Params: remove stage deps and --all option

content/docs/command-reference/params/diff.md

@@ -7,7 +7,8 @@ commits in the <abbr>DVC repository</abbr>, or between a commit and the
 ## Synopsis
 
 ```usage
-usage: dvc params diff [-h] [-q | -v] [--show-json] [a_rev] [b_rev]
+usage: dvc params diff [-h] [-q | -v] [--all] [--show-json]
+                       [a_rev] [b_rev]
 
 positional arguments:
   a_rev          Old Git commit to compare (defaults to HEAD)
@@ -17,24 +18,25 @@ positional arguments:
 
 ## Description
 
-This command provides a quick way to compare parameter values from your previous
-experiments with the current one(s) in your <abbr>workspace</abbr>.
+This command provides a quick way to compare parameter values among experiments
+in the repository history. Requires that Git is being used to version the
+project params.
 
 > Parameter dependencies are defined with the `-p` option in `dvc run`. See also
 > `dvc params`.
 
 Run without arguments, this command compares parameters currently present in the
-<abbr>workspace</abbr> (including uncommitted changes) with the latest committed
-version.
-
-❗ It only shows parameters used in any of the currently present
-[stage files](/doc/command-reference/run) (DVC-files).
+<abbr>workspace</abbr> (uncommitted changes) with the latest committed version.
 
 Supported parameter _value_ types are: string, integer, float, and arrays. DVC
 itself does not ascribe any specific meaning for these values.
 
+❗ By default it only shows parameters that were changed.
+
 ## Options
 
+- `--all` - prints all parameters including not changed.
+
 - `--show-json` - prints the command's output in easily parsable JSON format,
   instead of a human-readable table.
 
@@ -57,9 +59,9 @@ train:
   epochs: 70
   layers: 9
 
-processing:
-  threshold: 0.98
-  bow_size: 15000
+process:
+  thresh: 0.98
+  bow: 15000
 ```
 
 Define a pipeline [stage](/doc/command-reference/run) with parameter
@@ -78,20 +80,19 @@ Let's now print parameter values that we are tracking in this
 $ dvc params diff
    Path          Param       Old     New
 params.yaml   lr             None   0.0041
-params.yaml   train.layers   None   9
+params.yaml   process.bow    None   15000
+params.yaml   process.thresh None   0.98
 params.yaml   train.epochs   None   70
+params.yaml   train.layers   None   9
 ```
 
 The command above shows the difference in parameters between the workspace and
 the last committed version of the params file `params.yaml`. Since it did not
 exist before, all `Old` values are `None`.
 
-❗ Note that not all the parameter were printed. `dvc params diff` prints only
-changed parameters that were used in one of the stages and ignores parameters
-from the group `processing` that were not used.
-
 In a project with parameters file history (params present in various Git
-commits), you will see both `Old` and `New` values:
+commits), you will see both `Old` and `New` values. However, the parameters
+won't be shown if there are no changes:
 
 ```dvc
 $ dvc params diff
@@ -101,6 +102,18 @@ params.yaml   train.layers   9      7
 params.yaml   train.epochs   70     110
 ```
 
+Specify `--all` option to see all the parameters including not changed ones:
+
+```dvc
+$ dvc params diff --all
+   Path          Param       Old     New
+params.yaml   lr             0.0041 0.0043
+params.yaml   process.bow    15000   15000
+params.yaml   process.thresh 0.98    0.98
+params.yaml   train.layers   9      7
+params.yaml   train.epochs   70     110
+```
+
 To compare parameters with a specific commit, a tag or any
 [revision](https://git-scm.com/docs/revisions) should be specified as an
 additional command line parameter:

content/docs/command-reference/params/index.md

@@ -45,9 +45,9 @@ parameters will be required for the stage invalidation (see `dvc status` and
 stage.
 
 Using parameter dependencies prevents situations where several
-[pipeline](/doc/command-reference/pipeline) stages depend on the same file, and
-any change in the file invalidates causes the reproduction all those stages
-unnecessarily.
+[pipeline](/doc/command-reference/pipeline) stages share a (configuration) file
+as a common dependency, and any change in this dependency invalidates all the
+stages and causes the reproduction those stages unnecessarily.
 
 You should manually write or generate the YAML or JSON parameters files needed
 for the project, which can be versioned directly with Git. You can then use
@@ -81,9 +81,9 @@ train:
   epochs: 70
   layers: 9
 
-processing:
-  threshold: 0.98
-  bow_size: 15000
+process:
+  thresh: 0.98
+  bow: 15000
 ```
 
 Define a [stage](/doc/command-reference/run) that depends on params `lr`,
@@ -138,12 +138,14 @@ $ dvc run -d logs/ -o users.csv \
 ## Examples: Print all parameter values in the workspace
 
 Following the previous example, we can use `dvc params diff` to list all of the
-available param values associated to DVC-files in the <abbr>workspace</abbr>:
+available param values:
 
 ```dvc
 $ dvc params diff
    Path          Param       Old     New
 params.yaml   lr             None   0.0041
+params.yaml   process.bow    None   15000
+params.yaml   process.thresh None   0.98
 params.yaml   train.layers   None   9
 params.yaml   train.epochs   None   70
 ```