Nix Cookbook: Difference between revisions

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== Deprecating input ~~parameters~~ in mkDerivation-style packages ==

== Deprecating a specific input parameter in mkDerivation-style packages ==

Sometimes we want to rename an input parameter.

Sometimes we want to rename some input parameter in .

E.G. an option `withX` that enables the X11 GUI for a certain app:

Line 137:

withX ? true,

/*. . .*/

}

}:

stdenv.mkDerivation { /* . . . */}

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Suppose that a new version of this package features a more agnostic GUI that can be linked to X11, GTK, Qt etc.

Because of it, `withX` is no longer a ~~well~~ descriptive name for this functionality.

Because of it, `withX` is no longer a descriptive name for this functionality.

~~Renaming~~ the parameter is dangerous, because other functions that call this function expect this parameter.

However, renaming the parameter is dangerous, because other functions that call this function expect this parameter.

~~This~~ problem becomes more pronounced when in conjunction with custom, third-party overlays.

The problem becomes more pronounced when in conjunction with custom, third-party overlays.

The solution is, roughly, emit a warning about the old parameter being used, reporting the user to the new parameter:

The solution is, roughly, to emit a warning about the old parameter being used, reporting the user to the new parameter:

@@ Line 126: / Line 126: @@
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-== Deprecating input parameters in mkDerivation-style packages ==
+== Deprecating a specific input parameter in mkDerivation-style packages ==
-Sometimes we want to rename an input parameter.
+Sometimes we want to rename some input parameter in .
 E.G. an option `withX` that enables the X11 GUI for a certain app:
@@ Line 137: / Line 137: @@
    withX ? true,
    /*. . .*/
-}
+}:
+stdenv.mkDerivation { /* . . . */}
 </syntaxHighlight>
 Suppose that a new version of this package features a more agnostic GUI that can be linked to X11, GTK, Qt etc.
-Because of it, `withX` is no longer a well descriptive name for this functionality.
+Because of it, `withX` is no longer a descriptive name for this functionality.
-Renaming the parameter is dangerous, because other functions that call this function expect this parameter.
+However, renaming the parameter is dangerous, because other functions that call this function expect this parameter.
-This problem becomes more pronounced when in conjunction with custom, third-party overlays.
+The problem becomes more pronounced when in conjunction with custom, third-party overlays.
-The solution is, roughly, emit a warning about the old parameter being used, reporting the user to the new parameter:
+The solution is, roughly, to emit a warning about the old parameter being used, reporting the user to the new parameter:
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