模式规则依赖其他模式规则时执行顺序不符合预期

问题背景 #

我遇到了Make目标执行顺序不符合预期的问题，以下是我的Makefile：

.PHONY: deploy.%
deploy.%: DEPLOY_ENV=$*
deploy.%: fetch.% publish
    @echo "[deploy] $(DEPLOY_ENV)"

.PHONY: publish
publish:
    @echo "[publish]"

.PHONY: fetch.%
fetch.%: DEPLOY_ENV=$*
fetch.%:
    @echo "[fetch] $(DEPLOY_ENV)"

执行命令：

make deploy.dev

期望输出 #

[fetch] dev
[publish]
[deploy] dev

实际输出 #

[publish]
[fetch] dev
[deploy] dev

调试输出（关键片段） #

$ make --debug=i deploy.dev
...
Found an implicit rule for `deploy.dev'.
   File `publish' does not exist.
  Must remake target `publish'.
[publish]
  Successfully remade target file `publish'.
  File `fetch.dev' does not exist.
 Must remake target `fetch.dev'.
[fetch] dev
...

原因分析 #

GNU Make处理同一目标的多个依赖时，会优先处理非模式匹配的明确目标，再处理需要通过模式规则生成的目标。在原Makefile中，publish是明确的.PHONY目标，而fetch.%是模式目标，因此Make会先执行publish，再生成并执行fetch.dev。即使依赖列表中fetch.%写在publish前面，由于publish无需模式匹配，Make仍会优先处理它。

解决方案 #

通过目标特定依赖，让publish仅在作为deploy.%的依赖时，依赖对应的fetch.%目标，从而强制fetch.%在publish之前执行。修改后的Makefile如下：

.PHONY: deploy.%
deploy.%: DEPLOY_ENV=$*
# 为deploy.%上下文下的publish添加特定依赖
deploy.%: publish: fetch.$(DEPLOY_ENV)
deploy.%: publish
    @echo "[deploy] $(DEPLOY_ENV)"

.PHONY: publish
publish:
    @echo "[publish]"

.PHONY: fetch.%
fetch.%: DEPLOY_ENV=$*
fetch.%:
    @echo "[fetch] $(DEPLOY_ENV)"

执行make deploy.dev后，输出将符合预期：

[fetch] dev
[publish]
[deploy] dev

更简洁的写法 #

可以合并依赖定义，让代码更紧凑：

.PHONY: deploy.%
deploy.%: DEPLOY_ENV=$*
deploy.%: publish
    @echo "[deploy] $(DEPLOY_ENV)"

# 仅当publish作为deploy.%的依赖时，依赖fetch.$*
deploy.%: publish: fetch.$*

.PHONY: publish
publish:
    @echo "[publish]"

.PHONY: fetch.%
fetch.%: DEPLOY_ENV=$*
fetch.%:
    @echo "[fetch] $(DEPLOY_ENV)"

内容的提问来源于stack exchange，提问作者mamacdon