lib/common.mk: avoid using uninitialized variables

It somehow managed to evade me that $(TMP) might be uninitialized; definitely should be checked before stuffing into sed substitution command. NB: this could be done in pure make but my take was less readable. Thanks shadowsbrother/gmail for hitting and reporting this.

lib/common.mk: avoid using uninitialized variables
860e20c6 · Michael Shigorin · 74e5734e · 860e20c6
Commit 860e20c6 authored May 26, 2012 by Michael Shigorin
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Showing with 11 additions and 4 deletions

common.mk lib/common.mk +11 -4

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--- a/lib/common.mk
+++ b/lib/common.mk
@@ -7,10 +7,17 @@ BUILD_LOG = build.log
 SYMLINK = build

 # brevity postprocessor; not exported, for toplevel use only
-SHORTEN = $(shell \
-	echo -n "| sed"; \
+SHORTEN = $(shell FILTER=; \
 	if [ -s "$(SYMLINK)" ]; then \
-		echo -n " -e 's,$(BUILDDIR),$(SYMLINK),'"; \
+		FILTER=" -e 's,$(BUILDDIR),$(SYMLINK),'"; \
+	fi; \
+	if [ -n "$$TMP" ]; then \
+		FILTER="$$FILTER -e 's,$$TMP,\$$TMP,'"; \
+	fi; \
+	if [ -n "$$HOME" ]; then \
+		FILTER="$$FILTER -e 's,$$HOME,~,'"; \
+	fi; \
+	if [ -n "$$FILTER" ]; then \
+		echo -n "| sed $$FILTER"; \
 	fi; \
-	echo -n " -e 's,$(TMP),\$$TMP,' -e 's,$(HOME),~,'"; \
 )