Stop maintaining a list of lint targets

instead, configure the tools to find sensible targets.

Pulled out from #12337; part (but not all) of
e53e99e. Related: #12107.

Author: David Robertson

docs/code_style.md

@@ -24,7 +24,7 @@ pip install -e ".[lint,mypy]"
     functionality) with:
 
     ```sh
-    black . --exclude="\.tox|build|env"
+    black .
     ```
 
 -   **flake8**
@@ -35,7 +35,7 @@ pip install -e ".[lint,mypy]"
     Check all application and test code with:
 
     ```sh
-    flake8 synapse tests
+    flake8 .
     ```
 
 -   **isort**
@@ -46,11 +46,9 @@ pip install -e ".[lint,mypy]"
     Auto-fix imports with:
 
     ```sh
-    isort -rc synapse tests
+    isort .
     ```
 
-    `-rc` means to recursively search the given directories.
-
 It's worth noting that modern IDEs and text editors can run these tools
 automatically on save. It may be worth looking into whether this
 functionality is supported in your editor for a more convenient

pyproject.toml

@@ -36,24 +36,9 @@
 
 [tool.black]
 target-version = ['py37', 'py38', 'py39', 'py310']
-exclude = '''
-
-(
-  /(
-      \.eggs         # exclude a few common directories in the
-    | \.git          # root of the project
-    | \.tox
-    | \.venv
-    | \.env
-    | env
-    | _build
-    | _trial_temp.*
-    | build
-    | dist
-    | debian
-  )/
-)
-'''
+# black ignores everything in .gitignore by default, see
+# https://black.readthedocs.io/en/stable/usage_and_configuration/file_collection_and_discovery.html#gitignore
+# Use `extend-exclude` if you want to exclude something in addition to this.
 
 [tool.isort]
 line_length = 88
@@ -65,6 +50,7 @@ known_twisted = ["twisted", "OpenSSL"]
 multi_line_output = 3
 include_trailing_comma = true
 combine_as_imports = true
+skip_gitignore = true
 
 [tool.poetry]
 name = "matrix-synapse"

scripts-dev/lint.sh

@@ -80,13 +80,7 @@ else
   # then lint everything!
   if [[ -z ${files+x} ]]; then
     # Lint all source code files and directories
-    # Note: this list aims to mirror the one in tox.ini
-      files=(
-          "synapse" "docker" "tests"
-          # annoyingly, black doesn't find these so we have to list them
-          "scripts-dev"
-          "contrib" "setup.py" "synmark" "stubs" ".ci"
-      )
+      files=( "." )
   fi
 fi
 

tox.ini

@@ -33,7 +33,7 @@ deps =
     pip>=10
 
 # directories/files we run the linters on.
-# if you update this list, make sure to do the same in scripts-dev/lint.sh
+# TODO: this is now out of date; we will remove as part of poetry migration.
 lint_targets =
     setup.py
     synapse