[RFC v2] coccinelle: add style check for assignment in if

From: Kris Borer
Date: Fri Aug 14 2015 - 09:41:23 EST


Add a semantic patch for fixing some cases of checkpatch.pl error:

ERROR: do not use assignment in if condition

Signed-off-by: Kris Borer <kborer@xxxxxxxxx>
---
scripts/coccinelle/style/assignment_in_if.cocci | 92 +++++++++++++++++++++++++
1 file changed, 92 insertions(+)
create mode 100644 scripts/coccinelle/style/assignment_in_if.cocci

diff --git a/scripts/coccinelle/style/assignment_in_if.cocci b/scripts/coccinelle/style/assignment_in_if.cocci
new file mode 100644
index 0000000..22ab161
--- /dev/null
+++ b/scripts/coccinelle/style/assignment_in_if.cocci
@@ -0,0 +1,92 @@
+// find checkpatch.pl errors of the type:
+// ERROR: do not use assignment in if condition
+//
+// This script is designed to correct code where assignments exist in if
+// conditions. It is only capable of handling a subset of such problems.
+//
+// For example:
+//
+// if(result = myfun())
+//
+// would become:
+//
+// result = myfun();
+// if(result)
+//
+// Confidence: Moderate
+
+
+// if ( ret = call() )
+@if1@
+identifier i;
+expression E;
+statement S1, S2;
+@@
+
++ i = E;
+ if (
+- (i = E)
++ i
+ ) S1 else S2
+
+
+// if ( (ret = call()) < 0 )
+@if2@
+identifier i;
+expression E;
+statement S1, S2;
+binary operator b;
+@@
+
++ i = E;
+ if (
+- (i = E)
++ i
+ b ... ) S1 else S2
+
+// if ( ptr->fun && (ret = ptr->fun()) < 0 )
+@if3@
+identifier i, i2;
+expression E1, E2;
+constant c;
+binary operator b;
+@@
+
++ if( E1->i ) {
++ i2 = E2;
++ if (i2 b c) {
+- if( E1->i && ((i2 = E2) b c) ) {
+ ...
+- }
++ }
++ }
+
+// if ( (ret = call()) < 0 && ret != -1 )
+@if4@
+identifier i;
+expression E, E2;
+statement S1, S2;
+binary operator b;
+@@
+
++ i = E;
+ if (
+- (i = E)
++ i
+ b
+ ... && E2 ) S1 else S2
+
+// if ( (ret = call()) < 0 && ret != -1 && ret != -2 )
+@if5@
+identifier i;
+expression E, E2, E3;
+statement S1, S2;
+binary operator b;
+@@
+
++ i = E;
+ if (
+- (i = E)
++ i
+ b
+ ... && E2 && E3 ) S1 else S2
--
1.9.1

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