with removal tags (-prefix)' do
+        it 'removes tags specified with - prefix from issue tags' do
+          issue_data = { 'summ' => 'Test', 'tags' => ['bug', '-needs-label'] }
+          issue = described_class.new(issue_data, defaults)
+          
+          issue.apply_tag_logic([], [])
+          
+          expect(issue.tags).to contain_exactly('posted-by-issuer', 'bug')
+          expect(issue.tags).not_to include('needs-label')
+        end
+        
+        it 'removes append tags specified with - prefix' do
+          issue_data = { 'summ' => 'Test', 'tags' => ['bug', '-posted-by-issuer'] }
+          issue = described_class.new(issue_data, defaults)
+          
+          issue.apply_tag_logic([], [])
+          
+          expect(issue.tags).to contain_exactly('bug')
+          expect(issue.tags).not_to include('posted-by-issuer')
+        end
+        
+        it 'handles multiple removal tags' do
+          issue_data = { 'summ' => 'Test', 'tags' => ['bug', 'enhancement', '-needs-label', '-posted-by-issuer'] }
+          issue = described_class.new(issue_data, defaults)
+          
+          issue.apply_tag_logic([], [])
+          
+          expect(issue.tags).to contain_exactly('bug', 'enhancement')
+          expect(issue.tags).not_to include('needs-label', 'posted-by-issuer')
+        end
+        
+        it 'handles removal tags when no matching tags exist' do
+          issue_data = { 'summ' => 'Test', 'tags' => ['bug', '-nonexistent-tag'] }
+          issue = described_class.new(issue_data, defaults)
+          
+          issue.apply_tag_logic([], [])
+          
+          expect(issue.tags).to contain_exactly('posted-by-issuer', 'bug')
+        end
+        
+        it 'processes removal tags with CLI tags' do
+          issue_data = { 'summ' => 'Test', 'tags' => ['bug', '-needs-label'] }
+          issue = described_class.new(issue_data, defaults)
+          
+          issue.apply_tag_logic(['cli-urgent'], ['cli-default'])
+          
+          expect(issue.tags).to contain_exactly('posted-by-issuer', 'cli-urgent', 'bug')
+          expect(issue.tags).not_to include('needs-label')
+        end
+        
+        it 'handles colon-separated tags in removal (needs:docs example)' do
+          defaults_with_colon = { 'tags' => ['+posted-by-issuer', 'needs:docs', 'needs:label'] }
+          issue_data = { 'summ' => 'Test', 'tags' => ['documentation', '-needs:docs'] }
+          issue = described_class.new(issue_data, defaults_with_colon)
+          
+          issue.apply_tag_logic([], [])
+          
+          expect(issue.tags).to contain_exactly('posted-by-issuer', 'documentation')
+          expect(issue.tags).not_to include('needs:docs')
+        end
+        
+        it 'handles string format removal tags' do
+          issue_data = { 'summ' => 'Test', 'tags' => ['-needs-label'] }
+          issue = described_class.new(issue_data, defaults)
+          
+          issue.apply_tag_logic([], [])
+          
+          expect(issue.tags).to contain_exactly('posted-by-issuer')
+          expect(issue.tags).not_to include('needs-label')
+        end
+      end
     end
 
     describe '.parse_tag_logic' do