Document _copier_conf.operation

Author: lkubb

docs/configuring.md

@@ -858,6 +858,18 @@ to know available options.
 
 The CLI option can be passed several times to add several patterns.
 
+Each pattern can be templated using Jinja.
+
+!!! example
+
+    Templating `exclude` patterns using `_copier_conf.operation` allows to have files
+    that are rendered once during `copy`, but are never updated:
+
+    ```yaml
+    _exclude:
+        - '{%- if _copier_conf.operation == "update" -%}src/*_example.py{%- endif %}'
+    ```
+
 !!! info
 
     When you define this parameter in `copier.yml`, it will **replace** the default
@@ -1316,6 +1328,8 @@ configuring `secret: true` in the [advanced prompt format][advanced-prompt-forma
 exist, but always be present. If they do not exist in a project during an `update`
 operation, they will be recreated.
 
+Each pattern can be templated using Jinja.
+
 !!! example
 
     For example, it can be used if your project generates a password the 1st time and

docs/creating.md

@@ -99,3 +99,4 @@ Copier includes:
     -   It contains the current commit hash from the template in
         `{{ _copier_conf.vcs_ref_hash }}`.
     -   Contains Operating System-specific directory separator under `sep` key.
+    -   It also contains the current `operation` (`copy` | `recopy` | `update`).